From b50989dc444599c8b21edc23536fc305f4e9b7d5 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Sat, 19 Sep 2009 13:13:22 -0700 Subject: [PATCH] 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: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/char/tty_io.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 938448067738..385cca7074da 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -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);