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Commit b50989dc authored by Alan Cox's avatar Alan Cox Committed by Live-CD User
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tty: make the kref destructor occur asynchronously 



We want to be able to sleep in the destructor for USB at least. It isn't a
hot path so just pushing it to a work queue doesn't really cause any
difficulty.

Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent e936ffd5

drivers/char/tty_io.c

+16 −3
Original line number Diff line number Diff line
@@ -1386,10 +1386,14 @@ EXPORT_SYMBOL(tty_shutdown); 
 *		tty_mutex - sometimes only

 *		takes the file list lock internally when working on the list

 *	of ttys that the driver keeps.

 *

 *	This method gets called from a work queue so that the driver private

 *	shutdown ops can sleep (needed for USB at least)

 */

static void release_one_tty(struct kref *kref)

static void release_one_tty(struct work_struct *work)

{

	struct tty_struct *tty = container_of(kref, struct tty_struct, kref);

	struct tty_struct *tty =

		container_of(work, struct tty_struct, hangup_work);

	struct tty_driver *driver = tty->driver;



	if (tty->ops->shutdown)
@@ -1407,6 +1411,15 @@ static void release_one_tty(struct kref *kref) 
	free_tty_struct(tty);

}



static void queue_release_one_tty(struct kref *kref)

{

	struct tty_struct *tty = container_of(kref, struct tty_struct, kref);

	/* The hangup queue is now free so we can reuse it rather than

	   waste a chunk of memory for each port */

	INIT_WORK(&tty->hangup_work, release_one_tty);

	schedule_work(&tty->hangup_work);

}



/**

 *	tty_kref_put		-	release a tty kref

 *	@tty: tty device
@@ -1418,7 +1431,7 @@ static void release_one_tty(struct kref *kref) 
void tty_kref_put(struct tty_struct *tty)

{

	if (tty)

		kref_put(&tty->kref, release_one_tty);

		kref_put(&tty->kref, queue_release_one_tty);

}

EXPORT_SYMBOL(tty_kref_put);