[PATCH] dm: add exports

Move definitions of core device-mapper functions for manipulating mapped
devices and their tables to <linux/device-mapper.h> advertising their
availability for use elsewhere in the kernel.

Protect the contents of device-mapper.h with ifdef __KERNEL__.  And throw
in a few formatting clean-ups and extra comments.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 102 insertions, 2 deletions

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index aee10b2ea4c..010c8c5eeb3 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -8,9 +8,12 @@
 #ifndef _LINUX_DEVICE_MAPPER_H
 #define _LINUX_DEVICE_MAPPER_H
 
+#ifdef __KERNEL__
+
 struct dm_target;
 struct dm_table;
 struct dm_dev;
+struct mapped_device;
 
 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
 
@@ -78,7 +81,7 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d);
 struct target_type {
 	const char *name;
 	struct module *module;
-        unsigned version[3];
+	unsigned version[3];
 	dm_ctr_fn ctr;
 	dm_dtr_fn dtr;
 	dm_map_fn map;
@@ -128,4 +131,101 @@ struct dm_target {
 int dm_register_target(struct target_type *t);
 int dm_unregister_target(struct target_type *t);
 
-#endif				/* _LINUX_DEVICE_MAPPER_H */
+
+/*-----------------------------------------------------------------
+ * Functions for creating and manipulating mapped devices.
+ * Drop the reference with dm_put when you finish with the object.
+ *---------------------------------------------------------------*/
+
+/*
+ * DM_ANY_MINOR chooses the next available minor number.
+ */
+#define DM_ANY_MINOR (-1)
+int dm_create(int minor, struct mapped_device **md);
+
+/*
+ * Reference counting for md.
+ */
+struct mapped_device *dm_get_md(dev_t dev);
+void dm_get(struct mapped_device *md);
+void dm_put(struct mapped_device *md);
+
+/*
+ * An arbitrary pointer may be stored alongside a mapped device.
+ */
+void dm_set_mdptr(struct mapped_device *md, void *ptr);
+void *dm_get_mdptr(struct mapped_device *md);
+
+/*
+ * A device can still be used while suspended, but I/O is deferred.
+ */
+int dm_suspend(struct mapped_device *md, int with_lockfs);
+int dm_resume(struct mapped_device *md);
+
+/*
+ * Event functions.
+ */
+uint32_t dm_get_event_nr(struct mapped_device *md);
+int dm_wait_event(struct mapped_device *md, int event_nr);
+
+/*
+ * Info functions.
+ */
+struct gendisk *dm_disk(struct mapped_device *md);
+int dm_suspended(struct mapped_device *md);
+
+/*
+ * Geometry functions.
+ */
+int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
+int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
+
+
+/*-----------------------------------------------------------------
+ * Functions for manipulating device-mapper tables.
+ *---------------------------------------------------------------*/
+
+/*
+ * First create an empty table.
+ */
+int dm_table_create(struct dm_table **result, int mode,
+		    unsigned num_targets, struct mapped_device *md);
+
+/*
+ * Then call this once for each target.
+ */
+int dm_table_add_target(struct dm_table *t, const char *type,
+			sector_t start, sector_t len, char *params);
+
+/*
+ * Finally call this to make the table ready for use.
+ */
+int dm_table_complete(struct dm_table *t);
+
+/*
+ * Table reference counting.
+ */
+struct dm_table *dm_get_table(struct mapped_device *md);
+void dm_table_get(struct dm_table *t);
+void dm_table_put(struct dm_table *t);
+
+/*
+ * Queries
+ */
+sector_t dm_table_get_size(struct dm_table *t);
+unsigned int dm_table_get_num_targets(struct dm_table *t);
+int dm_table_get_mode(struct dm_table *t);
+struct mapped_device *dm_table_get_md(struct dm_table *t);
+
+/*
+ * Trigger an event.
+ */
+void dm_table_event(struct dm_table *t);
+
+/*
+ * The device must be suspended before calling this method.
+ */
+int dm_swap_table(struct mapped_device *md, struct dm_table *t);
+
+#endif	/* __KERNEL__ */
+#endif	/* _LINUX_DEVICE_MAPPER_H */