mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
fuse: fix blocked_waitq wakeup
Using waitqueue_active() is racy. Make sure we issue a wake_up()
unconditionally after storing into fc->blocked. After that it's okay to
optimize with waitqueue_active() since the first wake up provides the
necessary barrier for all waiters, not the just the woken one.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 3c18ef8117
("fuse: optimize wake_up")
Cc: <stable@vger.kernel.org> # v3.10
This commit is contained in:
parent
4c316f2f3f
commit
908a572b80
1 changed files with 11 additions and 4 deletions
|
@ -391,12 +391,19 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
|
|||
if (test_bit(FR_BACKGROUND, &req->flags)) {
|
||||
spin_lock(&fc->lock);
|
||||
clear_bit(FR_BACKGROUND, &req->flags);
|
||||
if (fc->num_background == fc->max_background)
|
||||
if (fc->num_background == fc->max_background) {
|
||||
fc->blocked = 0;
|
||||
|
||||
/* Wake up next waiter, if any */
|
||||
if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
|
||||
wake_up(&fc->blocked_waitq);
|
||||
} else if (!fc->blocked) {
|
||||
/*
|
||||
* Wake up next waiter, if any. It's okay to use
|
||||
* waitqueue_active(), as we've already synced up
|
||||
* fc->blocked with waiters with the wake_up() call
|
||||
* above.
|
||||
*/
|
||||
if (waitqueue_active(&fc->blocked_waitq))
|
||||
wake_up(&fc->blocked_waitq);
|
||||
}
|
||||
|
||||
if (fc->num_background == fc->congestion_threshold && fc->sb) {
|
||||
clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
|
||||
|
|
Loading…
Reference in a new issue