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tty: make the kref destructor occur asynchronously

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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 <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Cox 2009-09-19 13:13:22 -07:00 committed by Live-CD User
parent e936ffd5cb
commit b50989dc44
1 changed files with 16 additions and 3 deletions
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19
drivers/char/tty_io.c
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@ -1386,10 +1386,14 @@ EXPORT_SYMBOL(tty_shutdown);
* tty_mutex - sometimes only * tty_mutex - sometimes only
* takes the file list lock internally when working on the list * takes the file list lock internally when working on the list
* of ttys that the driver keeps. * 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; struct tty_driver *driver = tty->driver;
if (tty->ops->shutdown) if (tty->ops->shutdown)
@ -1407,6 +1411,15 @@ static void release_one_tty(struct kref *kref)
free_tty_struct(tty); 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_kref_put - release a tty kref
* @tty: tty device * @tty: tty device
@ -1418,7 +1431,7 @@ static void release_one_tty(struct kref *kref)
void tty_kref_put(struct tty_struct *tty) void tty_kref_put(struct tty_struct *tty)
{ {
if (tty) if (tty)
kref_put(&tty->kref, release_one_tty); kref_put(&tty->kref, queue_release_one_tty);
} }
EXPORT_SYMBOL(tty_kref_put); EXPORT_SYMBOL(tty_kref_put);