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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-20 21:28:04 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-20 21:28:04 -0800
commite4286926abbbaab9b047c8bc25cae78ec990928f (patch)
tree02d3c80e581476d93253df5c16dbf9f907494e1c /drivers/tty/tty_io.c
parent3342ff2698e9720f4040cc458a2744b2b32f5c3a (diff)
parenta157270fbf37f822e1fa9e9faa8ed8c81da1eb28 (diff)
Merge tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver updates from Greg KH: "Here is the big set of tty/serial driver changes for 5.12-rc1. Nothing huge, just lots of good cleanups and additions: - n_tty line discipline cleanups - vt core cleanups and reworks to make the code more "modern" - stm32 driver additions - tty led support added to the tty core and led layer - minor serial driver fixups and additions All of these have been in linux-next for a while with no reported issues" * tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (54 commits) serial: core: Remove BUG_ON(in_interrupt()) check vt_ioctl: Remove in_interrupt() check dt-bindings: serial: imx: Switch to my personal address vt: keyboard, use new API for keyboard_tasklet serial: stm32: improve platform_get_irq condition handling in init_port serial: ifx6x60: Remove driver for deprecated platform tty: fix up iterate_tty_read() EOVERFLOW handling tty: fix up hung_up_tty_read() conversion tty: fix up hung_up_tty_write() conversion tty: teach the n_tty ICANON case about the new "cookie continuations" too tty: teach n_tty line discipline about the new "cookie continuations" tty: clean up legacy leftovers from n_tty line discipline tty: implement read_iter tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer serial: remove sirf prima/atlas driver serial: mxs-auart: Remove <asm/cacheflush.h> serial: mxs-auart: Remove serial_mxs_probe_dt() serial: fsl_lpuart: Use of_device_get_match_data() dt-bindings: serial: renesas,hscif: Add r8a779a0 support tty: serial: Drop unused efm32 serial driver ...
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r--drivers/tty/tty_io.c210
1 files changed, 167 insertions, 43 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 082da38762fc..74733ec8f565 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -142,7 +142,7 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */
/* Mutex to protect creating and releasing a tty */
DEFINE_MUTEX(tty_mutex);
-static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
+static ssize_t tty_read(struct kiocb *, struct iov_iter *);
static ssize_t tty_write(struct kiocb *, struct iov_iter *);
static __poll_t tty_poll(struct file *, poll_table *);
static int tty_open(struct inode *, struct file *);
@@ -429,8 +429,7 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line)
EXPORT_SYMBOL_GPL(tty_find_polling_driver);
#endif
-static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
- size_t count, loff_t *ppos)
+static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to)
{
return 0;
}
@@ -473,8 +472,9 @@ static void tty_show_fdinfo(struct seq_file *m, struct file *file)
static const struct file_operations tty_fops = {
.llseek = no_llseek,
- .read = tty_read,
+ .read_iter = tty_read,
.write_iter = tty_write,
+ .splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.poll = tty_poll,
.unlocked_ioctl = tty_ioctl,
@@ -487,8 +487,9 @@ static const struct file_operations tty_fops = {
static const struct file_operations console_fops = {
.llseek = no_llseek,
- .read = tty_read,
+ .read_iter = tty_read,
.write_iter = redirected_tty_write,
+ .splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.poll = tty_poll,
.unlocked_ioctl = tty_ioctl,
@@ -500,7 +501,7 @@ static const struct file_operations console_fops = {
static const struct file_operations hung_up_tty_fops = {
.llseek = no_llseek,
- .read = hung_up_tty_read,
+ .read_iter = hung_up_tty_read,
.write_iter = hung_up_tty_write,
.poll = hung_up_tty_poll,
.unlocked_ioctl = hung_up_tty_ioctl,
@@ -539,6 +540,29 @@ void tty_wakeup(struct tty_struct *tty)
EXPORT_SYMBOL_GPL(tty_wakeup);
/**
+ * tty_release_redirect - Release a redirect on a pty if present
+ * @tty: tty device
+ *
+ * This is available to the pty code so if the master closes, if the
+ * slave is a redirect it can release the redirect. It returns the
+ * filp for the redirect, which must be fput when the operations on
+ * the tty are completed.
+ */
+struct file *tty_release_redirect(struct tty_struct *tty)
+{
+ struct file *f = NULL;
+
+ spin_lock(&redirect_lock);
+ if (redirect && file_tty(redirect) == tty) {
+ f = redirect;
+ redirect = NULL;
+ }
+ spin_unlock(&redirect_lock);
+
+ return f;
+}
+
+/**
* __tty_hangup - actual handler for hangup events
* @tty: tty device
* @exit_session: if non-zero, signal all foreground group processes
@@ -564,7 +588,7 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
static void __tty_hangup(struct tty_struct *tty, int exit_session)
{
struct file *cons_filp = NULL;
- struct file *filp, *f = NULL;
+ struct file *filp, *f;
struct tty_file_private *priv;
int closecount = 0, n;
int refs;
@@ -572,13 +596,7 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
if (!tty)
return;
-
- spin_lock(&redirect_lock);
- if (redirect && file_tty(redirect) == tty) {
- f = redirect;
- redirect = NULL;
- }
- spin_unlock(&redirect_lock);
+ f = tty_release_redirect(tty);
tty_lock(tty);
@@ -829,6 +847,72 @@ static void tty_update_time(struct timespec64 *time)
time->tv_sec = sec;
}
+/*
+ * Iterate on the ldisc ->read() function until we've gotten all
+ * the data the ldisc has for us.
+ *
+ * The "cookie" is something that the ldisc read function can fill
+ * in to let us know that there is more data to be had.
+ *
+ * We promise to continue to call the ldisc until it stops returning
+ * data or clears the cookie. The cookie may be something that the
+ * ldisc maintains state for and needs to free.
+ */
+static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
+ struct file *file, struct iov_iter *to)
+{
+ int retval = 0;
+ void *cookie = NULL;
+ unsigned long offset = 0;
+ char kernel_buf[64];
+ size_t count = iov_iter_count(to);
+
+ do {
+ int size, copied;
+
+ size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
+ size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
+ if (!size)
+ break;
+
+ if (size < 0) {
+ /* Did we have an earlier error (ie -EFAULT)? */
+ if (retval)
+ break;
+ retval = size;
+
+ /*
+ * -EOVERFLOW means we didn't have enough space
+ * for a whole packet, and we shouldn't return
+ * a partial result.
+ */
+ if (retval == -EOVERFLOW)
+ offset = 0;
+ break;
+ }
+
+ copied = copy_to_iter(kernel_buf, size, to);
+ offset += copied;
+ count -= copied;
+
+ /*
+ * If the user copy failed, we still need to do another ->read()
+ * call if we had a cookie to let the ldisc clear up.
+ *
+ * But make sure size is zeroed.
+ */
+ if (unlikely(copied != size)) {
+ count = 0;
+ retval = -EFAULT;
+ }
+ } while (cookie);
+
+ /* We always clear tty buffer in case they contained passwords */
+ memzero_explicit(kernel_buf, sizeof(kernel_buf));
+ return offset ? offset : retval;
+}
+
+
/**
* tty_read - read method for tty device files
* @file: pointer to tty file
@@ -844,10 +928,10 @@ static void tty_update_time(struct timespec64 *time)
* read calls may be outstanding in parallel.
*/
-static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
- loff_t *ppos)
+static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
{
int i;
+ struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct tty_struct *tty = file_tty(file);
struct tty_ldisc *ld;
@@ -861,11 +945,10 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
situation */
ld = tty_ldisc_ref_wait(tty);
if (!ld)
- return hung_up_tty_read(file, buf, count, ppos);
+ return hung_up_tty_read(iocb, to);
+ i = -EIO;
if (ld->ops->read)
- i = ld->ops->read(tty, file, buf, count);
- else
- i = -EIO;
+ i = iterate_tty_read(ld, tty, file, to);
tty_ldisc_deref(ld);
if (i > 0)
@@ -1889,22 +1972,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
return driver;
}
-/**
- * tty_kopen - open a tty device for kernel
- * @device: dev_t of device to open
- *
- * Opens tty exclusively for kernel. Performs the driver lookup,
- * makes sure it's not already opened and performs the first-time
- * tty initialization.
- *
- * Returns the locked initialized &tty_struct
- *
- * Claims the global tty_mutex to serialize:
- * - concurrent first-time tty initialization
- * - concurrent tty driver removal w/ lookup
- * - concurrent tty removal from driver table
- */
-struct tty_struct *tty_kopen(dev_t device)
+static struct tty_struct *tty_kopen(dev_t device, int shared)
{
struct tty_struct *tty;
struct tty_driver *driver;
@@ -1919,7 +1987,7 @@ struct tty_struct *tty_kopen(dev_t device)
/* check whether we're reopening an existing tty */
tty = tty_driver_lookup_tty(driver, NULL, index);
- if (IS_ERR(tty))
+ if (IS_ERR(tty) || shared)
goto out;
if (tty) {
@@ -1937,7 +2005,42 @@ out:
tty_driver_kref_put(driver);
return tty;
}
-EXPORT_SYMBOL_GPL(tty_kopen);
+
+/**
+ * tty_kopen_exclusive - open a tty device for kernel
+ * @device: dev_t of device to open
+ *
+ * Opens tty exclusively for kernel. Performs the driver lookup,
+ * makes sure it's not already opened and performs the first-time
+ * tty initialization.
+ *
+ * Returns the locked initialized &tty_struct
+ *
+ * Claims the global tty_mutex to serialize:
+ * - concurrent first-time tty initialization
+ * - concurrent tty driver removal w/ lookup
+ * - concurrent tty removal from driver table
+ */
+struct tty_struct *tty_kopen_exclusive(dev_t device)
+{
+ return tty_kopen(device, 0);
+}
+EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
+
+/**
+ * tty_kopen_shared - open a tty device for shared in-kernel use
+ * @device: dev_t of device to open
+ *
+ * Opens an already existing tty for in-kernel use. Compared to
+ * tty_kopen_exclusive() above it doesn't ensure to be the only user.
+ *
+ * Locking is identical to tty_kopen() above.
+ */
+struct tty_struct *tty_kopen_shared(dev_t device)
+{
+ return tty_kopen(device, 1);
+}
+EXPORT_SYMBOL_GPL(tty_kopen_shared);
/**
* tty_open_by_driver - open a tty device
@@ -2488,15 +2591,36 @@ static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
return tty->ops->tiocmset(tty, set, clear);
}
+/**
+ * tty_get_icount - get tty statistics
+ * @tty: tty device
+ * @icount: output parameter
+ *
+ * Gets a copy of the tty's icount statistics.
+ *
+ * Locking: none (up to the driver)
+ */
+int tty_get_icount(struct tty_struct *tty,
+ struct serial_icounter_struct *icount)
+{
+ memset(icount, 0, sizeof(*icount));
+
+ if (tty->ops->get_icount)
+ return tty->ops->get_icount(tty, icount);
+ else
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(tty_get_icount);
+
static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
{
- int retval = -EINVAL;
struct serial_icounter_struct icount;
- memset(&icount, 0, sizeof(icount));
- if (tty->ops->get_icount)
- retval = tty->ops->get_icount(tty, &icount);
+ int retval;
+
+ retval = tty_get_icount(tty, &icount);
if (retval != 0)
return retval;
+
if (copy_to_user(arg, &icount, sizeof(icount)))
return -EFAULT;
return 0;
@@ -2887,7 +3011,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
static int this_tty(const void *t, struct file *file, unsigned fd)
{
- if (likely(file->f_op->read != tty_read))
+ if (likely(file->f_op->read_iter != tty_read))
return 0;
return file_tty(file) != t ? 0 : fd + 1;
}