From f8d5d0cc145cc21bfc56ef807dc28102aebbf228 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 7 Nov 2017 16:30:10 -0500 Subject: xarray: Add definition of struct xarray This is a direct replacement for struct radix_tree_root. Some of the struct members have changed name; convert those, and use a #define so that radix_tree users continue to work without change. Signed-off-by: Matthew Wilcox Reviewed-by: Josef Bacik --- lib/xarray.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 lib/xarray.c (limited to 'lib/xarray.c') diff --git a/lib/xarray.c b/lib/xarray.c new file mode 100644 index 000000000000..862f4c64c754 --- /dev/null +++ b/lib/xarray.c @@ -0,0 +1,44 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * XArray implementation + * Copyright (c) 2017 Microsoft Corporation + * Author: Matthew Wilcox + */ + +#include +#include + +/* + * Coding conventions in this file: + * + * @xa is used to refer to the entire xarray. + * @xas is the 'xarray operation state'. It may be either a pointer to + * an xa_state, or an xa_state stored on the stack. This is an unfortunate + * ambiguity. + * @index is the index of the entry being operated on + * @mark is an xa_mark_t; a small number indicating one of the mark bits. + * @node refers to an xa_node; usually the primary one being operated on by + * this function. + * @offset is the index into the slots array inside an xa_node. + * @parent refers to the @xa_node closer to the head than @node. + * @entry refers to something stored in a slot in the xarray + */ + +/** + * xa_init_flags() - Initialise an empty XArray with flags. + * @xa: XArray. + * @flags: XA_FLAG values. + * + * If you need to initialise an XArray with special flags (eg you need + * to take the lock from interrupt context), use this function instead + * of xa_init(). + * + * Context: Any context. + */ +void xa_init_flags(struct xarray *xa, gfp_t flags) +{ + spin_lock_init(&xa->xa_lock); + xa->xa_flags = flags; + xa->xa_head = NULL; +} +EXPORT_SYMBOL(xa_init_flags); -- cgit v1.2.3 From ad3d6c7263e368abdc151e1cc13dc78aa39cc7a7 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 7 Nov 2017 14:57:46 -0500 Subject: xarray: Add XArray load operation The xa_load function brings with it a lot of infrastructure; xa_empty(), xa_is_err(), and large chunks of the XArray advanced API that are used to implement xa_load. As the test-suite demonstrates, it is possible to use the XArray functions on a radix tree. The radix tree functions depend on the GFP flags being stored in the root of the tree, so it's not possible to use the radix tree functions on an XArray. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 336 ++++++++++++++++++++++++++++++ lib/Kconfig.debug | 3 + lib/Makefile | 1 + lib/radix-tree.c | 43 ---- lib/test_xarray.c | 87 ++++++++ lib/xarray.c | 195 +++++++++++++++++ tools/include/linux/kernel.h | 1 + tools/testing/radix-tree/.gitignore | 1 + tools/testing/radix-tree/Makefile | 6 +- tools/testing/radix-tree/linux/kernel.h | 1 + tools/testing/radix-tree/linux/rcupdate.h | 2 + tools/testing/radix-tree/main.c | 1 + tools/testing/radix-tree/test.h | 1 + tools/testing/radix-tree/xarray.c | 28 +++ 14 files changed, 661 insertions(+), 45 deletions(-) create mode 100644 lib/test_xarray.c (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 52141dfc5a90..a0df8217068c 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include #include @@ -30,6 +32,10 @@ * * 0-62: Sibling entries * 256: Retry entry + * + * Errors are also represented as internal entries, but use the negative + * space (-4094 to -2). They're never stored in the slots array; only + * returned by the normal API. */ #define BITS_PER_XA_VALUE (BITS_PER_LONG - 1) @@ -155,6 +161,42 @@ static inline bool xa_is_internal(const void *entry) return ((unsigned long)entry & 3) == 2; } +/** + * xa_is_err() - Report whether an XArray operation returned an error + * @entry: Result from calling an XArray function + * + * If an XArray operation cannot complete an operation, it will return + * a special value indicating an error. This function tells you + * whether an error occurred; xa_err() tells you which error occurred. + * + * Context: Any context. + * Return: %true if the entry indicates an error. + */ +static inline bool xa_is_err(const void *entry) +{ + return unlikely(xa_is_internal(entry)); +} + +/** + * xa_err() - Turn an XArray result into an errno. + * @entry: Result from calling an XArray function. + * + * If an XArray operation cannot complete an operation, it will return + * a special pointer value which encodes an errno. This function extracts + * the errno from the pointer value, or returns 0 if the pointer does not + * represent an errno. + * + * Context: Any context. + * Return: A negative errno or 0. + */ +static inline int xa_err(void *entry) +{ + /* xa_to_internal() would not do sign extension. */ + if (xa_is_err(entry)) + return (long)entry >> 2; + return 0; +} + /** * struct xarray - The anchor of the XArray. * @xa_lock: Lock that protects the contents of the XArray. @@ -209,6 +251,7 @@ struct xarray { #define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0) void xa_init_flags(struct xarray *, gfp_t flags); +void *xa_load(struct xarray *, unsigned long index); /** * xa_init() - Initialise an empty XArray. @@ -223,6 +266,18 @@ static inline void xa_init(struct xarray *xa) xa_init_flags(xa, 0); } +/** + * xa_empty() - Determine if an array has any present entries. + * @xa: XArray. + * + * Context: Any context. + * Return: %true if the array contains only NULL pointers. + */ +static inline bool xa_empty(const struct xarray *xa) +{ + return xa->xa_head == NULL; +} + #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) #define xa_lock(xa) spin_lock(&(xa)->xa_lock) #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) @@ -280,6 +335,65 @@ struct xa_node { }; }; +void xa_dump(const struct xarray *); +void xa_dump_node(const struct xa_node *); + +#ifdef XA_DEBUG +#define XA_BUG_ON(xa, x) do { \ + if (x) { \ + xa_dump(xa); \ + BUG(); \ + } \ + } while (0) +#define XA_NODE_BUG_ON(node, x) do { \ + if (x) { \ + if (node) xa_dump_node(node); \ + BUG(); \ + } \ + } while (0) +#else +#define XA_BUG_ON(xa, x) do { } while (0) +#define XA_NODE_BUG_ON(node, x) do { } while (0) +#endif + +/* Private */ +static inline void *xa_head(const struct xarray *xa) +{ + return rcu_dereference_check(xa->xa_head, + lockdep_is_held(&xa->xa_lock)); +} + +/* Private */ +static inline void *xa_head_locked(const struct xarray *xa) +{ + return rcu_dereference_protected(xa->xa_head, + lockdep_is_held(&xa->xa_lock)); +} + +/* Private */ +static inline void *xa_entry(const struct xarray *xa, + const struct xa_node *node, unsigned int offset) +{ + XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); + return rcu_dereference_check(node->slots[offset], + lockdep_is_held(&xa->xa_lock)); +} + +/* Private */ +static inline void *xa_entry_locked(const struct xarray *xa, + const struct xa_node *node, unsigned int offset) +{ + XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); + return rcu_dereference_protected(node->slots[offset], + lockdep_is_held(&xa->xa_lock)); +} + +/* Private */ +static inline struct xa_node *xa_to_node(const void *entry) +{ + return (struct xa_node *)((unsigned long)entry - 2); +} + /* Private */ static inline bool xa_is_node(const void *entry) { @@ -312,4 +426,226 @@ static inline bool xa_is_sibling(const void *entry) #define XA_RETRY_ENTRY xa_mk_internal(256) +/** + * xa_is_retry() - Is the entry a retry entry? + * @entry: Entry retrieved from the XArray + * + * Return: %true if the entry is a retry entry. + */ +static inline bool xa_is_retry(const void *entry) +{ + return unlikely(entry == XA_RETRY_ENTRY); +} + +/** + * typedef xa_update_node_t - A callback function from the XArray. + * @node: The node which is being processed + * + * This function is called every time the XArray updates the count of + * present and value entries in a node. It allows advanced users to + * maintain the private_list in the node. + * + * Context: The xa_lock is held and interrupts may be disabled. + * Implementations should not drop the xa_lock, nor re-enable + * interrupts. + */ +typedef void (*xa_update_node_t)(struct xa_node *node); + +/* + * The xa_state is opaque to its users. It contains various different pieces + * of state involved in the current operation on the XArray. It should be + * declared on the stack and passed between the various internal routines. + * The various elements in it should not be accessed directly, but only + * through the provided accessor functions. The below documentation is for + * the benefit of those working on the code, not for users of the XArray. + * + * @xa_node usually points to the xa_node containing the slot we're operating + * on (and @xa_offset is the offset in the slots array). If there is a + * single entry in the array at index 0, there are no allocated xa_nodes to + * point to, and so we store %NULL in @xa_node. @xa_node is set to + * the value %XAS_RESTART if the xa_state is not walked to the correct + * position in the tree of nodes for this operation. If an error occurs + * during an operation, it is set to an %XAS_ERROR value. If we run off the + * end of the allocated nodes, it is set to %XAS_BOUNDS. + */ +struct xa_state { + struct xarray *xa; + unsigned long xa_index; + unsigned char xa_shift; + unsigned char xa_sibs; + unsigned char xa_offset; + unsigned char xa_pad; /* Helps gcc generate better code */ + struct xa_node *xa_node; + struct xa_node *xa_alloc; + xa_update_node_t xa_update; +}; + +/* + * We encode errnos in the xas->xa_node. If an error has happened, we need to + * drop the lock to fix it, and once we've done so the xa_state is invalid. + */ +#define XA_ERROR(errno) ((struct xa_node *)(((unsigned long)errno << 2) | 2UL)) +#define XAS_BOUNDS ((struct xa_node *)1UL) +#define XAS_RESTART ((struct xa_node *)3UL) + +#define __XA_STATE(array, index, shift, sibs) { \ + .xa = array, \ + .xa_index = index, \ + .xa_shift = shift, \ + .xa_sibs = sibs, \ + .xa_offset = 0, \ + .xa_pad = 0, \ + .xa_node = XAS_RESTART, \ + .xa_alloc = NULL, \ + .xa_update = NULL \ +} + +/** + * XA_STATE() - Declare an XArray operation state. + * @name: Name of this operation state (usually xas). + * @array: Array to operate on. + * @index: Initial index of interest. + * + * Declare and initialise an xa_state on the stack. + */ +#define XA_STATE(name, array, index) \ + struct xa_state name = __XA_STATE(array, index, 0, 0) + +/** + * XA_STATE_ORDER() - Declare an XArray operation state. + * @name: Name of this operation state (usually xas). + * @array: Array to operate on. + * @index: Initial index of interest. + * @order: Order of entry. + * + * Declare and initialise an xa_state on the stack. This variant of + * XA_STATE() allows you to specify the 'order' of the element you + * want to operate on.` + */ +#define XA_STATE_ORDER(name, array, index, order) \ + struct xa_state name = __XA_STATE(array, \ + (index >> order) << order, \ + order - (order % XA_CHUNK_SHIFT), \ + (1U << (order % XA_CHUNK_SHIFT)) - 1) + +#define xas_marked(xas, mark) xa_marked((xas)->xa, (mark)) +#define xas_trylock(xas) xa_trylock((xas)->xa) +#define xas_lock(xas) xa_lock((xas)->xa) +#define xas_unlock(xas) xa_unlock((xas)->xa) +#define xas_lock_bh(xas) xa_lock_bh((xas)->xa) +#define xas_unlock_bh(xas) xa_unlock_bh((xas)->xa) +#define xas_lock_irq(xas) xa_lock_irq((xas)->xa) +#define xas_unlock_irq(xas) xa_unlock_irq((xas)->xa) +#define xas_lock_irqsave(xas, flags) \ + xa_lock_irqsave((xas)->xa, flags) +#define xas_unlock_irqrestore(xas, flags) \ + xa_unlock_irqrestore((xas)->xa, flags) + +/** + * xas_error() - Return an errno stored in the xa_state. + * @xas: XArray operation state. + * + * Return: 0 if no error has been noted. A negative errno if one has. + */ +static inline int xas_error(const struct xa_state *xas) +{ + return xa_err(xas->xa_node); +} + +/** + * xas_set_err() - Note an error in the xa_state. + * @xas: XArray operation state. + * @err: Negative error number. + * + * Only call this function with a negative @err; zero or positive errors + * will probably not behave the way you think they should. If you want + * to clear the error from an xa_state, use xas_reset(). + */ +static inline void xas_set_err(struct xa_state *xas, long err) +{ + xas->xa_node = XA_ERROR(err); +} + +/** + * xas_invalid() - Is the xas in a retry or error state? + * @xas: XArray operation state. + * + * Return: %true if the xas cannot be used for operations. + */ +static inline bool xas_invalid(const struct xa_state *xas) +{ + return (unsigned long)xas->xa_node & 3; +} + +/** + * xas_valid() - Is the xas a valid cursor into the array? + * @xas: XArray operation state. + * + * Return: %true if the xas can be used for operations. + */ +static inline bool xas_valid(const struct xa_state *xas) +{ + return !xas_invalid(xas); +} + +/** + * xas_reset() - Reset an XArray operation state. + * @xas: XArray operation state. + * + * Resets the error or walk state of the @xas so future walks of the + * array will start from the root. Use this if you have dropped the + * xarray lock and want to reuse the xa_state. + * + * Context: Any context. + */ +static inline void xas_reset(struct xa_state *xas) +{ + xas->xa_node = XAS_RESTART; +} + +/** + * xas_retry() - Retry the operation if appropriate. + * @xas: XArray operation state. + * @entry: Entry from xarray. + * + * The advanced functions may sometimes return an internal entry, such as + * a retry entry or a zero entry. This function sets up the @xas to restart + * the walk from the head of the array if needed. + * + * Context: Any context. + * Return: true if the operation needs to be retried. + */ +static inline bool xas_retry(struct xa_state *xas, const void *entry) +{ + if (!xa_is_retry(entry)) + return false; + xas_reset(xas); + return true; +} + +void *xas_load(struct xa_state *); + +/** + * xas_reload() - Refetch an entry from the xarray. + * @xas: XArray operation state. + * + * Use this function to check that a previously loaded entry still has + * the same value. This is useful for the lockless pagecache lookup where + * we walk the array with only the RCU lock to protect us, lock the page, + * then check that the page hasn't moved since we looked it up. + * + * The caller guarantees that @xas is still valid. If it may be in an + * error or restart state, call xas_load() instead. + * + * Return: The entry at this location in the xarray. + */ +static inline void *xas_reload(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (node) + return xa_entry(xas->xa, node, xas->xa_offset); + return xa_head(xas->xa); +} + #endif /* _LINUX_XARRAY_H */ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4966c4fbe7f7..091155e12422 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1813,6 +1813,9 @@ config TEST_BITFIELD config TEST_UUID tristate "Test functions located in the uuid module at runtime" +config TEST_XARRAY + tristate "Test the XArray code at runtime" + config TEST_OVERFLOW tristate "Test check_*_overflow() functions at runtime" diff --git a/lib/Makefile b/lib/Makefile index 057385f1f145..e6f809556af5 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -68,6 +68,7 @@ obj-$(CONFIG_TEST_PRINTF) += test_printf.o obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o obj-$(CONFIG_TEST_BITFIELD) += test_bitfield.o obj-$(CONFIG_TEST_UUID) += test_uuid.o +obj-$(CONFIG_TEST_XARRAY) += test_xarray.o obj-$(CONFIG_TEST_PARMAN) += test_parman.o obj-$(CONFIG_TEST_KMOD) += test_kmod.o obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 8a568cea1237..b8e961428484 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -256,49 +256,6 @@ static unsigned long next_index(unsigned long index, } #ifndef __KERNEL__ -static void dump_node(struct radix_tree_node *node, unsigned long index) -{ - unsigned long i; - - pr_debug("radix node: %p offset %d indices %lu-%lu parent %p tags %lx %lx %lx shift %d count %d nr_values %d\n", - node, node->offset, index, index | node_maxindex(node), - node->parent, - node->tags[0][0], node->tags[1][0], node->tags[2][0], - node->shift, node->count, node->nr_values); - - for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { - unsigned long first = index | (i << node->shift); - unsigned long last = first | ((1UL << node->shift) - 1); - void *entry = node->slots[i]; - if (!entry) - continue; - if (entry == RADIX_TREE_RETRY) { - pr_debug("radix retry offset %ld indices %lu-%lu parent %p\n", - i, first, last, node); - } else if (!radix_tree_is_internal_node(entry)) { - pr_debug("radix entry %p offset %ld indices %lu-%lu parent %p\n", - entry, i, first, last, node); - } else if (xa_is_sibling(entry)) { - pr_debug("radix sblng %p offset %ld indices %lu-%lu parent %p val %p\n", - entry, i, first, last, node, - node->slots[xa_to_sibling(entry)]); - } else { - dump_node(entry_to_node(entry), first); - } - } -} - -/* For debug */ -static void radix_tree_dump(struct radix_tree_root *root) -{ - pr_debug("radix root: %p xa_head %p tags %x\n", - root, root->xa_head, - root->xa_flags >> ROOT_TAG_SHIFT); - if (!radix_tree_is_internal_node(root->xa_head)) - return; - dump_node(entry_to_node(root->xa_head), 0); -} - static void dump_ida_node(void *entry, unsigned long index) { unsigned long i; diff --git a/lib/test_xarray.c b/lib/test_xarray.c new file mode 100644 index 000000000000..a7248b87617f --- /dev/null +++ b/lib/test_xarray.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * test_xarray.c: Test the XArray API + * Copyright (c) 2017-2018 Microsoft Corporation + * Author: Matthew Wilcox + */ + +#include +#include + +static unsigned int tests_run; +static unsigned int tests_passed; + +#ifndef XA_DEBUG +# ifdef __KERNEL__ +void xa_dump(const struct xarray *xa) { } +# endif +#undef XA_BUG_ON +#define XA_BUG_ON(xa, x) do { \ + tests_run++; \ + if (x) { \ + printk("BUG at %s:%d\n", __func__, __LINE__); \ + xa_dump(xa); \ + dump_stack(); \ + } else { \ + tests_passed++; \ + } \ +} while (0) +#endif + +static void *xa_store_index(struct xarray *xa, unsigned long index, gfp_t gfp) +{ + radix_tree_insert(xa, index, xa_mk_value(index)); + return NULL; +} + +static void xa_erase_index(struct xarray *xa, unsigned long index) +{ + radix_tree_delete(xa, index); +} + +static noinline void check_xa_load(struct xarray *xa) +{ + unsigned long i, j; + + for (i = 0; i < 1024; i++) { + for (j = 0; j < 1024; j++) { + void *entry = xa_load(xa, j); + if (j < i) + XA_BUG_ON(xa, xa_to_value(entry) != j); + else + XA_BUG_ON(xa, entry); + } + XA_BUG_ON(xa, xa_store_index(xa, i, GFP_KERNEL) != NULL); + } + + for (i = 0; i < 1024; i++) { + for (j = 0; j < 1024; j++) { + void *entry = xa_load(xa, j); + if (j >= i) + XA_BUG_ON(xa, xa_to_value(entry) != j); + else + XA_BUG_ON(xa, entry); + } + xa_erase_index(xa, i); + } + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static RADIX_TREE(array, GFP_KERNEL); + +static int xarray_checks(void) +{ + check_xa_load(&array); + + printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); + return (tests_run == tests_passed) ? 0 : -EINVAL; +} + +static void xarray_exit(void) +{ +} + +module_init(xarray_checks); +module_exit(xarray_exit); +MODULE_AUTHOR("Matthew Wilcox "); +MODULE_LICENSE("GPL"); diff --git a/lib/xarray.c b/lib/xarray.c index 862f4c64c754..19cfcbc69a68 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -24,6 +24,100 @@ * @entry refers to something stored in a slot in the xarray */ +/* extracts the offset within this node from the index */ +static unsigned int get_offset(unsigned long index, struct xa_node *node) +{ + return (index >> node->shift) & XA_CHUNK_MASK; +} + +/* move the index either forwards (find) or backwards (sibling slot) */ +static void xas_move_index(struct xa_state *xas, unsigned long offset) +{ + unsigned int shift = xas->xa_node->shift; + xas->xa_index &= ~XA_CHUNK_MASK << shift; + xas->xa_index += offset << shift; +} + +static void *set_bounds(struct xa_state *xas) +{ + xas->xa_node = XAS_BOUNDS; + return NULL; +} + +/* + * Starts a walk. If the @xas is already valid, we assume that it's on + * the right path and just return where we've got to. If we're in an + * error state, return NULL. If the index is outside the current scope + * of the xarray, return NULL without changing @xas->xa_node. Otherwise + * set @xas->xa_node to NULL and return the current head of the array. + */ +static void *xas_start(struct xa_state *xas) +{ + void *entry; + + if (xas_valid(xas)) + return xas_reload(xas); + if (xas_error(xas)) + return NULL; + + entry = xa_head(xas->xa); + if (!xa_is_node(entry)) { + if (xas->xa_index) + return set_bounds(xas); + } else { + if ((xas->xa_index >> xa_to_node(entry)->shift) > XA_CHUNK_MASK) + return set_bounds(xas); + } + + xas->xa_node = NULL; + return entry; +} + +static void *xas_descend(struct xa_state *xas, struct xa_node *node) +{ + unsigned int offset = get_offset(xas->xa_index, node); + void *entry = xa_entry(xas->xa, node, offset); + + xas->xa_node = node; + if (xa_is_sibling(entry)) { + offset = xa_to_sibling(entry); + entry = xa_entry(xas->xa, node, offset); + } + + xas->xa_offset = offset; + return entry; +} + +/** + * xas_load() - Load an entry from the XArray (advanced). + * @xas: XArray operation state. + * + * Usually walks the @xas to the appropriate state to load the entry + * stored at xa_index. However, it will do nothing and return %NULL if + * @xas is in an error state. xas_load() will never expand the tree. + * + * If the xa_state is set up to operate on a multi-index entry, xas_load() + * may return %NULL or an internal entry, even if there are entries + * present within the range specified by @xas. + * + * Context: Any context. The caller should hold the xa_lock or the RCU lock. + * Return: Usually an entry in the XArray, but see description for exceptions. + */ +void *xas_load(struct xa_state *xas) +{ + void *entry = xas_start(xas); + + while (xa_is_node(entry)) { + struct xa_node *node = xa_to_node(entry); + + if (xas->xa_shift > node->shift) + break; + entry = xas_descend(xas, node); + } + return entry; +} +EXPORT_SYMBOL_GPL(xas_load); + /** * xa_init_flags() - Initialise an empty XArray with flags. * @xa: XArray. @@ -42,3 +136,104 @@ void xa_init_flags(struct xarray *xa, gfp_t flags) xa->xa_head = NULL; } EXPORT_SYMBOL(xa_init_flags); + +/** + * xa_load() - Load an entry from an XArray. + * @xa: XArray. + * @index: index into array. + * + * Context: Any context. Takes and releases the RCU lock. + * Return: The entry at @index in @xa. + */ +void *xa_load(struct xarray *xa, unsigned long index) +{ + XA_STATE(xas, xa, index); + void *entry; + + rcu_read_lock(); + do { + entry = xas_load(&xas); + } while (xas_retry(&xas, entry)); + rcu_read_unlock(); + + return entry; +} +EXPORT_SYMBOL(xa_load); + +#ifdef XA_DEBUG +void xa_dump_node(const struct xa_node *node) +{ + unsigned i, j; + + if (!node) + return; + if ((unsigned long)node & 3) { + pr_cont("node %px\n", node); + return; + } + + pr_cont("node %px %s %d parent %px shift %d count %d values %d " + "array %px list %px %px marks", + node, node->parent ? "offset" : "max", node->offset, + node->parent, node->shift, node->count, node->nr_values, + node->array, node->private_list.prev, node->private_list.next); + for (i = 0; i < XA_MAX_MARKS; i++) + for (j = 0; j < XA_MARK_LONGS; j++) + pr_cont(" %lx", node->marks[i][j]); + pr_cont("\n"); +} + +void xa_dump_index(unsigned long index, unsigned int shift) +{ + if (!shift) + pr_info("%lu: ", index); + else if (shift >= BITS_PER_LONG) + pr_info("0-%lu: ", ~0UL); + else + pr_info("%lu-%lu: ", index, index | ((1UL << shift) - 1)); +} + +void xa_dump_entry(const void *entry, unsigned long index, unsigned long shift) +{ + if (!entry) + return; + + xa_dump_index(index, shift); + + if (xa_is_node(entry)) { + if (shift == 0) { + pr_cont("%px\n", entry); + } else { + unsigned long i; + struct xa_node *node = xa_to_node(entry); + xa_dump_node(node); + for (i = 0; i < XA_CHUNK_SIZE; i++) + xa_dump_entry(node->slots[i], + index + (i << node->shift), node->shift); + } + } else if (xa_is_value(entry)) + pr_cont("value %ld (0x%lx) [%px]\n", xa_to_value(entry), + xa_to_value(entry), entry); + else if (!xa_is_internal(entry)) + pr_cont("%px\n", entry); + else if (xa_is_retry(entry)) + pr_cont("retry (%ld)\n", xa_to_internal(entry)); + else if (xa_is_sibling(entry)) + pr_cont("sibling (slot %ld)\n", xa_to_sibling(entry)); + else + pr_cont("UNKNOWN ENTRY (%px)\n", entry); +} + +void xa_dump(const struct xarray *xa) +{ + void *entry = xa->xa_head; + unsigned int shift = 0; + + pr_info("xarray: %px head %px flags %x marks %d %d %d\n", xa, entry, + xa->xa_flags, radix_tree_tagged(xa, 0), + radix_tree_tagged(xa, 1), radix_tree_tagged(xa, 2)); + if (xa_is_node(entry)) + shift = xa_to_node(entry)->shift + XA_CHUNK_SHIFT; + xa_dump_entry(entry, 0, shift); +} +#endif diff --git a/tools/include/linux/kernel.h b/tools/include/linux/kernel.h index 0ad884452c5c..6935ef94e77a 100644 --- a/tools/include/linux/kernel.h +++ b/tools/include/linux/kernel.h @@ -70,6 +70,7 @@ #define BUG_ON(cond) assert(!(cond)) #endif #endif +#define BUG() BUG_ON(1) #if __BYTE_ORDER == __BIG_ENDIAN #define cpu_to_le16 bswap_16 diff --git a/tools/testing/radix-tree/.gitignore b/tools/testing/radix-tree/.gitignore index d4706c0ffceb..3834899b6693 100644 --- a/tools/testing/radix-tree/.gitignore +++ b/tools/testing/radix-tree/.gitignore @@ -4,3 +4,4 @@ idr-test main multiorder radix-tree.c +xarray diff --git a/tools/testing/radix-tree/Makefile b/tools/testing/radix-tree/Makefile index c0cf1c79efd5..1379f1d78d0b 100644 --- a/tools/testing/radix-tree/Makefile +++ b/tools/testing/radix-tree/Makefile @@ -4,7 +4,7 @@ CFLAGS += -I. -I../../include -g -Og -Wall -D_LGPL_SOURCE -fsanitize=address \ -fsanitize=undefined LDFLAGS += -fsanitize=address -fsanitize=undefined LDLIBS+= -lpthread -lurcu -TARGETS = main idr-test multiorder +TARGETS = main idr-test multiorder xarray CORE_OFILES := xarray.o radix-tree.o idr.o linux.o test.o find_bit.o OFILES = main.o $(CORE_OFILES) regression1.o regression2.o regression3.o \ tag_check.o multiorder.o idr-test.o iteration_check.o benchmark.o @@ -25,6 +25,8 @@ main: $(OFILES) idr-test.o: ../../../lib/test_ida.c idr-test: idr-test.o $(CORE_OFILES) +xarray: $(CORE_OFILES) + multiorder: multiorder.o $(CORE_OFILES) clean: @@ -45,7 +47,7 @@ radix-tree.c: ../../../lib/radix-tree.c idr.c: ../../../lib/idr.c sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@ -xarray.o: ../../../lib/xarray.c +xarray.o: ../../../lib/xarray.c ../../../lib/test_xarray.c generated/map-shift.h: @if ! grep -qws $(SHIFT) generated/map-shift.h; then \ diff --git a/tools/testing/radix-tree/linux/kernel.h b/tools/testing/radix-tree/linux/kernel.h index 426f32f28547..5d06ac75a14d 100644 --- a/tools/testing/radix-tree/linux/kernel.h +++ b/tools/testing/radix-tree/linux/kernel.h @@ -14,6 +14,7 @@ #include "../../../include/linux/kconfig.h" #define printk printf +#define pr_info printk #define pr_debug printk #define pr_cont printk diff --git a/tools/testing/radix-tree/linux/rcupdate.h b/tools/testing/radix-tree/linux/rcupdate.h index 73ed33658203..fd280b070fdb 100644 --- a/tools/testing/radix-tree/linux/rcupdate.h +++ b/tools/testing/radix-tree/linux/rcupdate.h @@ -6,5 +6,7 @@ #define rcu_dereference_raw(p) rcu_dereference(p) #define rcu_dereference_protected(p, cond) rcu_dereference(p) +#define rcu_dereference_check(p, cond) rcu_dereference(p) +#define RCU_INIT_POINTER(p, v) (p) = (v) #endif diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c index b741686e53d6..09deaf4f0959 100644 --- a/tools/testing/radix-tree/main.c +++ b/tools/testing/radix-tree/main.c @@ -365,6 +365,7 @@ int main(int argc, char **argv) rcu_register_thread(); radix_tree_init(); + xarray_tests(); regression1_test(); regression2_test(); regression3_test(); diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h index 92d901eacf49..e3dc7a16f09b 100644 --- a/tools/testing/radix-tree/test.h +++ b/tools/testing/radix-tree/test.h @@ -34,6 +34,7 @@ int tag_tagged_items(struct radix_tree_root *, pthread_mutex_t *, unsigned iftag, unsigned thentag); unsigned long find_item(struct radix_tree_root *, void *item); +void xarray_tests(void); void tag_check(void); void multiorder_checks(void); void iteration_test(unsigned order, unsigned duration); diff --git a/tools/testing/radix-tree/xarray.c b/tools/testing/radix-tree/xarray.c index 9bbd667172a7..e61e43efe463 100644 --- a/tools/testing/radix-tree/xarray.c +++ b/tools/testing/radix-tree/xarray.c @@ -4,4 +4,32 @@ * Copyright (c) 2018 Matthew Wilcox */ +#define XA_DEBUG +#include "test.h" + +#define module_init(x) +#define module_exit(x) +#define MODULE_AUTHOR(x) +#define MODULE_LICENSE(x) +#define dump_stack() assert(0) + #include "../../../lib/xarray.c" +#undef XA_DEBUG +#include "../../../lib/test_xarray.c" + +void xarray_tests(void) +{ + xarray_checks(); + xarray_exit(); +} + +int __weak main(void) +{ + radix_tree_init(); + xarray_tests(); + radix_tree_cpu_dead(1); + rcu_barrier(); + if (nr_allocated) + printf("nr_allocated = %d\n", nr_allocated); + return 0; +} -- cgit v1.2.3 From 9b89a0355144685a787b0dc5bcf7bdd6f2d02968 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 10 Nov 2017 09:34:31 -0500 Subject: xarray: Add XArray marks XArray marks are like the radix tree tags, only slightly more strongly typed. They are renamed in order to distinguish them from tagged pointers. This commit adds the basic get/set/clear operations. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 63 +++++++ lib/test_xarray.c | 34 ++++ lib/xarray.c | 232 +++++++++++++++++++++++++- tools/include/asm-generic/bitops.h | 1 + tools/include/asm-generic/bitops/atomic.h | 9 - tools/include/asm-generic/bitops/non-atomic.h | 109 ++++++++++++ tools/include/linux/spinlock.h | 10 +- 7 files changed, 445 insertions(+), 13 deletions(-) create mode 100644 tools/include/asm-generic/bitops/non-atomic.h (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index a0df8217068c..2de504ae9ba4 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -11,6 +11,7 @@ #include #include +#include #include #include #include @@ -197,6 +198,20 @@ static inline int xa_err(void *entry) return 0; } +typedef unsigned __bitwise xa_mark_t; +#define XA_MARK_0 ((__force xa_mark_t)0U) +#define XA_MARK_1 ((__force xa_mark_t)1U) +#define XA_MARK_2 ((__force xa_mark_t)2U) +#define XA_PRESENT ((__force xa_mark_t)8U) +#define XA_MARK_MAX XA_MARK_2 + +/* + * Values for xa_flags. The radix tree stores its GFP flags in the xa_flags, + * and we remain compatible with that. + */ +#define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \ + (__force unsigned)(mark))) + /** * struct xarray - The anchor of the XArray. * @xa_lock: Lock that protects the contents of the XArray. @@ -252,6 +267,9 @@ struct xarray { void xa_init_flags(struct xarray *, gfp_t flags); void *xa_load(struct xarray *, unsigned long index); +bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); +void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); +void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); /** * xa_init() - Initialise an empty XArray. @@ -278,6 +296,19 @@ static inline bool xa_empty(const struct xarray *xa) return xa->xa_head == NULL; } +/** + * xa_marked() - Inquire whether any entry in this array has a mark set + * @xa: Array + * @mark: Mark value + * + * Context: Any context. + * Return: %true if any entry has this mark set. + */ +static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) +{ + return xa->xa_flags & XA_FLAGS_MARK(mark); +} + #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) #define xa_lock(xa) spin_lock(&(xa)->xa_lock) #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) @@ -290,6 +321,12 @@ static inline bool xa_empty(const struct xarray *xa) #define xa_unlock_irqrestore(xa, flags) \ spin_unlock_irqrestore(&(xa)->xa_lock, flags) +/* + * Versions of the normal API which require the caller to hold the xa_lock. + */ +void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); +void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); + /* Everything below here is the Advanced API. Proceed with caution. */ /* @@ -388,6 +425,22 @@ static inline void *xa_entry_locked(const struct xarray *xa, lockdep_is_held(&xa->xa_lock)); } +/* Private */ +static inline struct xa_node *xa_parent(const struct xarray *xa, + const struct xa_node *node) +{ + return rcu_dereference_check(node->parent, + lockdep_is_held(&xa->xa_lock)); +} + +/* Private */ +static inline struct xa_node *xa_parent_locked(const struct xarray *xa, + const struct xa_node *node) +{ + return rcu_dereference_protected(node->parent, + lockdep_is_held(&xa->xa_lock)); +} + /* Private */ static inline struct xa_node *xa_to_node(const void *entry) { @@ -588,6 +641,12 @@ static inline bool xas_valid(const struct xa_state *xas) return !xas_invalid(xas); } +/* True if the pointer is something other than a node */ +static inline bool xas_not_node(struct xa_node *node) +{ + return ((unsigned long)node & 3) || !node; +} + /** * xas_reset() - Reset an XArray operation state. * @xas: XArray operation state. @@ -625,6 +684,10 @@ static inline bool xas_retry(struct xa_state *xas, const void *entry) void *xas_load(struct xa_state *); +bool xas_get_mark(const struct xa_state *, xa_mark_t); +void xas_set_mark(const struct xa_state *, xa_mark_t); +void xas_clear_mark(const struct xa_state *, xa_mark_t); + /** * xas_reload() - Refetch an entry from the xarray. * @xas: XArray operation state. diff --git a/lib/test_xarray.c b/lib/test_xarray.c index a7248b87617f..f8b0e9ba80a4 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -67,11 +67,45 @@ static noinline void check_xa_load(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_xa_mark_1(struct xarray *xa, unsigned long index) +{ + /* NULL elements have no marks set */ + XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); + xa_set_mark(xa, index, XA_MARK_0); + XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); + + /* Storing a pointer will not make a mark appear */ + XA_BUG_ON(xa, xa_store_index(xa, index, GFP_KERNEL) != NULL); + XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); + xa_set_mark(xa, index, XA_MARK_0); + XA_BUG_ON(xa, !xa_get_mark(xa, index, XA_MARK_0)); + + /* Setting one mark will not set another mark */ + XA_BUG_ON(xa, xa_get_mark(xa, index + 1, XA_MARK_0)); + XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_1)); + + /* Storing NULL clears marks, and they can't be set again */ + xa_erase_index(xa, index); + XA_BUG_ON(xa, !xa_empty(xa)); + XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); + xa_set_mark(xa, index, XA_MARK_0); + XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); +} + +static noinline void check_xa_mark(struct xarray *xa) +{ + unsigned long index; + + for (index = 0; index < 16384; index += 4) + check_xa_mark_1(xa, index); +} + static RADIX_TREE(array, GFP_KERNEL); static int xarray_checks(void) { check_xa_load(&array); + check_xa_mark(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run == tests_passed) ? 0 : -EINVAL; diff --git a/lib/xarray.c b/lib/xarray.c index 19cfcbc69a68..aa86c47e532f 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -5,6 +5,7 @@ * Author: Matthew Wilcox */ +#include #include #include @@ -24,6 +25,48 @@ * @entry refers to something stored in a slot in the xarray */ +static inline void xa_mark_set(struct xarray *xa, xa_mark_t mark) +{ + if (!(xa->xa_flags & XA_FLAGS_MARK(mark))) + xa->xa_flags |= XA_FLAGS_MARK(mark); +} + +static inline void xa_mark_clear(struct xarray *xa, xa_mark_t mark) +{ + if (xa->xa_flags & XA_FLAGS_MARK(mark)) + xa->xa_flags &= ~(XA_FLAGS_MARK(mark)); +} + +static inline unsigned long *node_marks(struct xa_node *node, xa_mark_t mark) +{ + return node->marks[(__force unsigned)mark]; +} + +static inline bool node_get_mark(struct xa_node *node, + unsigned int offset, xa_mark_t mark) +{ + return test_bit(offset, node_marks(node, mark)); +} + +/* returns true if the bit was set */ +static inline bool node_set_mark(struct xa_node *node, unsigned int offset, + xa_mark_t mark) +{ + return __test_and_set_bit(offset, node_marks(node, mark)); +} + +/* returns true if the bit was set */ +static inline bool node_clear_mark(struct xa_node *node, unsigned int offset, + xa_mark_t mark) +{ + return __test_and_clear_bit(offset, node_marks(node, mark)); +} + +static inline bool node_any_mark(struct xa_node *node, xa_mark_t mark) +{ + return !bitmap_empty(node_marks(node, mark), XA_CHUNK_SIZE); +} + /* extracts the offset within this node from the index */ static unsigned int get_offset(unsigned long index, struct xa_node *node) { @@ -118,6 +161,85 @@ void *xas_load(struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_load); +/** + * xas_get_mark() - Returns the state of this mark. + * @xas: XArray operation state. + * @mark: Mark number. + * + * Return: true if the mark is set, false if the mark is clear or @xas + * is in an error state. + */ +bool xas_get_mark(const struct xa_state *xas, xa_mark_t mark) +{ + if (xas_invalid(xas)) + return false; + if (!xas->xa_node) + return xa_marked(xas->xa, mark); + return node_get_mark(xas->xa_node, xas->xa_offset, mark); +} +EXPORT_SYMBOL_GPL(xas_get_mark); + +/** + * xas_set_mark() - Sets the mark on this entry and its parents. + * @xas: XArray operation state. + * @mark: Mark number. + * + * Sets the specified mark on this entry, and walks up the tree setting it + * on all the ancestor entries. Does nothing if @xas has not been walked to + * an entry, or is in an error state. + */ +void xas_set_mark(const struct xa_state *xas, xa_mark_t mark) +{ + struct xa_node *node = xas->xa_node; + unsigned int offset = xas->xa_offset; + + if (xas_invalid(xas)) + return; + + while (node) { + if (node_set_mark(node, offset, mark)) + return; + offset = node->offset; + node = xa_parent_locked(xas->xa, node); + } + + if (!xa_marked(xas->xa, mark)) + xa_mark_set(xas->xa, mark); +} +EXPORT_SYMBOL_GPL(xas_set_mark); + +/** + * xas_clear_mark() - Clears the mark on this entry and its parents. + * @xas: XArray operation state. + * @mark: Mark number. + * + * Clears the specified mark on this entry, and walks back to the head + * attempting to clear it on all the ancestor entries. Does nothing if + * @xas has not been walked to an entry, or is in an error state. + */ +void xas_clear_mark(const struct xa_state *xas, xa_mark_t mark) +{ + struct xa_node *node = xas->xa_node; + unsigned int offset = xas->xa_offset; + + if (xas_invalid(xas)) + return; + + while (node) { + if (!node_clear_mark(node, offset, mark)) + return; + if (node_any_mark(node, mark)) + return; + + offset = node->offset; + node = xa_parent_locked(xas->xa, node); + } + + if (xa_marked(xas->xa, mark)) + xa_mark_clear(xas->xa, mark); +} +EXPORT_SYMBOL_GPL(xas_clear_mark); + /** * xa_init_flags() - Initialise an empty XArray with flags. * @xa: XArray. @@ -160,6 +282,112 @@ void *xa_load(struct xarray *xa, unsigned long index) } EXPORT_SYMBOL(xa_load); +/** + * __xa_set_mark() - Set this mark on this entry while locked. + * @xa: XArray. + * @index: Index of entry. + * @mark: Mark number. + * + * Attempting to set a mark on a NULL entry does not succeed. + * + * Context: Any context. Expects xa_lock to be held on entry. + */ +void __xa_set_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) +{ + XA_STATE(xas, xa, index); + void *entry = xas_load(&xas); + + if (entry) + xas_set_mark(&xas, mark); +} +EXPORT_SYMBOL_GPL(__xa_set_mark); + +/** + * __xa_clear_mark() - Clear this mark on this entry while locked. + * @xa: XArray. + * @index: Index of entry. + * @mark: Mark number. + * + * Context: Any context. Expects xa_lock to be held on entry. + */ +void __xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) +{ + XA_STATE(xas, xa, index); + void *entry = xas_load(&xas); + + if (entry) + xas_clear_mark(&xas, mark); +} +EXPORT_SYMBOL_GPL(__xa_clear_mark); + +/** + * xa_get_mark() - Inquire whether this mark is set on this entry. + * @xa: XArray. + * @index: Index of entry. + * @mark: Mark number. + * + * This function uses the RCU read lock, so the result may be out of date + * by the time it returns. If you need the result to be stable, use a lock. + * + * Context: Any context. Takes and releases the RCU lock. + * Return: True if the entry at @index has this mark set, false if it doesn't. + */ +bool xa_get_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) +{ + XA_STATE(xas, xa, index); + void *entry; + + rcu_read_lock(); + entry = xas_start(&xas); + while (xas_get_mark(&xas, mark)) { + if (!xa_is_node(entry)) + goto found; + entry = xas_descend(&xas, xa_to_node(entry)); + } + rcu_read_unlock(); + return false; + found: + rcu_read_unlock(); + return true; +} +EXPORT_SYMBOL(xa_get_mark); + +/** + * xa_set_mark() - Set this mark on this entry. + * @xa: XArray. + * @index: Index of entry. + * @mark: Mark number. + * + * Attempting to set a mark on a NULL entry does not succeed. + * + * Context: Process context. Takes and releases the xa_lock. + */ +void xa_set_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) +{ + xa_lock(xa); + __xa_set_mark(xa, index, mark); + xa_unlock(xa); +} +EXPORT_SYMBOL(xa_set_mark); + +/** + * xa_clear_mark() - Clear this mark on this entry. + * @xa: XArray. + * @index: Index of entry. + * @mark: Mark number. + * + * Clearing a mark always succeeds. + * + * Context: Process context. Takes and releases the xa_lock. + */ +void xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) +{ + xa_lock(xa); + __xa_clear_mark(xa, index, mark); + xa_unlock(xa); +} +EXPORT_SYMBOL(xa_clear_mark); + #ifdef XA_DEBUG void xa_dump_node(const struct xa_node *node) { @@ -230,8 +458,8 @@ void xa_dump(const struct xarray *xa) unsigned int shift = 0; pr_info("xarray: %px head %px flags %x marks %d %d %d\n", xa, entry, - xa->xa_flags, radix_tree_tagged(xa, 0), - radix_tree_tagged(xa, 1), radix_tree_tagged(xa, 2)); + xa->xa_flags, xa_marked(xa, XA_MARK_0), + xa_marked(xa, XA_MARK_1), xa_marked(xa, XA_MARK_2)); if (xa_is_node(entry)) shift = xa_to_node(entry)->shift + XA_CHUNK_SHIFT; xa_dump_entry(entry, 0, shift); diff --git a/tools/include/asm-generic/bitops.h b/tools/include/asm-generic/bitops.h index 9bce3b56b5e7..5d2ab38965cc 100644 --- a/tools/include/asm-generic/bitops.h +++ b/tools/include/asm-generic/bitops.h @@ -27,5 +27,6 @@ #include #include +#include #endif /* __TOOLS_ASM_GENERIC_BITOPS_H */ diff --git a/tools/include/asm-generic/bitops/atomic.h b/tools/include/asm-generic/bitops/atomic.h index 21c41ccd1266..2f6ea28764a7 100644 --- a/tools/include/asm-generic/bitops/atomic.h +++ b/tools/include/asm-generic/bitops/atomic.h @@ -15,13 +15,4 @@ static inline void clear_bit(int nr, unsigned long *addr) addr[nr / __BITS_PER_LONG] &= ~(1UL << (nr % __BITS_PER_LONG)); } -static __always_inline int test_bit(unsigned int nr, const unsigned long *addr) -{ - return ((1UL << (nr % __BITS_PER_LONG)) & - (((unsigned long *)addr)[nr / __BITS_PER_LONG])) != 0; -} - -#define __set_bit(nr, addr) set_bit(nr, addr) -#define __clear_bit(nr, addr) clear_bit(nr, addr) - #endif /* _TOOLS_LINUX_ASM_GENERIC_BITOPS_ATOMIC_H_ */ diff --git a/tools/include/asm-generic/bitops/non-atomic.h b/tools/include/asm-generic/bitops/non-atomic.h new file mode 100644 index 000000000000..7e10c4b50c5d --- /dev/null +++ b/tools/include/asm-generic/bitops/non-atomic.h @@ -0,0 +1,109 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ +#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ + +#include + +/** + * __set_bit - Set a bit in memory + * @nr: the bit to set + * @addr: the address to start counting from + * + * Unlike set_bit(), this function is non-atomic and may be reordered. + * If it's called on the same region of memory simultaneously, the effect + * may be that only one operation succeeds. + */ +static inline void __set_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + + *p |= mask; +} + +static inline void __clear_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + + *p &= ~mask; +} + +/** + * __change_bit - Toggle a bit in memory + * @nr: the bit to change + * @addr: the address to start counting from + * + * Unlike change_bit(), this function is non-atomic and may be reordered. + * If it's called on the same region of memory simultaneously, the effect + * may be that only one operation succeeds. + */ +static inline void __change_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + + *p ^= mask; +} + +/** + * __test_and_set_bit - Set a bit and return its old value + * @nr: Bit to set + * @addr: Address to count from + * + * This operation is non-atomic and can be reordered. + * If two examples of this operation race, one can appear to succeed + * but actually fail. You must protect multiple accesses with a lock. + */ +static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + unsigned long old = *p; + + *p = old | mask; + return (old & mask) != 0; +} + +/** + * __test_and_clear_bit - Clear a bit and return its old value + * @nr: Bit to clear + * @addr: Address to count from + * + * This operation is non-atomic and can be reordered. + * If two examples of this operation race, one can appear to succeed + * but actually fail. You must protect multiple accesses with a lock. + */ +static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + unsigned long old = *p; + + *p = old & ~mask; + return (old & mask) != 0; +} + +/* WARNING: non atomic and it can be reordered! */ +static inline int __test_and_change_bit(int nr, + volatile unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); + unsigned long old = *p; + + *p = old ^ mask; + return (old & mask) != 0; +} + +/** + * test_bit - Determine whether a bit is set + * @nr: bit number to test + * @addr: Address to start counting from + */ +static inline int test_bit(int nr, const volatile unsigned long *addr) +{ + return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); +} + +#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */ diff --git a/tools/include/linux/spinlock.h b/tools/include/linux/spinlock.h index 1738c0391da4..622266b197d0 100644 --- a/tools/include/linux/spinlock.h +++ b/tools/include/linux/spinlock.h @@ -8,8 +8,14 @@ #define spinlock_t pthread_mutex_t #define DEFINE_SPINLOCK(x) pthread_mutex_t x = PTHREAD_MUTEX_INITIALIZER #define __SPIN_LOCK_UNLOCKED(x) (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER -#define spin_lock_init(x) pthread_mutex_init(x, NULL) - +#define spin_lock_init(x) pthread_mutex_init(x, NULL) + +#define spin_lock(x) pthread_mutex_lock(x) +#define spin_unlock(x) pthread_mutex_unlock(x) +#define spin_lock_bh(x) pthread_mutex_lock(x) +#define spin_unlock_bh(x) pthread_mutex_unlock(x) +#define spin_lock_irq(x) pthread_mutex_lock(x) +#define spin_unlock_irq(x) pthread_mutex_unlock(x) #define spin_lock_irqsave(x, f) (void)f, pthread_mutex_lock(x) #define spin_unlock_irqrestore(x, f) (void)f, pthread_mutex_unlock(x) -- cgit v1.2.3 From 58d6ea3085f2e53714810a513c61629f6d2be0a6 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 10 Nov 2017 15:15:08 -0500 Subject: xarray: Add XArray unconditional store operations xa_store() differs from radix_tree_insert() in that it will overwrite an existing element in the array rather than returning an error. This is the behaviour which most users want, and those that want more complex behaviour generally want to use the xas family of routines anyway. For memory allocation, xa_store() will first attempt to request memory from the slab allocator; if memory is not immediately available, it will drop the xa_lock and allocate memory, keeping a pointer in the xa_state. It does not use the per-CPU cache, although those will continue to exist until all radix tree users are converted to the xarray. This patch also includes xa_erase() and __xa_erase() for a streamlined way to store NULL. Since there is no need to allocate memory in order to store a NULL in the XArray, we do not need to trouble the user with deciding what memory allocation flags to use. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 147 ++++++- lib/radix-tree.c | 4 +- lib/test_xarray.c | 177 +++++++- lib/xarray.c | 693 +++++++++++++++++++++++++++++++ tools/include/linux/bitmap.h | 1 + tools/include/linux/spinlock.h | 2 + tools/testing/radix-tree/Makefile | 2 +- tools/testing/radix-tree/bitmap.c | 23 + tools/testing/radix-tree/linux/kernel.h | 4 + tools/testing/radix-tree/linux/lockdep.h | 11 + 10 files changed, 1055 insertions(+), 9 deletions(-) create mode 100644 tools/testing/radix-tree/bitmap.c create mode 100644 tools/testing/radix-tree/linux/lockdep.h (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 2de504ae9ba4..15eab63286ed 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -205,10 +205,17 @@ typedef unsigned __bitwise xa_mark_t; #define XA_PRESENT ((__force xa_mark_t)8U) #define XA_MARK_MAX XA_MARK_2 +enum xa_lock_type { + XA_LOCK_IRQ = 1, + XA_LOCK_BH = 2, +}; + /* * Values for xa_flags. The radix tree stores its GFP flags in the xa_flags, * and we remain compatible with that. */ +#define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ) +#define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH) #define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \ (__force unsigned)(mark))) @@ -267,6 +274,7 @@ struct xarray { void xa_init_flags(struct xarray *, gfp_t flags); void *xa_load(struct xarray *, unsigned long index); +void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); @@ -309,6 +317,23 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) return xa->xa_flags & XA_FLAGS_MARK(mark); } +/** + * xa_erase() - Erase this entry from the XArray. + * @xa: XArray. + * @index: Index of entry. + * + * This function is the equivalent of calling xa_store() with %NULL as + * the third argument. The XArray does not need to allocate memory, so + * the user does not need to provide GFP flags. + * + * Context: Process context. Takes and releases the xa_lock. + * Return: The entry which used to be at this index. + */ +static inline void *xa_erase(struct xarray *xa, unsigned long index) +{ + return xa_store(xa, index, NULL, 0); +} + #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) #define xa_lock(xa) spin_lock(&(xa)->xa_lock) #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) @@ -322,11 +347,65 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) spin_unlock_irqrestore(&(xa)->xa_lock, flags) /* - * Versions of the normal API which require the caller to hold the xa_lock. - */ + * Versions of the normal API which require the caller to hold the + * xa_lock. If the GFP flags allow it, they will drop the lock to + * allocate memory, then reacquire it afterwards. These functions + * may also re-enable interrupts if the XArray flags indicate the + * locking should be interrupt safe. + */ +void *__xa_erase(struct xarray *, unsigned long index); +void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); +/** + * xa_erase_bh() - Erase this entry from the XArray. + * @xa: XArray. + * @index: Index of entry. + * + * This function is the equivalent of calling xa_store() with %NULL as + * the third argument. The XArray does not need to allocate memory, so + * the user does not need to provide GFP flags. + * + * Context: Process context. Takes and releases the xa_lock while + * disabling softirqs. + * Return: The entry which used to be at this index. + */ +static inline void *xa_erase_bh(struct xarray *xa, unsigned long index) +{ + void *entry; + + xa_lock_bh(xa); + entry = __xa_erase(xa, index); + xa_unlock_bh(xa); + + return entry; +} + +/** + * xa_erase_irq() - Erase this entry from the XArray. + * @xa: XArray. + * @index: Index of entry. + * + * This function is the equivalent of calling xa_store() with %NULL as + * the third argument. The XArray does not need to allocate memory, so + * the user does not need to provide GFP flags. + * + * Context: Process context. Takes and releases the xa_lock while + * disabling interrupts. + * Return: The entry which used to be at this index. + */ +static inline void *xa_erase_irq(struct xarray *xa, unsigned long index) +{ + void *entry; + + xa_lock_irq(xa); + entry = __xa_erase(xa, index); + xa_unlock_irq(xa); + + return entry; +} + /* Everything below here is the Advanced API. Proceed with caution. */ /* @@ -441,6 +520,12 @@ static inline struct xa_node *xa_parent_locked(const struct xarray *xa, lockdep_is_held(&xa->xa_lock)); } +/* Private */ +static inline void *xa_mk_node(const struct xa_node *node) +{ + return (void *)((unsigned long)node | 2); +} + /* Private */ static inline struct xa_node *xa_to_node(const void *entry) { @@ -647,6 +732,12 @@ static inline bool xas_not_node(struct xa_node *node) return ((unsigned long)node & 3) || !node; } +/* True if the node represents head-of-tree, RESTART or BOUNDS */ +static inline bool xas_top(struct xa_node *node) +{ + return node <= XAS_RESTART; +} + /** * xas_reset() - Reset an XArray operation state. * @xas: XArray operation state. @@ -683,10 +774,14 @@ static inline bool xas_retry(struct xa_state *xas, const void *entry) } void *xas_load(struct xa_state *); +void *xas_store(struct xa_state *, void *entry); bool xas_get_mark(const struct xa_state *, xa_mark_t); void xas_set_mark(const struct xa_state *, xa_mark_t); void xas_clear_mark(const struct xa_state *, xa_mark_t); +void xas_init_marks(const struct xa_state *); + +bool xas_nomem(struct xa_state *, gfp_t); /** * xas_reload() - Refetch an entry from the xarray. @@ -711,4 +806,52 @@ static inline void *xas_reload(struct xa_state *xas) return xa_head(xas->xa); } +/** + * xas_set() - Set up XArray operation state for a different index. + * @xas: XArray operation state. + * @index: New index into the XArray. + * + * Move the operation state to refer to a different index. This will + * have the effect of starting a walk from the top; see xas_next() + * to move to an adjacent index. + */ +static inline void xas_set(struct xa_state *xas, unsigned long index) +{ + xas->xa_index = index; + xas->xa_node = XAS_RESTART; +} + +/** + * xas_set_order() - Set up XArray operation state for a multislot entry. + * @xas: XArray operation state. + * @index: Target of the operation. + * @order: Entry occupies 2^@order indices. + */ +static inline void xas_set_order(struct xa_state *xas, unsigned long index, + unsigned int order) +{ +#ifdef CONFIG_XARRAY_MULTI + xas->xa_index = order < BITS_PER_LONG ? (index >> order) << order : 0; + xas->xa_shift = order - (order % XA_CHUNK_SHIFT); + xas->xa_sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; + xas->xa_node = XAS_RESTART; +#else + BUG_ON(order > 0); + xas_set(xas, index); +#endif +} + +/** + * xas_set_update() - Set up XArray operation state for a callback. + * @xas: XArray operation state. + * @update: Function to call when updating a node. + * + * The XArray can notify a caller after it has updated an xa_node. + * This is advanced functionality and is only needed by the page cache. + */ +static inline void xas_set_update(struct xa_state *xas, xa_update_node_t update) +{ + xas->xa_update = update; +} + #endif /* _LINUX_XARRAY_H */ diff --git a/lib/radix-tree.c b/lib/radix-tree.c index b8e961428484..3479d93c32b9 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -47,7 +47,7 @@ static unsigned long height_to_maxnodes[RADIX_TREE_MAX_PATH + 1] __read_mostly; /* * Radix tree node cache. */ -static struct kmem_cache *radix_tree_node_cachep; +struct kmem_cache *radix_tree_node_cachep; /* * The radix tree is variable-height, so an insert operation not only has @@ -365,7 +365,7 @@ out: return ret; } -static void radix_tree_node_rcu_free(struct rcu_head *head) +void radix_tree_node_rcu_free(struct rcu_head *head) { struct radix_tree_node *node = container_of(head, struct radix_tree_node, rcu_head); diff --git a/lib/test_xarray.c b/lib/test_xarray.c index f8b0e9ba80a4..b711030fbc32 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -30,13 +30,49 @@ void xa_dump(const struct xarray *xa) { } static void *xa_store_index(struct xarray *xa, unsigned long index, gfp_t gfp) { - radix_tree_insert(xa, index, xa_mk_value(index)); - return NULL; + return xa_store(xa, index, xa_mk_value(index & LONG_MAX), gfp); } static void xa_erase_index(struct xarray *xa, unsigned long index) { - radix_tree_delete(xa, index); + XA_BUG_ON(xa, xa_erase(xa, index) != xa_mk_value(index & LONG_MAX)); + XA_BUG_ON(xa, xa_load(xa, index) != NULL); +} + +/* + * If anyone needs this, please move it to xarray.c. We have no current + * users outside the test suite because all current multislot users want + * to use the advanced API. + */ +static void *xa_store_order(struct xarray *xa, unsigned long index, + unsigned order, void *entry, gfp_t gfp) +{ + XA_STATE_ORDER(xas, xa, index, order); + void *curr; + + do { + xas_lock(&xas); + curr = xas_store(&xas, entry); + xas_unlock(&xas); + } while (xas_nomem(&xas, gfp)); + + return curr; +} + +static noinline void check_xa_err(struct xarray *xa) +{ + XA_BUG_ON(xa, xa_err(xa_store_index(xa, 0, GFP_NOWAIT)) != 0); + XA_BUG_ON(xa, xa_err(xa_erase(xa, 0)) != 0); +#ifndef __KERNEL__ + /* The kernel does not fail GFP_NOWAIT allocations */ + XA_BUG_ON(xa, xa_err(xa_store_index(xa, 1, GFP_NOWAIT)) != -ENOMEM); + XA_BUG_ON(xa, xa_err(xa_store_index(xa, 1, GFP_NOWAIT)) != -ENOMEM); +#endif + XA_BUG_ON(xa, xa_err(xa_store_index(xa, 1, GFP_KERNEL)) != 0); + XA_BUG_ON(xa, xa_err(xa_store(xa, 1, xa_mk_value(0), GFP_KERNEL)) != 0); + XA_BUG_ON(xa, xa_err(xa_erase(xa, 1)) != 0); +// kills the test-suite :-( +// XA_BUG_ON(xa, xa_err(xa_store(xa, 0, xa_mk_internal(0), 0)) != -EINVAL); } static noinline void check_xa_load(struct xarray *xa) @@ -69,6 +105,9 @@ static noinline void check_xa_load(struct xarray *xa) static noinline void check_xa_mark_1(struct xarray *xa, unsigned long index) { + unsigned int order; + unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 8 : 1; + /* NULL elements have no marks set */ XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); xa_set_mark(xa, index, XA_MARK_0); @@ -90,6 +129,37 @@ static noinline void check_xa_mark_1(struct xarray *xa, unsigned long index) XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); xa_set_mark(xa, index, XA_MARK_0); XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0)); + + /* + * Storing a multi-index entry over entries with marks gives the + * entire entry the union of the marks + */ + BUG_ON((index % 4) != 0); + for (order = 2; order < max_order; order++) { + unsigned long base = round_down(index, 1UL << order); + unsigned long next = base + (1UL << order); + unsigned long i; + + XA_BUG_ON(xa, xa_store_index(xa, index + 1, GFP_KERNEL)); + xa_set_mark(xa, index + 1, XA_MARK_0); + XA_BUG_ON(xa, xa_store_index(xa, index + 2, GFP_KERNEL)); + xa_set_mark(xa, index + 2, XA_MARK_1); + XA_BUG_ON(xa, xa_store_index(xa, next, GFP_KERNEL)); + xa_store_order(xa, index, order, xa_mk_value(index), + GFP_KERNEL); + for (i = base; i < next; i++) { + XA_BUG_ON(xa, !xa_get_mark(xa, i, XA_MARK_0)); + XA_BUG_ON(xa, !xa_get_mark(xa, i, XA_MARK_1)); + XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_2)); + } + XA_BUG_ON(xa, xa_get_mark(xa, next, XA_MARK_0)); + XA_BUG_ON(xa, xa_get_mark(xa, next, XA_MARK_1)); + XA_BUG_ON(xa, xa_get_mark(xa, next, XA_MARK_2)); + xa_erase_index(xa, index); + xa_erase_index(xa, next); + XA_BUG_ON(xa, !xa_empty(xa)); + } + XA_BUG_ON(xa, !xa_empty(xa)); } static noinline void check_xa_mark(struct xarray *xa) @@ -100,12 +170,111 @@ static noinline void check_xa_mark(struct xarray *xa) check_xa_mark_1(xa, index); } -static RADIX_TREE(array, GFP_KERNEL); +static noinline void check_xa_shrink(struct xarray *xa) +{ + XA_STATE(xas, xa, 1); + struct xa_node *node; + + XA_BUG_ON(xa, !xa_empty(xa)); + XA_BUG_ON(xa, xa_store_index(xa, 0, GFP_KERNEL) != NULL); + XA_BUG_ON(xa, xa_store_index(xa, 1, GFP_KERNEL) != NULL); + + /* + * Check that erasing the entry at 1 shrinks the tree and properly + * marks the node as being deleted. + */ + xas_lock(&xas); + XA_BUG_ON(xa, xas_load(&xas) != xa_mk_value(1)); + node = xas.xa_node; + XA_BUG_ON(xa, xa_entry_locked(xa, node, 0) != xa_mk_value(0)); + XA_BUG_ON(xa, xas_store(&xas, NULL) != xa_mk_value(1)); + XA_BUG_ON(xa, xa_load(xa, 1) != NULL); + XA_BUG_ON(xa, xas.xa_node != XAS_BOUNDS); + XA_BUG_ON(xa, xa_entry_locked(xa, node, 0) != XA_RETRY_ENTRY); + XA_BUG_ON(xa, xas_load(&xas) != NULL); + xas_unlock(&xas); + XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(0)); + xa_erase_index(xa, 0); + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_multi_store(struct xarray *xa) +{ +#ifdef CONFIG_XARRAY_MULTI + unsigned long i, j, k; + unsigned int max_order = (sizeof(long) == 4) ? 30 : 60; + + /* Loading from any position returns the same value */ + xa_store_order(xa, 0, 1, xa_mk_value(0), GFP_KERNEL); + XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(0)); + XA_BUG_ON(xa, xa_load(xa, 1) != xa_mk_value(0)); + XA_BUG_ON(xa, xa_load(xa, 2) != NULL); + rcu_read_lock(); + XA_BUG_ON(xa, xa_to_node(xa_head(xa))->count != 2); + XA_BUG_ON(xa, xa_to_node(xa_head(xa))->nr_values != 2); + rcu_read_unlock(); + + /* Storing adjacent to the value does not alter the value */ + xa_store(xa, 3, xa, GFP_KERNEL); + XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(0)); + XA_BUG_ON(xa, xa_load(xa, 1) != xa_mk_value(0)); + XA_BUG_ON(xa, xa_load(xa, 2) != NULL); + rcu_read_lock(); + XA_BUG_ON(xa, xa_to_node(xa_head(xa))->count != 3); + XA_BUG_ON(xa, xa_to_node(xa_head(xa))->nr_values != 2); + rcu_read_unlock(); + + /* Overwriting multiple indexes works */ + xa_store_order(xa, 0, 2, xa_mk_value(1), GFP_KERNEL); + XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(1)); + XA_BUG_ON(xa, xa_load(xa, 1) != xa_mk_value(1)); + XA_BUG_ON(xa, xa_load(xa, 2) != xa_mk_value(1)); + XA_BUG_ON(xa, xa_load(xa, 3) != xa_mk_value(1)); + XA_BUG_ON(xa, xa_load(xa, 4) != NULL); + rcu_read_lock(); + XA_BUG_ON(xa, xa_to_node(xa_head(xa))->count != 4); + XA_BUG_ON(xa, xa_to_node(xa_head(xa))->nr_values != 4); + rcu_read_unlock(); + + /* We can erase multiple values with a single store */ + xa_store_order(xa, 0, 63, NULL, GFP_KERNEL); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Even when the first slot is empty but the others aren't */ + xa_store_index(xa, 1, GFP_KERNEL); + xa_store_index(xa, 2, GFP_KERNEL); + xa_store_order(xa, 0, 2, NULL, GFP_KERNEL); + XA_BUG_ON(xa, !xa_empty(xa)); + + for (i = 0; i < max_order; i++) { + for (j = 0; j < max_order; j++) { + xa_store_order(xa, 0, i, xa_mk_value(i), GFP_KERNEL); + xa_store_order(xa, 0, j, xa_mk_value(j), GFP_KERNEL); + + for (k = 0; k < max_order; k++) { + void *entry = xa_load(xa, (1UL << k) - 1); + if ((i < k) && (j < k)) + XA_BUG_ON(xa, entry != NULL); + else + XA_BUG_ON(xa, entry != xa_mk_value(j)); + } + + xa_erase(xa, 0); + XA_BUG_ON(xa, !xa_empty(xa)); + } + } +#endif +} + +static DEFINE_XARRAY(array); static int xarray_checks(void) { + check_xa_err(&array); check_xa_load(&array); check_xa_mark(&array); + check_xa_shrink(&array); + check_multi_store(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run == tests_passed) ? 0 : -EINVAL; diff --git a/lib/xarray.c b/lib/xarray.c index aa86c47e532f..4596a95ed9cd 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -7,6 +7,8 @@ #include #include +#include +#include #include /* @@ -25,6 +27,31 @@ * @entry refers to something stored in a slot in the xarray */ +static inline unsigned int xa_lock_type(const struct xarray *xa) +{ + return (__force unsigned int)xa->xa_flags & 3; +} + +static inline void xas_lock_type(struct xa_state *xas, unsigned int lock_type) +{ + if (lock_type == XA_LOCK_IRQ) + xas_lock_irq(xas); + else if (lock_type == XA_LOCK_BH) + xas_lock_bh(xas); + else + xas_lock(xas); +} + +static inline void xas_unlock_type(struct xa_state *xas, unsigned int lock_type) +{ + if (lock_type == XA_LOCK_IRQ) + xas_unlock_irq(xas); + else if (lock_type == XA_LOCK_BH) + xas_unlock_bh(xas); + else + xas_unlock(xas); +} + static inline void xa_mark_set(struct xarray *xa, xa_mark_t mark) { if (!(xa->xa_flags & XA_FLAGS_MARK(mark))) @@ -67,6 +94,34 @@ static inline bool node_any_mark(struct xa_node *node, xa_mark_t mark) return !bitmap_empty(node_marks(node, mark), XA_CHUNK_SIZE); } +#define mark_inc(mark) do { \ + mark = (__force xa_mark_t)((__force unsigned)(mark) + 1); \ +} while (0) + +/* + * xas_squash_marks() - Merge all marks to the first entry + * @xas: Array operation state. + * + * Set a mark on the first entry if any entry has it set. Clear marks on + * all sibling entries. + */ +static void xas_squash_marks(const struct xa_state *xas) +{ + unsigned int mark = 0; + unsigned int limit = xas->xa_offset + xas->xa_sibs + 1; + + if (!xas->xa_sibs) + return; + + do { + unsigned long *marks = xas->xa_node->marks[mark]; + if (find_next_bit(marks, limit, xas->xa_offset + 1) == limit) + continue; + __set_bit(xas->xa_offset, marks); + bitmap_clear(marks, xas->xa_offset + 1, xas->xa_sibs); + } while (mark++ != (__force unsigned)XA_MARK_MAX); +} + /* extracts the offset within this node from the index */ static unsigned int get_offset(unsigned long index, struct xa_node *node) { @@ -161,6 +216,516 @@ void *xas_load(struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_load); +/* Move the radix tree node cache here */ +extern struct kmem_cache *radix_tree_node_cachep; +extern void radix_tree_node_rcu_free(struct rcu_head *head); + +#define XA_RCU_FREE ((struct xarray *)1) + +static void xa_node_free(struct xa_node *node) +{ + XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); + node->array = XA_RCU_FREE; + call_rcu(&node->rcu_head, radix_tree_node_rcu_free); +} + +/* + * xas_destroy() - Free any resources allocated during the XArray operation. + * @xas: XArray operation state. + * + * This function is now internal-only. + */ +static void xas_destroy(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_alloc; + + if (!node) + return; + XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); + kmem_cache_free(radix_tree_node_cachep, node); + xas->xa_alloc = NULL; +} + +/** + * xas_nomem() - Allocate memory if needed. + * @xas: XArray operation state. + * @gfp: Memory allocation flags. + * + * If we need to add new nodes to the XArray, we try to allocate memory + * with GFP_NOWAIT while holding the lock, which will usually succeed. + * If it fails, @xas is flagged as needing memory to continue. The caller + * should drop the lock and call xas_nomem(). If xas_nomem() succeeds, + * the caller should retry the operation. + * + * Forward progress is guaranteed as one node is allocated here and + * stored in the xa_state where it will be found by xas_alloc(). More + * nodes will likely be found in the slab allocator, but we do not tie + * them up here. + * + * Return: true if memory was needed, and was successfully allocated. + */ +bool xas_nomem(struct xa_state *xas, gfp_t gfp) +{ + if (xas->xa_node != XA_ERROR(-ENOMEM)) { + xas_destroy(xas); + return false; + } + xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); + if (!xas->xa_alloc) + return false; + XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); + xas->xa_node = XAS_RESTART; + return true; +} +EXPORT_SYMBOL_GPL(xas_nomem); + +/* + * __xas_nomem() - Drop locks and allocate memory if needed. + * @xas: XArray operation state. + * @gfp: Memory allocation flags. + * + * Internal variant of xas_nomem(). + * + * Return: true if memory was needed, and was successfully allocated. + */ +static bool __xas_nomem(struct xa_state *xas, gfp_t gfp) + __must_hold(xas->xa->xa_lock) +{ + unsigned int lock_type = xa_lock_type(xas->xa); + + if (xas->xa_node != XA_ERROR(-ENOMEM)) { + xas_destroy(xas); + return false; + } + if (gfpflags_allow_blocking(gfp)) { + xas_unlock_type(xas, lock_type); + xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); + xas_lock_type(xas, lock_type); + } else { + xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); + } + if (!xas->xa_alloc) + return false; + XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); + xas->xa_node = XAS_RESTART; + return true; +} + +static void xas_update(struct xa_state *xas, struct xa_node *node) +{ + if (xas->xa_update) + xas->xa_update(node); + else + XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); +} + +static void *xas_alloc(struct xa_state *xas, unsigned int shift) +{ + struct xa_node *parent = xas->xa_node; + struct xa_node *node = xas->xa_alloc; + + if (xas_invalid(xas)) + return NULL; + + if (node) { + xas->xa_alloc = NULL; + } else { + node = kmem_cache_alloc(radix_tree_node_cachep, + GFP_NOWAIT | __GFP_NOWARN); + if (!node) { + xas_set_err(xas, -ENOMEM); + return NULL; + } + } + + if (parent) { + node->offset = xas->xa_offset; + parent->count++; + XA_NODE_BUG_ON(node, parent->count > XA_CHUNK_SIZE); + xas_update(xas, parent); + } + XA_NODE_BUG_ON(node, shift > BITS_PER_LONG); + XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); + node->shift = shift; + node->count = 0; + node->nr_values = 0; + RCU_INIT_POINTER(node->parent, xas->xa_node); + node->array = xas->xa; + + return node; +} + +/* + * Use this to calculate the maximum index that will need to be created + * in order to add the entry described by @xas. Because we cannot store a + * multiple-index entry at index 0, the calculation is a little more complex + * than you might expect. + */ +static unsigned long xas_max(struct xa_state *xas) +{ + unsigned long max = xas->xa_index; + +#ifdef CONFIG_XARRAY_MULTI + if (xas->xa_shift || xas->xa_sibs) { + unsigned long mask; + mask = (((xas->xa_sibs + 1UL) << xas->xa_shift) - 1); + max |= mask; + if (mask == max) + max++; + } +#endif + + return max; +} + +/* The maximum index that can be contained in the array without expanding it */ +static unsigned long max_index(void *entry) +{ + if (!xa_is_node(entry)) + return 0; + return (XA_CHUNK_SIZE << xa_to_node(entry)->shift) - 1; +} + +static void xas_shrink(struct xa_state *xas) +{ + struct xarray *xa = xas->xa; + struct xa_node *node = xas->xa_node; + + for (;;) { + void *entry; + + XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); + if (node->count != 1) + break; + entry = xa_entry_locked(xa, node, 0); + if (!entry) + break; + if (!xa_is_node(entry) && node->shift) + break; + xas->xa_node = XAS_BOUNDS; + + RCU_INIT_POINTER(xa->xa_head, entry); + + node->count = 0; + node->nr_values = 0; + if (!xa_is_node(entry)) + RCU_INIT_POINTER(node->slots[0], XA_RETRY_ENTRY); + xas_update(xas, node); + xa_node_free(node); + if (!xa_is_node(entry)) + break; + node = xa_to_node(entry); + node->parent = NULL; + } +} + +/* + * xas_delete_node() - Attempt to delete an xa_node + * @xas: Array operation state. + * + * Attempts to delete the @xas->xa_node. This will fail if xa->node has + * a non-zero reference count. + */ +static void xas_delete_node(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + for (;;) { + struct xa_node *parent; + + XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); + if (node->count) + break; + + parent = xa_parent_locked(xas->xa, node); + xas->xa_node = parent; + xas->xa_offset = node->offset; + xa_node_free(node); + + if (!parent) { + xas->xa->xa_head = NULL; + xas->xa_node = XAS_BOUNDS; + return; + } + + parent->slots[xas->xa_offset] = NULL; + parent->count--; + XA_NODE_BUG_ON(parent, parent->count > XA_CHUNK_SIZE); + node = parent; + xas_update(xas, node); + } + + if (!node->parent) + xas_shrink(xas); +} + +/** + * xas_free_nodes() - Free this node and all nodes that it references + * @xas: Array operation state. + * @top: Node to free + * + * This node has been removed from the tree. We must now free it and all + * of its subnodes. There may be RCU walkers with references into the tree, + * so we must replace all entries with retry markers. + */ +static void xas_free_nodes(struct xa_state *xas, struct xa_node *top) +{ + unsigned int offset = 0; + struct xa_node *node = top; + + for (;;) { + void *entry = xa_entry_locked(xas->xa, node, offset); + + if (xa_is_node(entry)) { + node = xa_to_node(entry); + offset = 0; + continue; + } + if (entry) + RCU_INIT_POINTER(node->slots[offset], XA_RETRY_ENTRY); + offset++; + while (offset == XA_CHUNK_SIZE) { + struct xa_node *parent; + + parent = xa_parent_locked(xas->xa, node); + offset = node->offset + 1; + node->count = 0; + node->nr_values = 0; + xas_update(xas, node); + xa_node_free(node); + if (node == top) + return; + node = parent; + } + } +} + +/* + * xas_expand adds nodes to the head of the tree until it has reached + * sufficient height to be able to contain @xas->xa_index + */ +static int xas_expand(struct xa_state *xas, void *head) +{ + struct xarray *xa = xas->xa; + struct xa_node *node = NULL; + unsigned int shift = 0; + unsigned long max = xas_max(xas); + + if (!head) { + if (max == 0) + return 0; + while ((max >> shift) >= XA_CHUNK_SIZE) + shift += XA_CHUNK_SHIFT; + return shift + XA_CHUNK_SHIFT; + } else if (xa_is_node(head)) { + node = xa_to_node(head); + shift = node->shift + XA_CHUNK_SHIFT; + } + xas->xa_node = NULL; + + while (max > max_index(head)) { + xa_mark_t mark = 0; + + XA_NODE_BUG_ON(node, shift > BITS_PER_LONG); + node = xas_alloc(xas, shift); + if (!node) + return -ENOMEM; + + node->count = 1; + if (xa_is_value(head)) + node->nr_values = 1; + RCU_INIT_POINTER(node->slots[0], head); + + /* Propagate the aggregated mark info to the new child */ + for (;;) { + if (xa_marked(xa, mark)) + node_set_mark(node, 0, mark); + if (mark == XA_MARK_MAX) + break; + mark_inc(mark); + } + + /* + * Now that the new node is fully initialised, we can add + * it to the tree + */ + if (xa_is_node(head)) { + xa_to_node(head)->offset = 0; + rcu_assign_pointer(xa_to_node(head)->parent, node); + } + head = xa_mk_node(node); + rcu_assign_pointer(xa->xa_head, head); + xas_update(xas, node); + + shift += XA_CHUNK_SHIFT; + } + + xas->xa_node = node; + return shift; +} + +/* + * xas_create() - Create a slot to store an entry in. + * @xas: XArray operation state. + * + * Most users will not need to call this function directly, as it is called + * by xas_store(). It is useful for doing conditional store operations + * (see the xa_cmpxchg() implementation for an example). + * + * Return: If the slot already existed, returns the contents of this slot. + * If the slot was newly created, returns NULL. If it failed to create the + * slot, returns NULL and indicates the error in @xas. + */ +static void *xas_create(struct xa_state *xas) +{ + struct xarray *xa = xas->xa; + void *entry; + void __rcu **slot; + struct xa_node *node = xas->xa_node; + int shift; + unsigned int order = xas->xa_shift; + + if (xas_top(node)) { + entry = xa_head_locked(xa); + xas->xa_node = NULL; + shift = xas_expand(xas, entry); + if (shift < 0) + return NULL; + entry = xa_head_locked(xa); + slot = &xa->xa_head; + } else if (xas_error(xas)) { + return NULL; + } else if (node) { + unsigned int offset = xas->xa_offset; + + shift = node->shift; + entry = xa_entry_locked(xa, node, offset); + slot = &node->slots[offset]; + } else { + shift = 0; + entry = xa_head_locked(xa); + slot = &xa->xa_head; + } + + while (shift > order) { + shift -= XA_CHUNK_SHIFT; + if (!entry) { + node = xas_alloc(xas, shift); + if (!node) + break; + rcu_assign_pointer(*slot, xa_mk_node(node)); + } else if (xa_is_node(entry)) { + node = xa_to_node(entry); + } else { + break; + } + entry = xas_descend(xas, node); + slot = &node->slots[xas->xa_offset]; + } + + return entry; +} + +static void update_node(struct xa_state *xas, struct xa_node *node, + int count, int values) +{ + if (!node || (!count && !values)) + return; + + node->count += count; + node->nr_values += values; + XA_NODE_BUG_ON(node, node->count > XA_CHUNK_SIZE); + XA_NODE_BUG_ON(node, node->nr_values > XA_CHUNK_SIZE); + xas_update(xas, node); + if (count < 0) + xas_delete_node(xas); +} + +/** + * xas_store() - Store this entry in the XArray. + * @xas: XArray operation state. + * @entry: New entry. + * + * If @xas is operating on a multi-index entry, the entry returned by this + * function is essentially meaningless (it may be an internal entry or it + * may be %NULL, even if there are non-NULL entries at some of the indices + * covered by the range). This is not a problem for any current users, + * and can be changed if needed. + * + * Return: The old entry at this index. + */ +void *xas_store(struct xa_state *xas, void *entry) +{ + struct xa_node *node; + void __rcu **slot = &xas->xa->xa_head; + unsigned int offset, max; + int count = 0; + int values = 0; + void *first, *next; + bool value = xa_is_value(entry); + + if (entry) + first = xas_create(xas); + else + first = xas_load(xas); + + if (xas_invalid(xas)) + return first; + node = xas->xa_node; + if (node && (xas->xa_shift < node->shift)) + xas->xa_sibs = 0; + if ((first == entry) && !xas->xa_sibs) + return first; + + next = first; + offset = xas->xa_offset; + max = xas->xa_offset + xas->xa_sibs; + if (node) { + slot = &node->slots[offset]; + if (xas->xa_sibs) + xas_squash_marks(xas); + } + if (!entry) + xas_init_marks(xas); + + for (;;) { + /* + * Must clear the marks before setting the entry to NULL, + * otherwise xas_for_each_marked may find a NULL entry and + * stop early. rcu_assign_pointer contains a release barrier + * so the mark clearing will appear to happen before the + * entry is set to NULL. + */ + rcu_assign_pointer(*slot, entry); + if (xa_is_node(next)) + xas_free_nodes(xas, xa_to_node(next)); + if (!node) + break; + count += !next - !entry; + values += !xa_is_value(first) - !value; + if (entry) { + if (offset == max) + break; + if (!xa_is_sibling(entry)) + entry = xa_mk_sibling(xas->xa_offset); + } else { + if (offset == XA_CHUNK_MASK) + break; + } + next = xa_entry_locked(xas->xa, node, ++offset); + if (!xa_is_sibling(next)) { + if (!entry && (offset > max)) + break; + first = next; + } + slot++; + } + + update_node(xas, node, count, values); + return first; +} +EXPORT_SYMBOL_GPL(xas_store); + /** * xas_get_mark() - Returns the state of this mark. * @xas: XArray operation state. @@ -240,6 +805,30 @@ void xas_clear_mark(const struct xa_state *xas, xa_mark_t mark) } EXPORT_SYMBOL_GPL(xas_clear_mark); +/** + * xas_init_marks() - Initialise all marks for the entry + * @xas: Array operations state. + * + * Initialise all marks for the entry specified by @xas. If we're tracking + * free entries with a mark, we need to set it on all entries. All other + * marks are cleared. + * + * This implementation is not as efficient as it could be; we may walk + * up the tree multiple times. + */ +void xas_init_marks(const struct xa_state *xas) +{ + xa_mark_t mark = 0; + + for (;;) { + xas_clear_mark(xas, mark); + if (mark == XA_MARK_MAX) + break; + mark_inc(mark); + } +} +EXPORT_SYMBOL_GPL(xas_init_marks); + /** * xa_init_flags() - Initialise an empty XArray with flags. * @xa: XArray. @@ -253,9 +842,19 @@ EXPORT_SYMBOL_GPL(xas_clear_mark); */ void xa_init_flags(struct xarray *xa, gfp_t flags) { + unsigned int lock_type; + static struct lock_class_key xa_lock_irq; + static struct lock_class_key xa_lock_bh; + spin_lock_init(&xa->xa_lock); xa->xa_flags = flags; xa->xa_head = NULL; + + lock_type = xa_lock_type(xa); + if (lock_type == XA_LOCK_IRQ) + lockdep_set_class(&xa->xa_lock, &xa_lock_irq); + else if (lock_type == XA_LOCK_BH) + lockdep_set_class(&xa->xa_lock, &xa_lock_bh); } EXPORT_SYMBOL(xa_init_flags); @@ -282,6 +881,100 @@ void *xa_load(struct xarray *xa, unsigned long index) } EXPORT_SYMBOL(xa_load); +static void *xas_result(struct xa_state *xas, void *curr) +{ + XA_NODE_BUG_ON(xas->xa_node, xa_is_internal(curr)); + if (xas_error(xas)) + curr = xas->xa_node; + return curr; +} + +/** + * __xa_erase() - Erase this entry from the XArray while locked. + * @xa: XArray. + * @index: Index into array. + * + * If the entry at this index is a multi-index entry then all indices will + * be erased, and the entry will no longer be a multi-index entry. + * This function expects the xa_lock to be held on entry. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if @gfp flags permit. + * Return: The old entry at this index. + */ +void *__xa_erase(struct xarray *xa, unsigned long index) +{ + XA_STATE(xas, xa, index); + return xas_result(&xas, xas_store(&xas, NULL)); +} +EXPORT_SYMBOL_GPL(__xa_erase); + +/** + * xa_store() - Store this entry in the XArray. + * @xa: XArray. + * @index: Index into array. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * After this function returns, loads from this index will return @entry. + * Storing into an existing multislot entry updates the entry of every index. + * The marks associated with @index are unaffected unless @entry is %NULL. + * + * Context: Process context. Takes and releases the xa_lock. May sleep + * if the @gfp flags permit. + * Return: The old entry at this index on success, xa_err(-EINVAL) if @entry + * cannot be stored in an XArray, or xa_err(-ENOMEM) if memory allocation + * failed. + */ +void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, index); + void *curr; + + if (WARN_ON_ONCE(xa_is_internal(entry))) + return XA_ERROR(-EINVAL); + + do { + xas_lock(&xas); + curr = xas_store(&xas, entry); + xas_unlock(&xas); + } while (xas_nomem(&xas, gfp)); + + return xas_result(&xas, curr); +} +EXPORT_SYMBOL(xa_store); + +/** + * __xa_store() - Store this entry in the XArray. + * @xa: XArray. + * @index: Index into array. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * You must already be holding the xa_lock when calling this function. + * It will drop the lock if needed to allocate memory, and then reacquire + * it afterwards. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if @gfp flags permit. + * Return: The old entry at this index or xa_err() if an error happened. + */ +void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, index); + void *curr; + + if (WARN_ON_ONCE(xa_is_internal(entry))) + return XA_ERROR(-EINVAL); + + do { + curr = xas_store(&xas, entry); + } while (__xas_nomem(&xas, gfp)); + + return xas_result(&xas, curr); +} +EXPORT_SYMBOL(__xa_store); + /** * __xa_set_mark() - Set this mark on this entry while locked. * @xa: XArray. diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h index e63662db131b..05dca5c203f3 100644 --- a/tools/include/linux/bitmap.h +++ b/tools/include/linux/bitmap.h @@ -15,6 +15,7 @@ void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, int bits); int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits); +void bitmap_clear(unsigned long *map, unsigned int start, int len); #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) diff --git a/tools/include/linux/spinlock.h b/tools/include/linux/spinlock.h index 622266b197d0..c934572d935c 100644 --- a/tools/include/linux/spinlock.h +++ b/tools/include/linux/spinlock.h @@ -37,4 +37,6 @@ static inline bool arch_spin_is_locked(arch_spinlock_t *mutex) return true; } +#include + #endif diff --git a/tools/testing/radix-tree/Makefile b/tools/testing/radix-tree/Makefile index 1379f1d78d0b..acf1afa01c5b 100644 --- a/tools/testing/radix-tree/Makefile +++ b/tools/testing/radix-tree/Makefile @@ -5,7 +5,7 @@ CFLAGS += -I. -I../../include -g -Og -Wall -D_LGPL_SOURCE -fsanitize=address \ LDFLAGS += -fsanitize=address -fsanitize=undefined LDLIBS+= -lpthread -lurcu TARGETS = main idr-test multiorder xarray -CORE_OFILES := xarray.o radix-tree.o idr.o linux.o test.o find_bit.o +CORE_OFILES := xarray.o radix-tree.o idr.o linux.o test.o find_bit.o bitmap.o OFILES = main.o $(CORE_OFILES) regression1.o regression2.o regression3.o \ tag_check.o multiorder.o idr-test.o iteration_check.o benchmark.o diff --git a/tools/testing/radix-tree/bitmap.c b/tools/testing/radix-tree/bitmap.c new file mode 100644 index 000000000000..66ec4a24a203 --- /dev/null +++ b/tools/testing/radix-tree/bitmap.c @@ -0,0 +1,23 @@ +/* lib/bitmap.c pulls in at least two other files. */ + +#include + +void bitmap_clear(unsigned long *map, unsigned int start, int len) +{ + unsigned long *p = map + BIT_WORD(start); + const unsigned int size = start + len; + int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); + + while (len - bits_to_clear >= 0) { + *p &= ~mask_to_clear; + len -= bits_to_clear; + bits_to_clear = BITS_PER_LONG; + mask_to_clear = ~0UL; + p++; + } + if (len) { + mask_to_clear &= BITMAP_LAST_WORD_MASK(size); + *p &= ~mask_to_clear; + } +} diff --git a/tools/testing/radix-tree/linux/kernel.h b/tools/testing/radix-tree/linux/kernel.h index 5d06ac75a14d..4568248222ae 100644 --- a/tools/testing/radix-tree/linux/kernel.h +++ b/tools/testing/radix-tree/linux/kernel.h @@ -18,4 +18,8 @@ #define pr_debug printk #define pr_cont printk +#define __acquires(x) +#define __releases(x) +#define __must_hold(x) + #endif /* _KERNEL_H */ diff --git a/tools/testing/radix-tree/linux/lockdep.h b/tools/testing/radix-tree/linux/lockdep.h new file mode 100644 index 000000000000..565fccdfe6e9 --- /dev/null +++ b/tools/testing/radix-tree/linux/lockdep.h @@ -0,0 +1,11 @@ +#ifndef _LINUX_LOCKDEP_H +#define _LINUX_LOCKDEP_H +struct lock_class_key { + unsigned int a; +}; + +static inline void lockdep_set_class(spinlock_t *lock, + struct lock_class_key *key) +{ +} +#endif /* _LINUX_LOCKDEP_H */ -- cgit v1.2.3 From 41aec91f55985e7f14ee75fe2f6e7bcfff0d0fae Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 10 Nov 2017 15:34:55 -0500 Subject: xarray: Add XArray conditional store operations Like cmpxchg(), xa_cmpxchg will only store to the index if the current entry matches the old entry. It returns the current entry, which is usually more useful than the errno returned by radix_tree_insert(). For the users who really only want the errno, the xa_insert() wrapper provides a more convenient calling convention. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 60 ++++++++++++++++++++++++++++++++++++++++++ lib/test_xarray.c | 20 ++++++++++++++ lib/xarray.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 151 insertions(+) (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 15eab63286ed..7f740f675b96 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -275,6 +275,8 @@ struct xarray { void xa_init_flags(struct xarray *, gfp_t flags); void *xa_load(struct xarray *, unsigned long index); void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); +void *xa_cmpxchg(struct xarray *, unsigned long index, + void *old, void *entry, gfp_t); bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); @@ -334,6 +336,34 @@ static inline void *xa_erase(struct xarray *xa, unsigned long index) return xa_store(xa, index, NULL, 0); } +/** + * xa_insert() - Store this entry in the XArray unless another entry is + * already present. + * @xa: XArray. + * @index: Index into array. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * If you would rather see the existing entry in the array, use xa_cmpxchg(). + * This function is for users who don't care what the entry is, only that + * one is present. + * + * Context: Process context. Takes and releases the xa_lock. + * May sleep if the @gfp flags permit. + * Return: 0 if the store succeeded. -EEXIST if another entry was present. + * -ENOMEM if memory could not be allocated. + */ +static inline int xa_insert(struct xarray *xa, unsigned long index, + void *entry, gfp_t gfp) +{ + void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp); + if (!curr) + return 0; + if (xa_is_err(curr)) + return xa_err(curr); + return -EEXIST; +} + #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) #define xa_lock(xa) spin_lock(&(xa)->xa_lock) #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) @@ -355,9 +385,39 @@ static inline void *xa_erase(struct xarray *xa, unsigned long index) */ void *__xa_erase(struct xarray *, unsigned long index); void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); +void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old, + void *entry, gfp_t); void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); +/** + * __xa_insert() - Store this entry in the XArray unless another entry is + * already present. + * @xa: XArray. + * @index: Index into array. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * If you would rather see the existing entry in the array, use __xa_cmpxchg(). + * This function is for users who don't care what the entry is, only that + * one is present. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if the @gfp flags permit. + * Return: 0 if the store succeeded. -EEXIST if another entry was present. + * -ENOMEM if memory could not be allocated. + */ +static inline int __xa_insert(struct xarray *xa, unsigned long index, + void *entry, gfp_t gfp) +{ + void *curr = __xa_cmpxchg(xa, index, NULL, entry, gfp); + if (!curr) + return 0; + if (xa_is_err(curr)) + return xa_err(curr); + return -EEXIST; +} + /** * xa_erase_bh() - Erase this entry from the XArray. * @xa: XArray. diff --git a/lib/test_xarray.c b/lib/test_xarray.c index b711030fbc32..fb472258b639 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -198,6 +198,25 @@ static noinline void check_xa_shrink(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_cmpxchg(struct xarray *xa) +{ + void *FIVE = xa_mk_value(5); + void *SIX = xa_mk_value(6); + void *LOTS = xa_mk_value(12345678); + + XA_BUG_ON(xa, !xa_empty(xa)); + XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_KERNEL) != NULL); + XA_BUG_ON(xa, xa_insert(xa, 12345678, xa, GFP_KERNEL) != -EEXIST); + XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, SIX, FIVE, GFP_KERNEL) != LOTS); + XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, LOTS, FIVE, GFP_KERNEL) != LOTS); + XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, FIVE, LOTS, GFP_KERNEL) != FIVE); + XA_BUG_ON(xa, xa_cmpxchg(xa, 5, FIVE, NULL, GFP_KERNEL) != NULL); + XA_BUG_ON(xa, xa_cmpxchg(xa, 5, NULL, FIVE, GFP_KERNEL) != NULL); + xa_erase_index(xa, 12345678); + xa_erase_index(xa, 5); + XA_BUG_ON(xa, !xa_empty(xa)); +} + static noinline void check_multi_store(struct xarray *xa) { #ifdef CONFIG_XARRAY_MULTI @@ -274,6 +293,7 @@ static int xarray_checks(void) check_xa_load(&array); check_xa_mark(&array); check_xa_shrink(&array); + check_cmpxchg(&array); check_multi_store(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); diff --git a/lib/xarray.c b/lib/xarray.c index 4596a95ed9cd..2ba5a98ec618 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -975,6 +975,77 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) } EXPORT_SYMBOL(__xa_store); +/** + * xa_cmpxchg() - Conditionally replace an entry in the XArray. + * @xa: XArray. + * @index: Index into array. + * @old: Old value to test against. + * @entry: New value to place in array. + * @gfp: Memory allocation flags. + * + * If the entry at @index is the same as @old, replace it with @entry. + * If the return value is equal to @old, then the exchange was successful. + * + * Context: Process context. Takes and releases the xa_lock. May sleep + * if the @gfp flags permit. + * Return: The old value at this index or xa_err() if an error happened. + */ +void *xa_cmpxchg(struct xarray *xa, unsigned long index, + void *old, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, index); + void *curr; + + if (WARN_ON_ONCE(xa_is_internal(entry))) + return XA_ERROR(-EINVAL); + + do { + xas_lock(&xas); + curr = xas_load(&xas); + if (curr == old) + xas_store(&xas, entry); + xas_unlock(&xas); + } while (xas_nomem(&xas, gfp)); + + return xas_result(&xas, curr); +} +EXPORT_SYMBOL(xa_cmpxchg); + +/** + * __xa_cmpxchg() - Store this entry in the XArray. + * @xa: XArray. + * @index: Index into array. + * @old: Old value to test against. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * You must already be holding the xa_lock when calling this function. + * It will drop the lock if needed to allocate memory, and then reacquire + * it afterwards. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if @gfp flags permit. + * Return: The old entry at this index or xa_err() if an error happened. + */ +void *__xa_cmpxchg(struct xarray *xa, unsigned long index, + void *old, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, index); + void *curr; + + if (WARN_ON_ONCE(xa_is_internal(entry))) + return XA_ERROR(-EINVAL); + + do { + curr = xas_load(&xas); + if (curr == old) + xas_store(&xas, entry); + } while (__xas_nomem(&xas, gfp)); + + return xas_result(&xas, curr); +} +EXPORT_SYMBOL(__xa_cmpxchg); + /** * __xa_set_mark() - Set this mark on this entry while locked. * @xa: XArray. -- cgit v1.2.3 From b803b42823d0d9e8b6deccf01ffc2aba5d0738df Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 14 Nov 2017 08:30:11 -0500 Subject: xarray: Add XArray iterators The xa_for_each iterator allows the user to efficiently walk a range of the array, executing the loop body once for each entry in that range that matches the filter. This commit also includes xa_find() and xa_find_after() which are helper functions for xa_for_each() but may also be useful in their own right. In the xas family of functions, we have xas_for_each(), xas_find(), xas_next_entry(), xas_for_each_tagged(), xas_find_tagged(), xas_next_tagged() and xas_pause(). Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 165 ++++++++++++++++++++++++++++ lib/test_xarray.c | 183 +++++++++++++++++++++++++++++++ lib/xarray.c | 292 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 640 insertions(+) (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 7f740f675b96..66b10efa5a50 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -280,6 +280,10 @@ void *xa_cmpxchg(struct xarray *, unsigned long index, bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); +void *xa_find(struct xarray *xa, unsigned long *index, + unsigned long max, xa_mark_t) __attribute__((nonnull(2))); +void *xa_find_after(struct xarray *xa, unsigned long *index, + unsigned long max, xa_mark_t) __attribute__((nonnull(2))); /** * xa_init() - Initialise an empty XArray. @@ -364,6 +368,35 @@ static inline int xa_insert(struct xarray *xa, unsigned long index, return -EEXIST; } +/** + * xa_for_each() - Iterate over a portion of an XArray. + * @xa: XArray. + * @entry: Entry retrieved from array. + * @index: Index of @entry. + * @max: Maximum index to retrieve from array. + * @filter: Selection criterion. + * + * Initialise @index to the lowest index you want to retrieve from the + * array. During the iteration, @entry will have the value of the entry + * stored in @xa at @index. The iteration will skip all entries in the + * array which do not match @filter. You may modify @index during the + * iteration if you want to skip or reprocess indices. It is safe to modify + * the array during the iteration. At the end of the iteration, @entry will + * be set to NULL and @index will have a value less than or equal to max. + * + * xa_for_each() is O(n.log(n)) while xas_for_each() is O(n). You have + * to handle your own locking with xas_for_each(), and if you have to unlock + * after each iteration, it will also end up being O(n.log(n)). xa_for_each() + * will spin if it hits a retry entry; if you intend to see retry entries, + * you should use the xas_for_each() iterator instead. The xas_for_each() + * iterator will expand into more inline code than xa_for_each(). + * + * Context: Any context. Takes and releases the RCU lock. + */ +#define xa_for_each(xa, entry, index, max, filter) \ + for (entry = xa_find(xa, &index, max, filter); entry; \ + entry = xa_find_after(xa, &index, max, filter)) + #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) #define xa_lock(xa) spin_lock(&(xa)->xa_lock) #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) @@ -835,13 +868,16 @@ static inline bool xas_retry(struct xa_state *xas, const void *entry) void *xas_load(struct xa_state *); void *xas_store(struct xa_state *, void *entry); +void *xas_find(struct xa_state *, unsigned long max); bool xas_get_mark(const struct xa_state *, xa_mark_t); void xas_set_mark(const struct xa_state *, xa_mark_t); void xas_clear_mark(const struct xa_state *, xa_mark_t); +void *xas_find_marked(struct xa_state *, unsigned long max, xa_mark_t); void xas_init_marks(const struct xa_state *); bool xas_nomem(struct xa_state *, gfp_t); +void xas_pause(struct xa_state *); /** * xas_reload() - Refetch an entry from the xarray. @@ -914,4 +950,133 @@ static inline void xas_set_update(struct xa_state *xas, xa_update_node_t update) xas->xa_update = update; } +/** + * xas_next_entry() - Advance iterator to next present entry. + * @xas: XArray operation state. + * @max: Highest index to return. + * + * xas_next_entry() is an inline function to optimise xarray traversal for + * speed. It is equivalent to calling xas_find(), and will call xas_find() + * for all the hard cases. + * + * Return: The next present entry after the one currently referred to by @xas. + */ +static inline void *xas_next_entry(struct xa_state *xas, unsigned long max) +{ + struct xa_node *node = xas->xa_node; + void *entry; + + if (unlikely(xas_not_node(node) || node->shift || + xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK))) + return xas_find(xas, max); + + do { + if (unlikely(xas->xa_index >= max)) + return xas_find(xas, max); + if (unlikely(xas->xa_offset == XA_CHUNK_MASK)) + return xas_find(xas, max); + entry = xa_entry(xas->xa, node, xas->xa_offset + 1); + if (unlikely(xa_is_internal(entry))) + return xas_find(xas, max); + xas->xa_offset++; + xas->xa_index++; + } while (!entry); + + return entry; +} + +/* Private */ +static inline unsigned int xas_find_chunk(struct xa_state *xas, bool advance, + xa_mark_t mark) +{ + unsigned long *addr = xas->xa_node->marks[(__force unsigned)mark]; + unsigned int offset = xas->xa_offset; + + if (advance) + offset++; + if (XA_CHUNK_SIZE == BITS_PER_LONG) { + if (offset < XA_CHUNK_SIZE) { + unsigned long data = *addr & (~0UL << offset); + if (data) + return __ffs(data); + } + return XA_CHUNK_SIZE; + } + + return find_next_bit(addr, XA_CHUNK_SIZE, offset); +} + +/** + * xas_next_marked() - Advance iterator to next marked entry. + * @xas: XArray operation state. + * @max: Highest index to return. + * @mark: Mark to search for. + * + * xas_next_marked() is an inline function to optimise xarray traversal for + * speed. It is equivalent to calling xas_find_marked(), and will call + * xas_find_marked() for all the hard cases. + * + * Return: The next marked entry after the one currently referred to by @xas. + */ +static inline void *xas_next_marked(struct xa_state *xas, unsigned long max, + xa_mark_t mark) +{ + struct xa_node *node = xas->xa_node; + unsigned int offset; + + if (unlikely(xas_not_node(node) || node->shift)) + return xas_find_marked(xas, max, mark); + offset = xas_find_chunk(xas, true, mark); + xas->xa_offset = offset; + xas->xa_index = (xas->xa_index & ~XA_CHUNK_MASK) + offset; + if (xas->xa_index > max) + return NULL; + if (offset == XA_CHUNK_SIZE) + return xas_find_marked(xas, max, mark); + return xa_entry(xas->xa, node, offset); +} + +/* + * If iterating while holding a lock, drop the lock and reschedule + * every %XA_CHECK_SCHED loops. + */ +enum { + XA_CHECK_SCHED = 4096, +}; + +/** + * xas_for_each() - Iterate over a range of an XArray. + * @xas: XArray operation state. + * @entry: Entry retrieved from the array. + * @max: Maximum index to retrieve from array. + * + * The loop body will be executed for each entry present in the xarray + * between the current xas position and @max. @entry will be set to + * the entry retrieved from the xarray. It is safe to delete entries + * from the array in the loop body. You should hold either the RCU lock + * or the xa_lock while iterating. If you need to drop the lock, call + * xas_pause() first. + */ +#define xas_for_each(xas, entry, max) \ + for (entry = xas_find(xas, max); entry; \ + entry = xas_next_entry(xas, max)) + +/** + * xas_for_each_marked() - Iterate over a range of an XArray. + * @xas: XArray operation state. + * @entry: Entry retrieved from the array. + * @max: Maximum index to retrieve from array. + * @mark: Mark to search for. + * + * The loop body will be executed for each marked entry in the xarray + * between the current xas position and @max. @entry will be set to + * the entry retrieved from the xarray. It is safe to delete entries + * from the array in the loop body. You should hold either the RCU lock + * or the xa_lock while iterating. If you need to drop the lock, call + * xas_pause() first. + */ +#define xas_for_each_marked(xas, entry, max, mark) \ + for (entry = xas_find_marked(xas, max, mark); entry; \ + entry = xas_next_marked(xas, max, mark)) + #endif /* _LINUX_XARRAY_H */ diff --git a/lib/test_xarray.c b/lib/test_xarray.c index fb472258b639..e3c2d4d00b15 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -75,6 +75,48 @@ static noinline void check_xa_err(struct xarray *xa) // XA_BUG_ON(xa, xa_err(xa_store(xa, 0, xa_mk_internal(0), 0)) != -EINVAL); } +static noinline void check_xas_retry(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + void *entry; + + xa_store_index(xa, 0, GFP_KERNEL); + xa_store_index(xa, 1, GFP_KERNEL); + + rcu_read_lock(); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_value(0)); + xa_erase_index(xa, 1); + XA_BUG_ON(xa, !xa_is_retry(xas_reload(&xas))); + XA_BUG_ON(xa, xas_retry(&xas, NULL)); + XA_BUG_ON(xa, xas_retry(&xas, xa_mk_value(0))); + xas_reset(&xas); + XA_BUG_ON(xa, xas.xa_node != XAS_RESTART); + XA_BUG_ON(xa, xas_next_entry(&xas, ULONG_MAX) != xa_mk_value(0)); + XA_BUG_ON(xa, xas.xa_node != NULL); + + XA_BUG_ON(xa, xa_store_index(xa, 1, GFP_KERNEL) != NULL); + XA_BUG_ON(xa, !xa_is_internal(xas_reload(&xas))); + xas.xa_node = XAS_RESTART; + XA_BUG_ON(xa, xas_next_entry(&xas, ULONG_MAX) != xa_mk_value(0)); + rcu_read_unlock(); + + /* Make sure we can iterate through retry entries */ + xas_lock(&xas); + xas_set(&xas, 0); + xas_store(&xas, XA_RETRY_ENTRY); + xas_set(&xas, 1); + xas_store(&xas, XA_RETRY_ENTRY); + + xas_set(&xas, 0); + xas_for_each(&xas, entry, ULONG_MAX) { + xas_store(&xas, xa_mk_value(xas.xa_index)); + } + xas_unlock(&xas); + + xa_erase_index(xa, 0); + xa_erase_index(xa, 1); +} + static noinline void check_xa_load(struct xarray *xa) { unsigned long i, j; @@ -217,6 +259,44 @@ static noinline void check_cmpxchg(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_xas_erase(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + void *entry; + unsigned long i, j; + + for (i = 0; i < 200; i++) { + for (j = i; j < 2 * i + 17; j++) { + xas_set(&xas, j); + do { + xas_lock(&xas); + xas_store(&xas, xa_mk_value(j)); + xas_unlock(&xas); + } while (xas_nomem(&xas, GFP_KERNEL)); + } + + xas_set(&xas, ULONG_MAX); + do { + xas_lock(&xas); + xas_store(&xas, xa_mk_value(0)); + xas_unlock(&xas); + } while (xas_nomem(&xas, GFP_KERNEL)); + + xas_lock(&xas); + xas_store(&xas, NULL); + + xas_set(&xas, 0); + j = i; + xas_for_each(&xas, entry, ULONG_MAX) { + XA_BUG_ON(xa, entry != xa_mk_value(j)); + xas_store(&xas, NULL); + j++; + } + xas_unlock(&xas); + XA_BUG_ON(xa, !xa_empty(xa)); + } +} + static noinline void check_multi_store(struct xarray *xa) { #ifdef CONFIG_XARRAY_MULTI @@ -285,16 +365,119 @@ static noinline void check_multi_store(struct xarray *xa) #endif } +static noinline void check_multi_find(struct xarray *xa) +{ +#ifdef CONFIG_XARRAY_MULTI + unsigned long index; + + xa_store_order(xa, 12, 2, xa_mk_value(12), GFP_KERNEL); + XA_BUG_ON(xa, xa_store_index(xa, 16, GFP_KERNEL) != NULL); + + index = 0; + XA_BUG_ON(xa, xa_find(xa, &index, ULONG_MAX, XA_PRESENT) != + xa_mk_value(12)); + XA_BUG_ON(xa, index != 12); + index = 13; + XA_BUG_ON(xa, xa_find(xa, &index, ULONG_MAX, XA_PRESENT) != + xa_mk_value(12)); + XA_BUG_ON(xa, (index < 12) || (index >= 16)); + XA_BUG_ON(xa, xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT) != + xa_mk_value(16)); + XA_BUG_ON(xa, index != 16); + + xa_erase_index(xa, 12); + xa_erase_index(xa, 16); + XA_BUG_ON(xa, !xa_empty(xa)); +#endif +} + +static noinline void check_multi_find_2(struct xarray *xa) +{ + unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 10 : 1; + unsigned int i, j; + void *entry; + + for (i = 0; i < max_order; i++) { + unsigned long index = 1UL << i; + for (j = 0; j < index; j++) { + XA_STATE(xas, xa, j + index); + xa_store_index(xa, index - 1, GFP_KERNEL); + xa_store_order(xa, index, i, xa_mk_value(index), + GFP_KERNEL); + rcu_read_lock(); + xas_for_each(&xas, entry, ULONG_MAX) { + xa_erase_index(xa, index); + } + rcu_read_unlock(); + xa_erase_index(xa, index - 1); + XA_BUG_ON(xa, !xa_empty(xa)); + } + } +} + +static noinline void check_find(struct xarray *xa) +{ + unsigned long i, j, k; + + XA_BUG_ON(xa, !xa_empty(xa)); + + /* + * Check xa_find with all pairs between 0 and 99 inclusive, + * starting at every index between 0 and 99 + */ + for (i = 0; i < 100; i++) { + XA_BUG_ON(xa, xa_store_index(xa, i, GFP_KERNEL) != NULL); + xa_set_mark(xa, i, XA_MARK_0); + for (j = 0; j < i; j++) { + XA_BUG_ON(xa, xa_store_index(xa, j, GFP_KERNEL) != + NULL); + xa_set_mark(xa, j, XA_MARK_0); + for (k = 0; k < 100; k++) { + unsigned long index = k; + void *entry = xa_find(xa, &index, ULONG_MAX, + XA_PRESENT); + if (k <= j) + XA_BUG_ON(xa, index != j); + else if (k <= i) + XA_BUG_ON(xa, index != i); + else + XA_BUG_ON(xa, entry != NULL); + + index = k; + entry = xa_find(xa, &index, ULONG_MAX, + XA_MARK_0); + if (k <= j) + XA_BUG_ON(xa, index != j); + else if (k <= i) + XA_BUG_ON(xa, index != i); + else + XA_BUG_ON(xa, entry != NULL); + } + xa_erase_index(xa, j); + XA_BUG_ON(xa, xa_get_mark(xa, j, XA_MARK_0)); + XA_BUG_ON(xa, !xa_get_mark(xa, i, XA_MARK_0)); + } + xa_erase_index(xa, i); + XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_0)); + } + XA_BUG_ON(xa, !xa_empty(xa)); + check_multi_find(xa); + check_multi_find_2(xa); +} + static DEFINE_XARRAY(array); static int xarray_checks(void) { check_xa_err(&array); + check_xas_retry(&array); check_xa_load(&array); check_xa_mark(&array); check_xa_shrink(&array); + check_xas_erase(&array); check_cmpxchg(&array); check_multi_store(&array); + check_find(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run == tests_passed) ? 0 : -EINVAL; diff --git a/lib/xarray.c b/lib/xarray.c index 2ba5a98ec618..24494f42daa6 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -128,6 +128,11 @@ static unsigned int get_offset(unsigned long index, struct xa_node *node) return (index >> node->shift) & XA_CHUNK_MASK; } +static void xas_set_offset(struct xa_state *xas) +{ + xas->xa_offset = get_offset(xas->xa_index, xas->xa_node); +} + /* move the index either forwards (find) or backwards (sibling slot) */ static void xas_move_index(struct xa_state *xas, unsigned long offset) { @@ -136,6 +141,12 @@ static void xas_move_index(struct xa_state *xas, unsigned long offset) xas->xa_index += offset << shift; } +static void xas_advance(struct xa_state *xas) +{ + xas->xa_offset++; + xas_move_index(xas, xas->xa_offset); +} + static void *set_bounds(struct xa_state *xas) { xas->xa_node = XAS_BOUNDS; @@ -829,6 +840,202 @@ void xas_init_marks(const struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_init_marks); +/** + * xas_pause() - Pause a walk to drop a lock. + * @xas: XArray operation state. + * + * Some users need to pause a walk and drop the lock they're holding in + * order to yield to a higher priority thread or carry out an operation + * on an entry. Those users should call this function before they drop + * the lock. It resets the @xas to be suitable for the next iteration + * of the loop after the user has reacquired the lock. If most entries + * found during a walk require you to call xas_pause(), the xa_for_each() + * iterator may be more appropriate. + * + * Note that xas_pause() only works for forward iteration. If a user needs + * to pause a reverse iteration, we will need a xas_pause_rev(). + */ +void xas_pause(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (xas_invalid(xas)) + return; + + if (node) { + unsigned int offset = xas->xa_offset; + while (++offset < XA_CHUNK_SIZE) { + if (!xa_is_sibling(xa_entry(xas->xa, node, offset))) + break; + } + xas->xa_index += (offset - xas->xa_offset) << node->shift; + } else { + xas->xa_index++; + } + xas->xa_node = XAS_RESTART; +} +EXPORT_SYMBOL_GPL(xas_pause); + +/** + * xas_find() - Find the next present entry in the XArray. + * @xas: XArray operation state. + * @max: Highest index to return. + * + * If the @xas has not yet been walked to an entry, return the entry + * which has an index >= xas.xa_index. If it has been walked, the entry + * currently being pointed at has been processed, and so we move to the + * next entry. + * + * If no entry is found and the array is smaller than @max, the iterator + * is set to the smallest index not yet in the array. This allows @xas + * to be immediately passed to xas_store(). + * + * Return: The entry, if found, otherwise %NULL. + */ +void *xas_find(struct xa_state *xas, unsigned long max) +{ + void *entry; + + if (xas_error(xas)) + return NULL; + + if (!xas->xa_node) { + xas->xa_index = 1; + return set_bounds(xas); + } else if (xas_top(xas->xa_node)) { + entry = xas_load(xas); + if (entry || xas_not_node(xas->xa_node)) + return entry; + } else if (!xas->xa_node->shift && + xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK)) { + xas->xa_offset = ((xas->xa_index - 1) & XA_CHUNK_MASK) + 1; + } + + xas_advance(xas); + + while (xas->xa_node && (xas->xa_index <= max)) { + if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) { + xas->xa_offset = xas->xa_node->offset + 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + continue; + } + + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (xa_is_node(entry)) { + xas->xa_node = xa_to_node(entry); + xas->xa_offset = 0; + continue; + } + if (entry && !xa_is_sibling(entry)) + return entry; + + xas_advance(xas); + } + + if (!xas->xa_node) + xas->xa_node = XAS_BOUNDS; + return NULL; +} +EXPORT_SYMBOL_GPL(xas_find); + +/** + * xas_find_marked() - Find the next marked entry in the XArray. + * @xas: XArray operation state. + * @max: Highest index to return. + * @mark: Mark number to search for. + * + * If the @xas has not yet been walked to an entry, return the marked entry + * which has an index >= xas.xa_index. If it has been walked, the entry + * currently being pointed at has been processed, and so we return the + * first marked entry with an index > xas.xa_index. + * + * If no marked entry is found and the array is smaller than @max, @xas is + * set to the bounds state and xas->xa_index is set to the smallest index + * not yet in the array. This allows @xas to be immediately passed to + * xas_store(). + * + * If no entry is found before @max is reached, @xas is set to the restart + * state. + * + * Return: The entry, if found, otherwise %NULL. + */ +void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark) +{ + bool advance = true; + unsigned int offset; + void *entry; + + if (xas_error(xas)) + return NULL; + + if (!xas->xa_node) { + xas->xa_index = 1; + goto out; + } else if (xas_top(xas->xa_node)) { + advance = false; + entry = xa_head(xas->xa); + xas->xa_node = NULL; + if (xas->xa_index > max_index(entry)) + goto bounds; + if (!xa_is_node(entry)) { + if (xa_marked(xas->xa, mark)) + return entry; + xas->xa_index = 1; + goto out; + } + xas->xa_node = xa_to_node(entry); + xas->xa_offset = xas->xa_index >> xas->xa_node->shift; + } + + while (xas->xa_index <= max) { + if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) { + xas->xa_offset = xas->xa_node->offset + 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + break; + advance = false; + continue; + } + + if (!advance) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (xa_is_sibling(entry)) { + xas->xa_offset = xa_to_sibling(entry); + xas_move_index(xas, xas->xa_offset); + } + } + + offset = xas_find_chunk(xas, advance, mark); + if (offset > xas->xa_offset) { + advance = false; + xas_move_index(xas, offset); + /* Mind the wrap */ + if ((xas->xa_index - 1) >= max) + goto max; + xas->xa_offset = offset; + if (offset == XA_CHUNK_SIZE) + continue; + } + + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + xas->xa_node = xa_to_node(entry); + xas_set_offset(xas); + } + +out: + if (!max) + goto max; +bounds: + xas->xa_node = XAS_BOUNDS; + return NULL; +max: + xas->xa_node = XAS_RESTART; + return NULL; +} +EXPORT_SYMBOL_GPL(xas_find_marked); + /** * xa_init_flags() - Initialise an empty XArray with flags. * @xa: XArray. @@ -1152,6 +1359,91 @@ void xa_clear_mark(struct xarray *xa, unsigned long index, xa_mark_t mark) } EXPORT_SYMBOL(xa_clear_mark); +/** + * xa_find() - Search the XArray for an entry. + * @xa: XArray. + * @indexp: Pointer to an index. + * @max: Maximum index to search to. + * @filter: Selection criterion. + * + * Finds the entry in @xa which matches the @filter, and has the lowest + * index that is at least @indexp and no more than @max. + * If an entry is found, @indexp is updated to be the index of the entry. + * This function is protected by the RCU read lock, so it may not find + * entries which are being simultaneously added. It will not return an + * %XA_RETRY_ENTRY; if you need to see retry entries, use xas_find(). + * + * Context: Any context. Takes and releases the RCU lock. + * Return: The entry, if found, otherwise %NULL. + */ +void *xa_find(struct xarray *xa, unsigned long *indexp, + unsigned long max, xa_mark_t filter) +{ + XA_STATE(xas, xa, *indexp); + void *entry; + + rcu_read_lock(); + do { + if ((__force unsigned int)filter < XA_MAX_MARKS) + entry = xas_find_marked(&xas, max, filter); + else + entry = xas_find(&xas, max); + } while (xas_retry(&xas, entry)); + rcu_read_unlock(); + + if (entry) + *indexp = xas.xa_index; + return entry; +} +EXPORT_SYMBOL(xa_find); + +/** + * xa_find_after() - Search the XArray for a present entry. + * @xa: XArray. + * @indexp: Pointer to an index. + * @max: Maximum index to search to. + * @filter: Selection criterion. + * + * Finds the entry in @xa which matches the @filter and has the lowest + * index that is above @indexp and no more than @max. + * If an entry is found, @indexp is updated to be the index of the entry. + * This function is protected by the RCU read lock, so it may miss entries + * which are being simultaneously added. It will not return an + * %XA_RETRY_ENTRY; if you need to see retry entries, use xas_find(). + * + * Context: Any context. Takes and releases the RCU lock. + * Return: The pointer, if found, otherwise %NULL. + */ +void *xa_find_after(struct xarray *xa, unsigned long *indexp, + unsigned long max, xa_mark_t filter) +{ + XA_STATE(xas, xa, *indexp + 1); + void *entry; + + rcu_read_lock(); + for (;;) { + if ((__force unsigned int)filter < XA_MAX_MARKS) + entry = xas_find_marked(&xas, max, filter); + else + entry = xas_find(&xas, max); + if (xas.xa_shift) { + if (xas.xa_index & ((1UL << xas.xa_shift) - 1)) + continue; + } else { + if (xas.xa_offset < (xas.xa_index & XA_CHUNK_MASK)) + continue; + } + if (!xas_retry(&xas, entry)) + break; + } + rcu_read_unlock(); + + if (entry) + *indexp = xas.xa_index; + return entry; +} +EXPORT_SYMBOL(xa_find_after); + #ifdef XA_DEBUG void xa_dump_node(const struct xa_node *node) { -- cgit v1.2.3 From 80a0a1a9a3cde9b23851e8eb7160e2786549306a Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 14 Nov 2017 16:42:22 -0500 Subject: xarray: Extract entries from an XArray The xa_extract function combines the functionality of radix_tree_gang_lookup() and radix_tree_gang_lookup_tagged(). It extracts entries matching the specified filter into a normal array. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 2 ++ lib/xarray.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 82 insertions(+) (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 66b10efa5a50..82ceed981924 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -284,6 +284,8 @@ void *xa_find(struct xarray *xa, unsigned long *index, unsigned long max, xa_mark_t) __attribute__((nonnull(2))); void *xa_find_after(struct xarray *xa, unsigned long *index, unsigned long max, xa_mark_t) __attribute__((nonnull(2))); +unsigned int xa_extract(struct xarray *, void **dst, unsigned long start, + unsigned long max, unsigned int n, xa_mark_t); /** * xa_init() - Initialise an empty XArray. diff --git a/lib/xarray.c b/lib/xarray.c index 24494f42daa6..70e04810c8c2 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1444,6 +1444,86 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp, } EXPORT_SYMBOL(xa_find_after); +static unsigned int xas_extract_present(struct xa_state *xas, void **dst, + unsigned long max, unsigned int n) +{ + void *entry; + unsigned int i = 0; + + rcu_read_lock(); + xas_for_each(xas, entry, max) { + if (xas_retry(xas, entry)) + continue; + dst[i++] = entry; + if (i == n) + break; + } + rcu_read_unlock(); + + return i; +} + +static unsigned int xas_extract_marked(struct xa_state *xas, void **dst, + unsigned long max, unsigned int n, xa_mark_t mark) +{ + void *entry; + unsigned int i = 0; + + rcu_read_lock(); + xas_for_each_marked(xas, entry, max, mark) { + if (xas_retry(xas, entry)) + continue; + dst[i++] = entry; + if (i == n) + break; + } + rcu_read_unlock(); + + return i; +} + +/** + * xa_extract() - Copy selected entries from the XArray into a normal array. + * @xa: The source XArray to copy from. + * @dst: The buffer to copy entries into. + * @start: The first index in the XArray eligible to be selected. + * @max: The last index in the XArray eligible to be selected. + * @n: The maximum number of entries to copy. + * @filter: Selection criterion. + * + * Copies up to @n entries that match @filter from the XArray. The + * copied entries will have indices between @start and @max, inclusive. + * + * The @filter may be an XArray mark value, in which case entries which are + * marked with that mark will be copied. It may also be %XA_PRESENT, in + * which case all entries which are not NULL will be copied. + * + * The entries returned may not represent a snapshot of the XArray at a + * moment in time. For example, if another thread stores to index 5, then + * index 10, calling xa_extract() may return the old contents of index 5 + * and the new contents of index 10. Indices not modified while this + * function is running will not be skipped. + * + * If you need stronger guarantees, holding the xa_lock across calls to this + * function will prevent concurrent modification. + * + * Context: Any context. Takes and releases the RCU lock. + * Return: The number of entries copied. + */ +unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, + unsigned long max, unsigned int n, xa_mark_t filter) +{ + XA_STATE(xas, xa, start); + + if (!n) + return 0; + + if ((__force unsigned int)filter < XA_MAX_MARKS) + return xas_extract_marked(&xas, dst, max, n, filter); + return xas_extract_present(&xas, dst, max, n); +} +EXPORT_SYMBOL(xa_extract); + #ifdef XA_DEBUG void xa_dump_node(const struct xa_node *node) { -- cgit v1.2.3 From 687149fca1f37c447e5d161e0a4a04cb2c880cb6 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 17 Nov 2017 08:16:34 -0500 Subject: xarray: Destroy an XArray This function frees all the internal memory allocated to the xarray and reinitialises it to be empty. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 1 + lib/test_xarray.c | 34 ++++++++++++++++++++++++++++++++++ lib/xarray.c | 28 ++++++++++++++++++++++++++++ 3 files changed, 63 insertions(+) (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 82ceed981924..0a758fa3ed2c 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -286,6 +286,7 @@ void *xa_find_after(struct xarray *xa, unsigned long *index, unsigned long max, xa_mark_t) __attribute__((nonnull(2))); unsigned int xa_extract(struct xarray *, void **dst, unsigned long start, unsigned long max, unsigned int n, xa_mark_t); +void xa_destroy(struct xarray *); /** * xa_init() - Initialise an empty XArray. diff --git a/lib/test_xarray.c b/lib/test_xarray.c index e3c2d4d00b15..a96f67caa1c2 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -465,6 +465,39 @@ static noinline void check_find(struct xarray *xa) check_multi_find_2(xa); } +static noinline void check_destroy(struct xarray *xa) +{ + unsigned long index; + + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Destroying an empty array is a no-op */ + xa_destroy(xa); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Destroying an array with a single entry */ + for (index = 0; index < 1000; index++) { + xa_store_index(xa, index, GFP_KERNEL); + XA_BUG_ON(xa, xa_empty(xa)); + xa_destroy(xa); + XA_BUG_ON(xa, !xa_empty(xa)); + } + + /* Destroying an array with a single entry at ULONG_MAX */ + xa_store(xa, ULONG_MAX, xa, GFP_KERNEL); + XA_BUG_ON(xa, xa_empty(xa)); + xa_destroy(xa); + XA_BUG_ON(xa, !xa_empty(xa)); + +#ifdef CONFIG_XARRAY_MULTI + /* Destroying an array with a multi-index entry */ + xa_store_order(xa, 1 << 11, 11, xa, GFP_KERNEL); + XA_BUG_ON(xa, xa_empty(xa)); + xa_destroy(xa); + XA_BUG_ON(xa, !xa_empty(xa)); +#endif +} + static DEFINE_XARRAY(array); static int xarray_checks(void) @@ -478,6 +511,7 @@ static int xarray_checks(void) check_cmpxchg(&array); check_multi_store(&array); check_find(&array); + check_destroy(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run == tests_passed) ? 0 : -EINVAL; diff --git a/lib/xarray.c b/lib/xarray.c index 70e04810c8c2..057dbe0d3bf6 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1524,6 +1524,34 @@ unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, } EXPORT_SYMBOL(xa_extract); +/** + * xa_destroy() - Free all internal data structures. + * @xa: XArray. + * + * After calling this function, the XArray is empty and has freed all memory + * allocated for its internal data structures. You are responsible for + * freeing the objects referenced by the XArray. + * + * Context: Any context. Takes and releases the xa_lock, interrupt-safe. + */ +void xa_destroy(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + unsigned long flags; + void *entry; + + xas.xa_node = NULL; + xas_lock_irqsave(&xas, flags); + entry = xa_head_locked(xa); + RCU_INIT_POINTER(xa->xa_head, NULL); + xas_init_marks(&xas); + /* lockdep checks we're still holding the lock in xas_free_nodes() */ + if (xa_is_node(entry)) + xas_free_nodes(&xas, xa_to_node(entry)); + xas_unlock_irqrestore(&xas, flags); +} +EXPORT_SYMBOL(xa_destroy); + #ifdef XA_DEBUG void xa_dump_node(const struct xa_node *node) { -- cgit v1.2.3 From 64d3e9a9e0cc51957d243dd2b0adc5d74ff5e128 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 1 Dec 2017 00:06:52 -0500 Subject: xarray: Step through an XArray The xas_next and xas_prev functions move the xas index by one position, and adjust the rest of the iterator state to match it. This is more efficient than calling xas_set() as it keeps the iterator at the leaves of the tree instead of walking the iterator from the root each time. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 67 ++++++++++++++++++++++++++++ lib/test_xarray.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++++ lib/xarray.c | 74 +++++++++++++++++++++++++++++++ 3 files changed, 256 insertions(+) (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 0a758fa3ed2c..381f94a66762 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -828,6 +828,12 @@ static inline bool xas_not_node(struct xa_node *node) return ((unsigned long)node & 3) || !node; } +/* True if the node represents RESTART or an error */ +static inline bool xas_frozen(struct xa_node *node) +{ + return (unsigned long)node & 2; +} + /* True if the node represents head-of-tree, RESTART or BOUNDS */ static inline bool xas_top(struct xa_node *node) { @@ -1082,4 +1088,65 @@ enum { for (entry = xas_find_marked(xas, max, mark); entry; \ entry = xas_next_marked(xas, max, mark)) +void *__xas_next(struct xa_state *); +void *__xas_prev(struct xa_state *); + +/** + * xas_prev() - Move iterator to previous index. + * @xas: XArray operation state. + * + * If the @xas was in an error state, it will remain in an error state + * and this function will return %NULL. If the @xas has never been walked, + * it will have the effect of calling xas_load(). Otherwise one will be + * subtracted from the index and the state will be walked to the correct + * location in the array for the next operation. + * + * If the iterator was referencing index 0, this function wraps + * around to %ULONG_MAX. + * + * Return: The entry at the new index. This may be %NULL or an internal + * entry. + */ +static inline void *xas_prev(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (unlikely(xas_not_node(node) || node->shift || + xas->xa_offset == 0)) + return __xas_prev(xas); + + xas->xa_index--; + xas->xa_offset--; + return xa_entry(xas->xa, node, xas->xa_offset); +} + +/** + * xas_next() - Move state to next index. + * @xas: XArray operation state. + * + * If the @xas was in an error state, it will remain in an error state + * and this function will return %NULL. If the @xas has never been walked, + * it will have the effect of calling xas_load(). Otherwise one will be + * added to the index and the state will be walked to the correct + * location in the array for the next operation. + * + * If the iterator was referencing index %ULONG_MAX, this function wraps + * around to 0. + * + * Return: The entry at the new index. This may be %NULL or an internal + * entry. + */ +static inline void *xas_next(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (unlikely(xas_not_node(node) || node->shift || + xas->xa_offset == XA_CHUNK_MASK)) + return __xas_next(xas); + + xas->xa_index++; + xas->xa_offset++; + return xa_entry(xas->xa, node, xas->xa_offset); +} + #endif /* _LINUX_XARRAY_H */ diff --git a/lib/test_xarray.c b/lib/test_xarray.c index a96f67caa1c2..85ef1882dd3c 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -465,6 +465,120 @@ static noinline void check_find(struct xarray *xa) check_multi_find_2(xa); } +static noinline void check_move_small(struct xarray *xa, unsigned long idx) +{ + XA_STATE(xas, xa, 0); + unsigned long i; + + xa_store_index(xa, 0, GFP_KERNEL); + xa_store_index(xa, idx, GFP_KERNEL); + + rcu_read_lock(); + for (i = 0; i < idx * 4; i++) { + void *entry = xas_next(&xas); + if (i <= idx) + XA_BUG_ON(xa, xas.xa_node == XAS_RESTART); + XA_BUG_ON(xa, xas.xa_index != i); + if (i == 0 || i == idx) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + } + xas_next(&xas); + XA_BUG_ON(xa, xas.xa_index != i); + + do { + void *entry = xas_prev(&xas); + i--; + if (i <= idx) + XA_BUG_ON(xa, xas.xa_node == XAS_RESTART); + XA_BUG_ON(xa, xas.xa_index != i); + if (i == 0 || i == idx) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + } while (i > 0); + + xas_set(&xas, ULONG_MAX); + XA_BUG_ON(xa, xas_next(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + XA_BUG_ON(xa, xas_next(&xas) != xa_mk_value(0)); + XA_BUG_ON(xa, xas.xa_index != 0); + XA_BUG_ON(xa, xas_prev(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + rcu_read_unlock(); + + xa_erase_index(xa, 0); + xa_erase_index(xa, idx); + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_move(struct xarray *xa) +{ + XA_STATE(xas, xa, (1 << 16) - 1); + unsigned long i; + + for (i = 0; i < (1 << 16); i++) + XA_BUG_ON(xa, xa_store_index(xa, i, GFP_KERNEL) != NULL); + + rcu_read_lock(); + do { + void *entry = xas_prev(&xas); + i--; + XA_BUG_ON(xa, entry != xa_mk_value(i)); + XA_BUG_ON(xa, i != xas.xa_index); + } while (i != 0); + + XA_BUG_ON(xa, xas_prev(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + + do { + void *entry = xas_next(&xas); + XA_BUG_ON(xa, entry != xa_mk_value(i)); + XA_BUG_ON(xa, i != xas.xa_index); + i++; + } while (i < (1 << 16)); + rcu_read_unlock(); + + for (i = (1 << 8); i < (1 << 15); i++) + xa_erase_index(xa, i); + + i = xas.xa_index; + + rcu_read_lock(); + do { + void *entry = xas_prev(&xas); + i--; + if ((i < (1 << 8)) || (i >= (1 << 15))) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + XA_BUG_ON(xa, i != xas.xa_index); + } while (i != 0); + + XA_BUG_ON(xa, xas_prev(&xas) != NULL); + XA_BUG_ON(xa, xas.xa_index != ULONG_MAX); + + do { + void *entry = xas_next(&xas); + if ((i < (1 << 8)) || (i >= (1 << 15))) + XA_BUG_ON(xa, entry != xa_mk_value(i)); + else + XA_BUG_ON(xa, entry != NULL); + XA_BUG_ON(xa, i != xas.xa_index); + i++; + } while (i < (1 << 16)); + rcu_read_unlock(); + + xa_destroy(xa); + + for (i = 0; i < 16; i++) + check_move_small(xa, 1UL << i); + + for (i = 2; i < 16; i++) + check_move_small(xa, (1UL << i) - 1); +} + static noinline void check_destroy(struct xarray *xa) { unsigned long index; @@ -512,6 +626,7 @@ static int xarray_checks(void) check_multi_store(&array); check_find(&array); check_destroy(&array); + check_move(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run == tests_passed) ? 0 : -EINVAL; diff --git a/lib/xarray.c b/lib/xarray.c index 057dbe0d3bf6..303c46579598 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -876,6 +876,80 @@ void xas_pause(struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_pause); +/* + * __xas_prev() - Find the previous entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_prev() which handles all the complex cases + * out of line. + */ +void *__xas_prev(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index--; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset--; + + while (xas->xa_offset == 255) { + xas->xa_offset = xas->xa_node->offset - 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas_set_offset(xas); + } +} +EXPORT_SYMBOL_GPL(__xas_prev); + +/* + * __xas_next() - Find the next entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_next() which handles all the complex cases + * out of line. + */ +void *__xas_next(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index++; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset++; + + while (xas->xa_offset == XA_CHUNK_SIZE) { + xas->xa_offset = xas->xa_node->offset + 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas_set_offset(xas); + } +} +EXPORT_SYMBOL_GPL(__xas_next); + /** * xas_find() - Find the next present entry in the XArray. * @xas: XArray operation state. -- cgit v1.2.3 From 4e99d4e9579d3b950bf4b38d0d64eb1b9be78761 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 1 Jun 2018 22:46:02 -0400 Subject: xarray: Add xas_for_each_conflict This iterator iterates over each entry that is stored in the index or indices specified by the xa_state. This is intended for use for a conditional store of a multiindex entry, or to allow entries which are about to be removed from the xarray to be disposed of properly. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 17 +++++++++++++ lib/test_xarray.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++ lib/xarray.c | 61 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 146 insertions(+) (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 381f94a66762..2664e718dbd3 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -878,6 +878,7 @@ static inline bool xas_retry(struct xa_state *xas, const void *entry) void *xas_load(struct xa_state *); void *xas_store(struct xa_state *, void *entry); void *xas_find(struct xa_state *, unsigned long max); +void *xas_find_conflict(struct xa_state *); bool xas_get_mark(const struct xa_state *, xa_mark_t); void xas_set_mark(const struct xa_state *, xa_mark_t); @@ -1088,6 +1089,22 @@ enum { for (entry = xas_find_marked(xas, max, mark); entry; \ entry = xas_next_marked(xas, max, mark)) +/** + * xas_for_each_conflict() - Iterate over a range of an XArray. + * @xas: XArray operation state. + * @entry: Entry retrieved from the array. + * + * The loop body will be executed for each entry in the XArray that lies + * within the range specified by @xas. If the loop completes successfully, + * any entries that lie in this range will be replaced by @entry. The caller + * may break out of the loop; if they do so, the contents of the XArray will + * be unchanged. The operation may fail due to an out of memory condition. + * The caller may also call xa_set_err() to exit the loop while setting an + * error to record the reason. + */ +#define xas_for_each_conflict(xas, entry) \ + while ((entry = xas_find_conflict(xas))) + void *__xas_next(struct xa_state *); void *__xas_prev(struct xa_state *); diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 85ef1882dd3c..8eba3de1baea 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -365,6 +365,73 @@ static noinline void check_multi_store(struct xarray *xa) #endif } +static noinline void __check_store_iter(struct xarray *xa, unsigned long start, + unsigned int order, unsigned int present) +{ + XA_STATE_ORDER(xas, xa, start, order); + void *entry; + unsigned int count = 0; + +retry: + xas_lock(&xas); + xas_for_each_conflict(&xas, entry) { + XA_BUG_ON(xa, !xa_is_value(entry)); + XA_BUG_ON(xa, entry < xa_mk_value(start)); + XA_BUG_ON(xa, entry > xa_mk_value(start + (1UL << order) - 1)); + count++; + } + xas_store(&xas, xa_mk_value(start)); + xas_unlock(&xas); + if (xas_nomem(&xas, GFP_KERNEL)) { + count = 0; + goto retry; + } + XA_BUG_ON(xa, xas_error(&xas)); + XA_BUG_ON(xa, count != present); + XA_BUG_ON(xa, xa_load(xa, start) != xa_mk_value(start)); + XA_BUG_ON(xa, xa_load(xa, start + (1UL << order) - 1) != + xa_mk_value(start)); + xa_erase_index(xa, start); +} + +static noinline void check_store_iter(struct xarray *xa) +{ + unsigned int i, j; + unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 20 : 1; + + for (i = 0; i < max_order; i++) { + unsigned int min = 1 << i; + unsigned int max = (2 << i) - 1; + __check_store_iter(xa, 0, i, 0); + XA_BUG_ON(xa, !xa_empty(xa)); + __check_store_iter(xa, min, i, 0); + XA_BUG_ON(xa, !xa_empty(xa)); + + xa_store_index(xa, min, GFP_KERNEL); + __check_store_iter(xa, min, i, 1); + XA_BUG_ON(xa, !xa_empty(xa)); + xa_store_index(xa, max, GFP_KERNEL); + __check_store_iter(xa, min, i, 1); + XA_BUG_ON(xa, !xa_empty(xa)); + + for (j = 0; j < min; j++) + xa_store_index(xa, j, GFP_KERNEL); + __check_store_iter(xa, 0, i, min); + XA_BUG_ON(xa, !xa_empty(xa)); + for (j = 0; j < min; j++) + xa_store_index(xa, min + j, GFP_KERNEL); + __check_store_iter(xa, min, i, min); + XA_BUG_ON(xa, !xa_empty(xa)); + } +#ifdef CONFIG_XARRAY_MULTI + xa_store_index(xa, 63, GFP_KERNEL); + xa_store_index(xa, 65, GFP_KERNEL); + __check_store_iter(xa, 64, 2, 1); + xa_erase_index(xa, 63); +#endif + XA_BUG_ON(xa, !xa_empty(xa)); +} + static noinline void check_multi_find(struct xarray *xa) { #ifdef CONFIG_XARRAY_MULTI @@ -627,6 +694,7 @@ static int xarray_checks(void) check_find(&array); check_destroy(&array); check_move(&array); + check_store_iter(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run == tests_passed) ? 0 : -EINVAL; diff --git a/lib/xarray.c b/lib/xarray.c index 303c46579598..41f8ebc651f5 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1110,6 +1110,67 @@ max: } EXPORT_SYMBOL_GPL(xas_find_marked); +/** + * xas_find_conflict() - Find the next present entry in a range. + * @xas: XArray operation state. + * + * The @xas describes both a range and a position within that range. + * + * Context: Any context. Expects xa_lock to be held. + * Return: The next entry in the range covered by @xas or %NULL. + */ +void *xas_find_conflict(struct xa_state *xas) +{ + void *curr; + + if (xas_error(xas)) + return NULL; + + if (!xas->xa_node) + return NULL; + + if (xas_top(xas->xa_node)) { + curr = xas_start(xas); + if (!curr) + return NULL; + while (xa_is_node(curr)) { + struct xa_node *node = xa_to_node(curr); + curr = xas_descend(xas, node); + } + if (curr) + return curr; + } + + if (xas->xa_node->shift > xas->xa_shift) + return NULL; + + for (;;) { + if (xas->xa_node->shift == xas->xa_shift) { + if ((xas->xa_offset & xas->xa_sibs) == xas->xa_sibs) + break; + } else if (xas->xa_offset == XA_CHUNK_MASK) { + xas->xa_offset = xas->xa_node->offset; + xas->xa_node = xa_parent_locked(xas->xa, xas->xa_node); + if (!xas->xa_node) + break; + continue; + } + curr = xa_entry_locked(xas->xa, xas->xa_node, ++xas->xa_offset); + if (xa_is_sibling(curr)) + continue; + while (xa_is_node(curr)) { + xas->xa_node = xa_to_node(curr); + xas->xa_offset = 0; + curr = xa_entry_locked(xas->xa, xas->xa_node, 0); + } + if (curr) + return curr; + } + xas->xa_offset -= xas->xa_sibs; + return NULL; +} +EXPORT_SYMBOL_GPL(xas_find_conflict); + /** * xa_init_flags() - Initialise an empty XArray with flags. * @xa: XArray. -- cgit v1.2.3 From 2264f5132fe45571139727ebdeb78696b35d1506 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 4 Dec 2017 00:11:48 -0500 Subject: xarray: Add xas_create_range This hopefully temporary function is useful for users who have not yet been converted to multi-index entries. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 13 ++++++ lib/test_xarray.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++ lib/xarray.c | 50 +++++++++++++++++++++ 3 files changed, 182 insertions(+) (limited to 'lib/xarray.c') diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 2664e718dbd3..deae17aa0ed7 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -822,6 +822,17 @@ static inline bool xas_valid(const struct xa_state *xas) return !xas_invalid(xas); } +/** + * xas_is_node() - Does the xas point to a node? + * @xas: XArray operation state. + * + * Return: %true if the xas currently references a node. + */ +static inline bool xas_is_node(const struct xa_state *xas) +{ + return xas_valid(xas) && xas->xa_node; +} + /* True if the pointer is something other than a node */ static inline bool xas_not_node(struct xa_node *node) { @@ -889,6 +900,8 @@ void xas_init_marks(const struct xa_state *); bool xas_nomem(struct xa_state *, gfp_t); void xas_pause(struct xa_state *); +void xas_create_range(struct xa_state *); + /** * xas_reload() - Refetch an entry from the xarray. * @xas: XArray operation state. diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 8eba3de1baea..703370015d10 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -646,6 +646,124 @@ static noinline void check_move(struct xarray *xa) check_move_small(xa, (1UL << i) - 1); } +static noinline void xa_store_many_order(struct xarray *xa, + unsigned long index, unsigned order) +{ + XA_STATE_ORDER(xas, xa, index, order); + unsigned int i = 0; + + do { + xas_lock(&xas); + XA_BUG_ON(xa, xas_find_conflict(&xas)); + xas_create_range(&xas); + if (xas_error(&xas)) + goto unlock; + for (i = 0; i < (1U << order); i++) { + XA_BUG_ON(xa, xas_store(&xas, xa_mk_value(index + i))); + xas_next(&xas); + } +unlock: + xas_unlock(&xas); + } while (xas_nomem(&xas, GFP_KERNEL)); + + XA_BUG_ON(xa, xas_error(&xas)); +} + +static noinline void check_create_range_1(struct xarray *xa, + unsigned long index, unsigned order) +{ + unsigned long i; + + xa_store_many_order(xa, index, order); + for (i = index; i < index + (1UL << order); i++) + xa_erase_index(xa, i); + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_create_range_2(struct xarray *xa, unsigned order) +{ + unsigned long i; + unsigned long nr = 1UL << order; + + for (i = 0; i < nr * nr; i += nr) + xa_store_many_order(xa, i, order); + for (i = 0; i < nr * nr; i++) + xa_erase_index(xa, i); + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_create_range_3(void) +{ + XA_STATE(xas, NULL, 0); + xas_set_err(&xas, -EEXIST); + xas_create_range(&xas); + XA_BUG_ON(NULL, xas_error(&xas) != -EEXIST); +} + +static noinline void check_create_range_4(struct xarray *xa, + unsigned long index, unsigned order) +{ + XA_STATE_ORDER(xas, xa, index, order); + unsigned long base = xas.xa_index; + unsigned long i = 0; + + xa_store_index(xa, index, GFP_KERNEL); + do { + xas_lock(&xas); + xas_create_range(&xas); + if (xas_error(&xas)) + goto unlock; + for (i = 0; i < (1UL << order); i++) { + void *old = xas_store(&xas, xa_mk_value(base + i)); + if (xas.xa_index == index) + XA_BUG_ON(xa, old != xa_mk_value(base + i)); + else + XA_BUG_ON(xa, old != NULL); + xas_next(&xas); + } +unlock: + xas_unlock(&xas); + } while (xas_nomem(&xas, GFP_KERNEL)); + + XA_BUG_ON(xa, xas_error(&xas)); + + for (i = base; i < base + (1UL << order); i++) + xa_erase_index(xa, i); + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_create_range(struct xarray *xa) +{ + unsigned int order; + unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 12 : 1; + + for (order = 0; order < max_order; order++) { + check_create_range_1(xa, 0, order); + check_create_range_1(xa, 1U << order, order); + check_create_range_1(xa, 2U << order, order); + check_create_range_1(xa, 3U << order, order); + check_create_range_1(xa, 1U << 24, order); + if (order < 10) + check_create_range_2(xa, order); + + check_create_range_4(xa, 0, order); + check_create_range_4(xa, 1U << order, order); + check_create_range_4(xa, 2U << order, order); + check_create_range_4(xa, 3U << order, order); + check_create_range_4(xa, 1U << 24, order); + + check_create_range_4(xa, 1, order); + check_create_range_4(xa, (1U << order) + 1, order); + check_create_range_4(xa, (2U << order) + 1, order); + check_create_range_4(xa, (2U << order) - 1, order); + check_create_range_4(xa, (3U << order) + 1, order); + check_create_range_4(xa, (3U << order) - 1, order); + check_create_range_4(xa, (1U << 24) + 1, order); + } + + check_create_range_3(); +} + static noinline void check_destroy(struct xarray *xa) { unsigned long index; @@ -694,6 +812,7 @@ static int xarray_checks(void) check_find(&array); check_destroy(&array); check_move(&array); + check_create_range(&array); check_store_iter(&array); printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); diff --git a/lib/xarray.c b/lib/xarray.c index 41f8ebc651f5..ff37516fe832 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -637,6 +637,56 @@ static void *xas_create(struct xa_state *xas) return entry; } +/** + * xas_create_range() - Ensure that stores to this range will succeed + * @xas: XArray operation state. + * + * Creates all of the slots in the range covered by @xas. Sets @xas to + * create single-index entries and positions it at the beginning of the + * range. This is for the benefit of users which have not yet been + * converted to use multi-index entries. + */ +void xas_create_range(struct xa_state *xas) +{ + unsigned long index = xas->xa_index; + unsigned char shift = xas->xa_shift; + unsigned char sibs = xas->xa_sibs; + + xas->xa_index |= ((sibs + 1) << shift) - 1; + if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift) + xas->xa_offset |= sibs; + xas->xa_shift = 0; + xas->xa_sibs = 0; + + for (;;) { + xas_create(xas); + if (xas_error(xas)) + goto restore; + if (xas->xa_index <= (index | XA_CHUNK_MASK)) + goto success; + xas->xa_index -= XA_CHUNK_SIZE; + + for (;;) { + struct xa_node *node = xas->xa_node; + xas->xa_node = xa_parent_locked(xas->xa, node); + xas->xa_offset = node->offset - 1; + if (node->offset != 0) + break; + } + } + +restore: + xas->xa_shift = shift; + xas->xa_sibs = sibs; + xas->xa_index = index; + return; +success: + xas->xa_index = index; + if (xas->xa_node) + xas_set_offset(xas); +} +EXPORT_SYMBOL_GPL(xas_create_range); + static void update_node(struct xa_state *xas, struct xa_node *node, int count, int values) { -- cgit v1.2.3 From 9f14d4f1f1045f161fd4db8a8e194b7825c2874a Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 1 Oct 2018 14:54:59 -0400 Subject: xarray: Add xa_reserve and xa_release This function reserves a slot in the XArray for users which need to acquire multiple locks before storing their entry in the tree and so cannot use a plain xa_store(). Signed-off-by: Matthew Wilcox --- Documentation/core-api/xarray.rst | 6 +++++ include/linux/xarray.h | 34 ++++++++++++++++++++++++++-- lib/test_xarray.c | 40 +++++++++++++++++++++++++++++++++ lib/xarray.c | 47 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 125 insertions(+), 2 deletions(-) (limited to 'lib/xarray.c') diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst index 4b101b4f3aa1..2b397da84bcd 100644 --- a/Documentation/core-api/xarray.rst +++ b/Documentation/core-api/xarray.rst @@ -293,6 +293,12 @@ to :c:func:`xas_retry`, and retry the operation if it returns ``true``. of this RCU period. You should restart the lookup from the head of the array. + * - Zero + - :c:func:`xa_is_zero` + - Zero entries appear as ``NULL`` through the Normal API, but occupy + an entry in the XArray which can be used to reserve the index for + future use. + Other internal entries may be added in the future. As far as possible, they will be handled by :c:func:`xas_retry`. diff --git a/include/linux/xarray.h b/include/linux/xarray.h index deae17aa0ed7..bed63d3cfea8 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -32,7 +32,8 @@ * The following internal entries have a special meaning: * * 0-62: Sibling entries - * 256: Retry entry + * 256: Zero entry + * 257: Retry entry * * Errors are also represented as internal entries, but use the negative * space (-4094 to -2). They're never stored in the slots array; only @@ -277,6 +278,7 @@ void *xa_load(struct xarray *, unsigned long index); void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); void *xa_cmpxchg(struct xarray *, unsigned long index, void *old, void *entry, gfp_t); +int xa_reserve(struct xarray *, unsigned long index, gfp_t); bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); @@ -371,6 +373,20 @@ static inline int xa_insert(struct xarray *xa, unsigned long index, return -EEXIST; } +/** + * xa_release() - Release a reserved entry. + * @xa: XArray. + * @index: Index of entry. + * + * After calling xa_reserve(), you can call this function to release the + * reservation. If the entry at @index has been stored to, this function + * will do nothing. + */ +static inline void xa_release(struct xarray *xa, unsigned long index) +{ + xa_cmpxchg(xa, index, NULL, NULL, 0); +} + /** * xa_for_each() - Iterate over a portion of an XArray. * @xa: XArray. @@ -658,7 +674,19 @@ static inline bool xa_is_sibling(const void *entry) (entry < xa_mk_sibling(XA_CHUNK_SIZE - 1)); } -#define XA_RETRY_ENTRY xa_mk_internal(256) +#define XA_ZERO_ENTRY xa_mk_internal(256) +#define XA_RETRY_ENTRY xa_mk_internal(257) + +/** + * xa_is_zero() - Is the entry a zero entry? + * @entry: Entry retrieved from the XArray + * + * Return: %true if the entry is a zero entry. + */ +static inline bool xa_is_zero(const void *entry) +{ + return unlikely(entry == XA_ZERO_ENTRY); +} /** * xa_is_retry() - Is the entry a retry entry? @@ -880,6 +908,8 @@ static inline void xas_reset(struct xa_state *xas) */ static inline bool xas_retry(struct xa_state *xas, const void *entry) { + if (xa_is_zero(entry)) + return true; if (!xa_is_retry(entry)) return false; xas_reset(xas); diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 703370015d10..6aafd411a5c3 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -259,6 +259,45 @@ static noinline void check_cmpxchg(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_reserve(struct xarray *xa) +{ + void *entry; + unsigned long index = 0; + + /* An array with a reserved entry is not empty */ + XA_BUG_ON(xa, !xa_empty(xa)); + xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_empty(xa)); + XA_BUG_ON(xa, xa_load(xa, 12345678)); + xa_release(xa, 12345678); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Releasing a used entry does nothing */ + xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_NOWAIT) != NULL); + xa_release(xa, 12345678); + xa_erase_index(xa, 12345678); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* cmpxchg sees a reserved entry as NULL */ + xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, NULL, xa_mk_value(12345678), + GFP_NOWAIT) != NULL); + xa_release(xa, 12345678); + xa_erase_index(xa, 12345678); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Can iterate through a reserved entry */ + xa_store_index(xa, 5, GFP_KERNEL); + xa_reserve(xa, 6, GFP_KERNEL); + xa_store_index(xa, 7, GFP_KERNEL); + + xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) { + XA_BUG_ON(xa, index != 5 && index != 7); + } + xa_destroy(xa); +} + static noinline void check_xas_erase(struct xarray *xa) { XA_STATE(xas, xa, 0); @@ -808,6 +847,7 @@ static int xarray_checks(void) check_xa_shrink(&array); check_xas_erase(&array); check_cmpxchg(&array); + check_reserve(&array); check_multi_store(&array); check_find(&array); check_destroy(&array); diff --git a/lib/xarray.c b/lib/xarray.c index ff37516fe832..546461914282 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1266,6 +1266,8 @@ void *xa_load(struct xarray *xa, unsigned long index) rcu_read_lock(); do { entry = xas_load(&xas); + if (xa_is_zero(entry)) + entry = NULL; } while (xas_retry(&xas, entry)); rcu_read_unlock(); @@ -1275,6 +1277,8 @@ EXPORT_SYMBOL(xa_load); static void *xas_result(struct xa_state *xas, void *curr) { + if (xa_is_zero(curr)) + return NULL; XA_NODE_BUG_ON(xas->xa_node, xa_is_internal(curr)); if (xas_error(xas)) curr = xas->xa_node; @@ -1394,6 +1398,8 @@ void *xa_cmpxchg(struct xarray *xa, unsigned long index, do { xas_lock(&xas); curr = xas_load(&xas); + if (curr == XA_ZERO_ENTRY) + curr = NULL; if (curr == old) xas_store(&xas, entry); xas_unlock(&xas); @@ -1430,6 +1436,8 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, do { curr = xas_load(&xas); + if (curr == XA_ZERO_ENTRY) + curr = NULL; if (curr == old) xas_store(&xas, entry); } while (__xas_nomem(&xas, gfp)); @@ -1438,6 +1446,43 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, } EXPORT_SYMBOL(__xa_cmpxchg); +/** + * xa_reserve() - Reserve this index in the XArray. + * @xa: XArray. + * @index: Index into array. + * @gfp: Memory allocation flags. + * + * Ensures there is somewhere to store an entry at @index in the array. + * If there is already something stored at @index, this function does + * nothing. If there was nothing there, the entry is marked as reserved. + * Loads from @index will continue to see a %NULL pointer until a + * subsequent store to @index. + * + * If you do not use the entry that you have reserved, call xa_release() + * or xa_erase() to free any unnecessary memory. + * + * Context: Process context. Takes and releases the xa_lock, IRQ or BH safe + * if specified in XArray flags. May sleep if the @gfp flags permit. + * Return: 0 if the reservation succeeded or -ENOMEM if it failed. + */ +int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) +{ + XA_STATE(xas, xa, index); + unsigned int lock_type = xa_lock_type(xa); + void *curr; + + do { + xas_lock_type(&xas, lock_type); + curr = xas_load(&xas); + if (!curr) + xas_store(&xas, XA_ZERO_ENTRY); + xas_unlock_type(&xas, lock_type); + } while (xas_nomem(&xas, gfp)); + + return xas_error(&xas); +} +EXPORT_SYMBOL(xa_reserve); + /** * __xa_set_mark() - Set this mark on this entry while locked. * @xa: XArray. @@ -1797,6 +1842,8 @@ void xa_dump_entry(const void *entry, unsigned long index, unsigned long shift) pr_cont("retry (%ld)\n", xa_to_internal(entry)); else if (xa_is_sibling(entry)) pr_cont("sibling (slot %ld)\n", xa_to_sibling(entry)); + else if (xa_is_zero(entry)) + pr_cont("zero (%ld)\n", xa_to_internal(entry)); else pr_cont("UNKNOWN ENTRY (%px)\n", entry); } -- cgit v1.2.3 From 371c752dc66948714ee3b66c3306f3ff1ff71d2e Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 4 Jul 2018 10:50:12 -0400 Subject: xarray: Track free entries in an XArray Add the optional ability to track which entries in an XArray are free and provide xa_alloc() to replace most of the functionality of the IDR. Signed-off-by: Matthew Wilcox --- Documentation/core-api/xarray.rst | 23 +++++++-- include/linux/xarray.h | 101 ++++++++++++++++++++++++++++++++++++++ lib/test_xarray.c | 61 +++++++++++++++++++++++ lib/xarray.c | 88 +++++++++++++++++++++++++++++++-- 4 files changed, 266 insertions(+), 7 deletions(-) (limited to 'lib/xarray.c') diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst index 2b397da84bcd..463e4c798ec1 100644 --- a/Documentation/core-api/xarray.rst +++ b/Documentation/core-api/xarray.rst @@ -103,12 +103,25 @@ Finally, you can remove all entries from an XArray by calling to free the entries first. You can do this by iterating over all present entries in the XArray using the :c:func:`xa_for_each` iterator. +ID assignment +------------- + +You can call :c:func:`xa_alloc` to store the entry at any unused index +in the XArray. If you need to modify the array from interrupt context, +you can use :c:func:`xa_alloc_bh` or :c:func:`xa_alloc_irq` to disable +interrupts while allocating the ID. Unlike :c:func:`xa_store`, allocating +a ``NULL`` pointer does not delete an entry. Instead it reserves an +entry like :c:func:`xa_reserve` and you can release it using either +:c:func:`xa_erase` or :c:func:`xa_release`. To use ID assignment, the +XArray must be defined with :c:func:`DEFINE_XARRAY_ALLOC`, or initialised +by passing ``XA_FLAGS_ALLOC`` to :c:func:`xa_init_flags`, + Memory allocation ----------------- -The :c:func:`xa_store`, :c:func:`xa_cmpxchg`, :c:func:`xa_reserve` -and :c:func:`xa_insert` functions take a gfp_t parameter in case -the XArray needs to allocate memory to store this entry. +The :c:func:`xa_store`, :c:func:`xa_cmpxchg`, :c:func:`xa_alloc`, +:c:func:`xa_reserve` and :c:func:`xa_insert` functions take a gfp_t +parameter in case the XArray needs to allocate memory to store this entry. If the entry is being deleted, no memory allocation needs to be performed, and the GFP flags specified will be ignored. @@ -143,6 +156,9 @@ Takes xa_lock internally: * :c:func:`xa_erase_bh` * :c:func:`xa_erase_irq` * :c:func:`xa_cmpxchg` + * :c:func:`xa_alloc` + * :c:func:`xa_alloc_bh` + * :c:func:`xa_alloc_irq` * :c:func:`xa_destroy` * :c:func:`xa_set_mark` * :c:func:`xa_clear_mark` @@ -152,6 +168,7 @@ Assumes xa_lock held on entry: * :c:func:`__xa_insert` * :c:func:`__xa_erase` * :c:func:`__xa_cmpxchg` + * :c:func:`__xa_alloc` * :c:func:`__xa_set_mark` * :c:func:`__xa_clear_mark` diff --git a/include/linux/xarray.h b/include/linux/xarray.h index bed63d3cfea8..e0b57af52e9b 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -205,6 +205,7 @@ typedef unsigned __bitwise xa_mark_t; #define XA_MARK_2 ((__force xa_mark_t)2U) #define XA_PRESENT ((__force xa_mark_t)8U) #define XA_MARK_MAX XA_MARK_2 +#define XA_FREE_MARK XA_MARK_0 enum xa_lock_type { XA_LOCK_IRQ = 1, @@ -217,9 +218,12 @@ enum xa_lock_type { */ #define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ) #define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH) +#define XA_FLAGS_TRACK_FREE ((__force gfp_t)4U) #define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \ (__force unsigned)(mark))) +#define XA_FLAGS_ALLOC (XA_FLAGS_TRACK_FREE | XA_FLAGS_MARK(XA_FREE_MARK)) + /** * struct xarray - The anchor of the XArray. * @xa_lock: Lock that protects the contents of the XArray. @@ -273,6 +277,15 @@ struct xarray { */ #define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0) +/** + * DEFINE_XARRAY_ALLOC() - Define an XArray which can allocate IDs. + * @name: A string that names your XArray. + * + * This is intended for file scope definitions of allocating XArrays. + * See also DEFINE_XARRAY(). + */ +#define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC) + void xa_init_flags(struct xarray *, gfp_t flags); void *xa_load(struct xarray *, unsigned long index); void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); @@ -439,6 +452,7 @@ void *__xa_erase(struct xarray *, unsigned long index); void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old, void *entry, gfp_t); +int __xa_alloc(struct xarray *, u32 *id, u32 max, void *entry, gfp_t); void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); @@ -518,6 +532,93 @@ static inline void *xa_erase_irq(struct xarray *xa, unsigned long index) return entry; } +/** + * xa_alloc() - Find somewhere to store this entry in the XArray. + * @xa: XArray. + * @id: Pointer to ID. + * @max: Maximum ID to allocate (inclusive). + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * Allocates an unused ID in the range specified by @id and @max. + * Updates the @id pointer with the index, then stores the entry at that + * index. A concurrent lookup will not see an uninitialised @id. + * + * Context: Process context. Takes and releases the xa_lock. May sleep if + * the @gfp flags permit. + * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if + * there is no more space in the XArray. + */ +static inline int xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, + gfp_t gfp) +{ + int err; + + xa_lock(xa); + err = __xa_alloc(xa, id, max, entry, gfp); + xa_unlock(xa); + + return err; +} + +/** + * xa_alloc_bh() - Find somewhere to store this entry in the XArray. + * @xa: XArray. + * @id: Pointer to ID. + * @max: Maximum ID to allocate (inclusive). + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * Allocates an unused ID in the range specified by @id and @max. + * Updates the @id pointer with the index, then stores the entry at that + * index. A concurrent lookup will not see an uninitialised @id. + * + * Context: Process context. Takes and releases the xa_lock while + * disabling softirqs. May sleep if the @gfp flags permit. + * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if + * there is no more space in the XArray. + */ +static inline int xa_alloc_bh(struct xarray *xa, u32 *id, u32 max, void *entry, + gfp_t gfp) +{ + int err; + + xa_lock_bh(xa); + err = __xa_alloc(xa, id, max, entry, gfp); + xa_unlock_bh(xa); + + return err; +} + +/** + * xa_alloc_irq() - Find somewhere to store this entry in the XArray. + * @xa: XArray. + * @id: Pointer to ID. + * @max: Maximum ID to allocate (inclusive). + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * Allocates an unused ID in the range specified by @id and @max. + * Updates the @id pointer with the index, then stores the entry at that + * index. A concurrent lookup will not see an uninitialised @id. + * + * Context: Process context. Takes and releases the xa_lock while + * disabling interrupts. May sleep if the @gfp flags permit. + * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if + * there is no more space in the XArray. + */ +static inline int xa_alloc_irq(struct xarray *xa, u32 *id, u32 max, void *entry, + gfp_t gfp) +{ + int err; + + xa_lock_irq(xa); + err = __xa_alloc(xa, id, max, entry, gfp); + xa_unlock_irq(xa); + + return err; +} + /* Everything below here is the Advanced API. Proceed with caution. */ /* diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 6aafd411a5c3..a752e6a37e6f 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -33,6 +33,15 @@ static void *xa_store_index(struct xarray *xa, unsigned long index, gfp_t gfp) return xa_store(xa, index, xa_mk_value(index & LONG_MAX), gfp); } +static void xa_alloc_index(struct xarray *xa, unsigned long index, gfp_t gfp) +{ + u32 id = 0; + + XA_BUG_ON(xa, xa_alloc(xa, &id, UINT_MAX, xa_mk_value(index & LONG_MAX), + gfp) != 0); + XA_BUG_ON(xa, id != index); +} + static void xa_erase_index(struct xarray *xa, unsigned long index) { XA_BUG_ON(xa, xa_erase(xa, index) != xa_mk_value(index & LONG_MAX)); @@ -404,6 +413,57 @@ static noinline void check_multi_store(struct xarray *xa) #endif } +static DEFINE_XARRAY_ALLOC(xa0); + +static noinline void check_xa_alloc(void) +{ + int i; + u32 id; + + /* An empty array should assign 0 to the first alloc */ + xa_alloc_index(&xa0, 0, GFP_KERNEL); + + /* Erasing it should make the array empty again */ + xa_erase_index(&xa0, 0); + XA_BUG_ON(&xa0, !xa_empty(&xa0)); + + /* And it should assign 0 again */ + xa_alloc_index(&xa0, 0, GFP_KERNEL); + + /* The next assigned ID should be 1 */ + xa_alloc_index(&xa0, 1, GFP_KERNEL); + xa_erase_index(&xa0, 1); + + /* Storing a value should mark it used */ + xa_store_index(&xa0, 1, GFP_KERNEL); + xa_alloc_index(&xa0, 2, GFP_KERNEL); + + /* If we then erase 0, it should be free */ + xa_erase_index(&xa0, 0); + xa_alloc_index(&xa0, 0, GFP_KERNEL); + + xa_erase_index(&xa0, 1); + xa_erase_index(&xa0, 2); + + for (i = 1; i < 5000; i++) { + xa_alloc_index(&xa0, i, GFP_KERNEL); + } + + xa_destroy(&xa0); + + id = 0xfffffffeU; + XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, UINT_MAX, xa_mk_value(0), + GFP_KERNEL) != 0); + XA_BUG_ON(&xa0, id != 0xfffffffeU); + XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, UINT_MAX, xa_mk_value(0), + GFP_KERNEL) != 0); + XA_BUG_ON(&xa0, id != 0xffffffffU); + XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, UINT_MAX, xa_mk_value(0), + GFP_KERNEL) != -ENOSPC); + XA_BUG_ON(&xa0, id != 0xffffffffU); + xa_destroy(&xa0); +} + static noinline void __check_store_iter(struct xarray *xa, unsigned long start, unsigned int order, unsigned int present) { @@ -849,6 +909,7 @@ static int xarray_checks(void) check_cmpxchg(&array); check_reserve(&array); check_multi_store(&array); + check_xa_alloc(); check_find(&array); check_destroy(&array); check_move(&array); diff --git a/lib/xarray.c b/lib/xarray.c index 546461914282..9a0d49d4b5f0 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -52,6 +52,11 @@ static inline void xas_unlock_type(struct xa_state *xas, unsigned int lock_type) xas_unlock(xas); } +static inline bool xa_track_free(const struct xarray *xa) +{ + return xa->xa_flags & XA_FLAGS_TRACK_FREE; +} + static inline void xa_mark_set(struct xarray *xa, xa_mark_t mark) { if (!(xa->xa_flags & XA_FLAGS_MARK(mark))) @@ -94,6 +99,11 @@ static inline bool node_any_mark(struct xa_node *node, xa_mark_t mark) return !bitmap_empty(node_marks(node, mark), XA_CHUNK_SIZE); } +static inline void node_mark_all(struct xa_node *node, xa_mark_t mark) +{ + bitmap_fill(node_marks(node, mark), XA_CHUNK_SIZE); +} + #define mark_inc(mark) do { \ mark = (__force xa_mark_t)((__force unsigned)(mark) + 1); \ } while (0) @@ -416,6 +426,8 @@ static void xas_shrink(struct xa_state *xas) xas->xa_node = XAS_BOUNDS; RCU_INIT_POINTER(xa->xa_head, entry); + if (xa_track_free(xa) && !node_get_mark(node, 0, XA_FREE_MARK)) + xa_mark_clear(xa, XA_FREE_MARK); node->count = 0; node->nr_values = 0; @@ -549,8 +561,15 @@ static int xas_expand(struct xa_state *xas, void *head) /* Propagate the aggregated mark info to the new child */ for (;;) { - if (xa_marked(xa, mark)) + if (xa_track_free(xa) && mark == XA_FREE_MARK) { + node_mark_all(node, XA_FREE_MARK); + if (!xa_marked(xa, XA_FREE_MARK)) { + node_clear_mark(node, 0, XA_FREE_MARK); + xa_mark_set(xa, XA_FREE_MARK); + } + } else if (xa_marked(xa, mark)) { node_set_mark(node, 0, mark); + } if (mark == XA_MARK_MAX) break; mark_inc(mark); @@ -624,6 +643,8 @@ static void *xas_create(struct xa_state *xas) node = xas_alloc(xas, shift); if (!node) break; + if (xa_track_free(xa)) + node_mark_all(node, XA_FREE_MARK); rcu_assign_pointer(*slot, xa_mk_node(node)); } else if (xa_is_node(entry)) { node = xa_to_node(entry); @@ -882,7 +903,10 @@ void xas_init_marks(const struct xa_state *xas) xa_mark_t mark = 0; for (;;) { - xas_clear_mark(xas, mark); + if (xa_track_free(xas->xa) && mark == XA_FREE_MARK) + xas_set_mark(xas, mark); + else + xas_clear_mark(xas, mark); if (mark == XA_MARK_MAX) break; mark_inc(mark); @@ -1333,6 +1357,8 @@ void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) do { xas_lock(&xas); curr = xas_store(&xas, entry); + if (xa_track_free(xa) && entry) + xas_clear_mark(&xas, XA_FREE_MARK); xas_unlock(&xas); } while (xas_nomem(&xas, gfp)); @@ -1365,6 +1391,8 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) do { curr = xas_store(&xas, entry); + if (xa_track_free(xa) && entry) + xas_clear_mark(&xas, XA_FREE_MARK); } while (__xas_nomem(&xas, gfp)); return xas_result(&xas, curr); @@ -1400,8 +1428,11 @@ void *xa_cmpxchg(struct xarray *xa, unsigned long index, curr = xas_load(&xas); if (curr == XA_ZERO_ENTRY) curr = NULL; - if (curr == old) + if (curr == old) { xas_store(&xas, entry); + if (xa_track_free(xa) && entry) + xas_clear_mark(&xas, XA_FREE_MARK); + } xas_unlock(&xas); } while (xas_nomem(&xas, gfp)); @@ -1438,8 +1469,11 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, curr = xas_load(&xas); if (curr == XA_ZERO_ENTRY) curr = NULL; - if (curr == old) + if (curr == old) { xas_store(&xas, entry); + if (xa_track_free(xa) && entry) + xas_clear_mark(&xas, XA_FREE_MARK); + } } while (__xas_nomem(&xas, gfp)); return xas_result(&xas, curr); @@ -1483,6 +1517,52 @@ int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) } EXPORT_SYMBOL(xa_reserve); +/** + * __xa_alloc() - Find somewhere to store this entry in the XArray. + * @xa: XArray. + * @id: Pointer to ID. + * @max: Maximum ID to allocate (inclusive). + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * Allocates an unused ID in the range specified by @id and @max. + * Updates the @id pointer with the index, then stores the entry at that + * index. A concurrent lookup will not see an uninitialised @id. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if @gfp flags permit. + * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if + * there is no more space in the XArray. + */ +int __xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, 0); + int err; + + if (WARN_ON_ONCE(xa_is_internal(entry))) + return -EINVAL; + if (WARN_ON_ONCE(!xa_track_free(xa))) + return -EINVAL; + + if (!entry) + entry = XA_ZERO_ENTRY; + + do { + xas.xa_index = *id; + xas_find_marked(&xas, max, XA_FREE_MARK); + if (xas.xa_node == XAS_RESTART) + xas_set_err(&xas, -ENOSPC); + xas_store(&xas, entry); + xas_clear_mark(&xas, XA_FREE_MARK); + } while (__xas_nomem(&xas, gfp)); + + err = xas_error(&xas); + if (!err) + *id = xas.xa_index; + return err; +} +EXPORT_SYMBOL(__xa_alloc); + /** * __xa_set_mark() - Set this mark on this entry while locked. * @xa: XArray. -- cgit v1.2.3 From 0e9446c35a80931044b6d8d2d74a9cabd248539f Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 15 Aug 2018 14:13:29 -0400 Subject: xarray: Add range store functionality This version of xa_store_range() really only supports load and store. Our only user only needs basic load and store functionality, so there's no need to do the extra work to support marking and overlapping stores correctly yet. Signed-off-by: Matthew Wilcox --- Documentation/core-api/xarray.rst | 8 ++++ include/linux/xarray.h | 2 + lib/test_xarray.c | 34 ++++++++++++++ lib/xarray.c | 97 ++++++++++++++++++++++++++++++++++++++- 4 files changed, 139 insertions(+), 2 deletions(-) (limited to 'lib/xarray.c') diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst index 463e4c798ec1..a4e705108f42 100644 --- a/Documentation/core-api/xarray.rst +++ b/Documentation/core-api/xarray.rst @@ -98,6 +98,13 @@ the XArray by calling :c:func:`xa_for_each`. You may prefer to use :c:func:`xa_find` or :c:func:`xa_find_after` to move to the next present entry in the XArray. +Calling :c:func:`xa_store_range` stores the same entry in a range +of indices. If you do this, some of the other operations will behave +in a slightly odd way. For example, marking the entry at one index +may result in the entry being marked at some, but not all of the other +indices. Storing into one index may result in the entry retrieved by +some, but not all of the other indices changing. + Finally, you can remove all entries from an XArray by calling :c:func:`xa_destroy`. If the XArray entries are pointers, you may wish to free the entries first. You can do this by iterating over all present @@ -156,6 +163,7 @@ Takes xa_lock internally: * :c:func:`xa_erase_bh` * :c:func:`xa_erase_irq` * :c:func:`xa_cmpxchg` + * :c:func:`xa_store_range` * :c:func:`xa_alloc` * :c:func:`xa_alloc_bh` * :c:func:`xa_alloc_irq` diff --git a/include/linux/xarray.h b/include/linux/xarray.h index e0b57af52e9b..d9514928ddac 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -292,6 +292,8 @@ void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); void *xa_cmpxchg(struct xarray *, unsigned long index, void *old, void *entry, gfp_t); int xa_reserve(struct xarray *, unsigned long index, gfp_t); +void *xa_store_range(struct xarray *, unsigned long first, unsigned long last, + void *entry, gfp_t); bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 0f06a93b4d0e..aa47754150ce 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -1039,6 +1039,39 @@ static noinline void check_create_range(struct xarray *xa) check_create_range_3(); } +static noinline void __check_store_range(struct xarray *xa, unsigned long first, + unsigned long last) +{ +#ifdef CONFIG_XARRAY_MULTI + xa_store_range(xa, first, last, xa_mk_value(first), GFP_KERNEL); + + XA_BUG_ON(xa, xa_load(xa, first) != xa_mk_value(first)); + XA_BUG_ON(xa, xa_load(xa, last) != xa_mk_value(first)); + XA_BUG_ON(xa, xa_load(xa, first - 1) != NULL); + XA_BUG_ON(xa, xa_load(xa, last + 1) != NULL); + + xa_store_range(xa, first, last, NULL, GFP_KERNEL); +#endif + + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_store_range(struct xarray *xa) +{ + unsigned long i, j; + + for (i = 0; i < 128; i++) { + for (j = i; j < 128; j++) { + __check_store_range(xa, i, j); + __check_store_range(xa, 128 + i, 128 + j); + __check_store_range(xa, 4095 + i, 4095 + j); + __check_store_range(xa, 4096 + i, 4096 + j); + __check_store_range(xa, 123456 + i, 123456 + j); + __check_store_range(xa, UINT_MAX + i, UINT_MAX + j); + } + } +} + static LIST_HEAD(shadow_nodes); static void test_update_node(struct xa_node *node) @@ -1184,6 +1217,7 @@ static int xarray_checks(void) check_destroy(&array); check_move(&array); check_create_range(&array); + check_store_range(&array); check_store_iter(&array); check_workingset(&array, 0); diff --git a/lib/xarray.c b/lib/xarray.c index 9a0d49d4b5f0..8b176f009c08 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -376,6 +376,14 @@ static void *xas_alloc(struct xa_state *xas, unsigned int shift) return node; } +#ifdef CONFIG_XARRAY_MULTI +/* Returns the number of indices covered by a given xa_state */ +static unsigned long xas_size(const struct xa_state *xas) +{ + return (xas->xa_sibs + 1UL) << xas->xa_shift; +} +#endif + /* * Use this to calculate the maximum index that will need to be created * in order to add the entry described by @xas. Because we cannot store a @@ -388,8 +396,7 @@ static unsigned long xas_max(struct xa_state *xas) #ifdef CONFIG_XARRAY_MULTI if (xas->xa_shift || xas->xa_sibs) { - unsigned long mask; - mask = (((xas->xa_sibs + 1UL) << xas->xa_shift) - 1); + unsigned long mask = xas_size(xas) - 1; max |= mask; if (mask == max) max++; @@ -1517,6 +1524,92 @@ int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) } EXPORT_SYMBOL(xa_reserve); +#ifdef CONFIG_XARRAY_MULTI +static void xas_set_range(struct xa_state *xas, unsigned long first, + unsigned long last) +{ + unsigned int shift = 0; + unsigned long sibs = last - first; + unsigned int offset = XA_CHUNK_MASK; + + xas_set(xas, first); + + while ((first & XA_CHUNK_MASK) == 0) { + if (sibs < XA_CHUNK_MASK) + break; + if ((sibs == XA_CHUNK_MASK) && (offset < XA_CHUNK_MASK)) + break; + shift += XA_CHUNK_SHIFT; + if (offset == XA_CHUNK_MASK) + offset = sibs & XA_CHUNK_MASK; + sibs >>= XA_CHUNK_SHIFT; + first >>= XA_CHUNK_SHIFT; + } + + offset = first & XA_CHUNK_MASK; + if (offset + sibs > XA_CHUNK_MASK) + sibs = XA_CHUNK_MASK - offset; + if ((((first + sibs + 1) << shift) - 1) > last) + sibs -= 1; + + xas->xa_shift = shift; + xas->xa_sibs = sibs; +} + +/** + * xa_store_range() - Store this entry at a range of indices in the XArray. + * @xa: XArray. + * @first: First index to affect. + * @last: Last index to affect. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * After this function returns, loads from any index between @first and @last, + * inclusive will return @entry. + * Storing into an existing multislot entry updates the entry of every index. + * The marks associated with @index are unaffected unless @entry is %NULL. + * + * Context: Process context. Takes and releases the xa_lock. May sleep + * if the @gfp flags permit. + * Return: %NULL on success, xa_err(-EINVAL) if @entry cannot be stored in + * an XArray, or xa_err(-ENOMEM) if memory allocation failed. + */ +void *xa_store_range(struct xarray *xa, unsigned long first, + unsigned long last, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, 0); + + if (WARN_ON_ONCE(xa_is_internal(entry))) + return XA_ERROR(-EINVAL); + if (last < first) + return XA_ERROR(-EINVAL); + + do { + xas_lock(&xas); + if (entry) { + unsigned int order = (last == ~0UL) ? 64 : + ilog2(last + 1); + xas_set_order(&xas, last, order); + xas_create(&xas); + if (xas_error(&xas)) + goto unlock; + } + do { + xas_set_range(&xas, first, last); + xas_store(&xas, entry); + if (xas_error(&xas)) + goto unlock; + first += xas_size(&xas); + } while (first <= last); +unlock: + xas_unlock(&xas); + } while (xas_nomem(&xas, gfp)); + + return xas_result(&xas, NULL); +} +EXPORT_SYMBOL(xa_store_range); +#endif /* CONFIG_XARRAY_MULTI */ + /** * __xa_alloc() - Find somewhere to store this entry in the XArray. * @xa: XArray. -- cgit v1.2.3