Commit 0bfd464d authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
Browse files

tty: Wait interruptibly for tty lock on reopen 



Allow a signal to interrupt the wait for a tty reopen; eg., if
the tty has starting final close and is waiting for the device to
drain.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org> # 4.4
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 92e963f5

drivers/tty/tty_io.c

+7 −1
Original line number Diff line number Diff line
@@ -2065,7 +2065,12 @@ retry_open: 


		if (tty) {

			mutex_unlock(&tty_mutex);

			tty_lock(tty);

			retval = tty_lock_interruptible(tty);

			if (retval) {

				if (retval == -EINTR)

					retval = -ERESTARTSYS;

				goto err_unref;

			}

			/* safe to drop the kref from tty_driver_lookup_tty() */

			tty_kref_put(tty);

			retval = tty_reopen(tty);
@@ -2152,6 +2157,7 @@ retry_open: 
	return 0;

err_unlock:

	mutex_unlock(&tty_mutex);

err_unref:

	/* after locks to avoid deadlock */

	if (!IS_ERR_OR_NULL(driver))

		tty_driver_kref_put(driver);

drivers/tty/tty_mutex.c

+8 −0
Original line number Diff line number Diff line
@@ -19,6 +19,14 @@ void __lockfunc tty_lock(struct tty_struct *tty) 
}

EXPORT_SYMBOL(tty_lock);



int tty_lock_interruptible(struct tty_struct *tty)

{

	if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))

		return -EIO;

	tty_kref_get(tty);

	return mutex_lock_interruptible(&tty->legacy_mutex);

}



void __lockfunc tty_unlock(struct tty_struct *tty)

{

	if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty))

include/linux/tty.h

+1 −0
Original line number Diff line number Diff line
@@ -649,6 +649,7 @@ extern long vt_compat_ioctl(struct tty_struct *tty, 
/* tty_mutex.c */

/* functions for preparation of BKL removal */

extern void __lockfunc tty_lock(struct tty_struct *tty);

extern int  tty_lock_interruptible(struct tty_struct *tty);

extern void __lockfunc tty_unlock(struct tty_struct *tty);

extern void __lockfunc tty_lock_slave(struct tty_struct *tty);

extern void __lockfunc tty_unlock_slave(struct tty_struct *tty);

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