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| author |   Jiri Kosina <jkosina@suse.cz> | 2012-08-27 08:04:24 -0700 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2012-08-27 08:05:17 -0700 |
| commit | 66a61fc0b2c3475f26f65b5f29ed5945b8efbf9e (patch) | |
| tree | 28ebaaee56786cd9199e0e5802d166474d30d1e3 /fs/btrfs/locking.c | |
| parent | HID: hid-debug: Show rdesc for unclaimed devices (diff) | |
| parent | Merge branch 'upstream-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid (diff) | |
| download | wireguard-linux-66a61fc0b2c3475f26f65b5f29ed5945b8efbf9e.tar.xz wireguard-linux-66a61fc0b2c3475f26f65b5f29ed5945b8efbf9e.zip | |
Merge branch 'master' into upstream
Sync with Linus' tree so that we don't have build falures
due to Quanta 3001 ID reshuffling.
Diffstat (limited to 'fs/btrfs/locking.c')
| -rw-r--r-- | fs/btrfs/locking.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index 272f911203ff..a44eff074805 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -78,13 +78,15 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw) write_lock(&eb->lock); WARN_ON(atomic_read(&eb->spinning_writers)); atomic_inc(&eb->spinning_writers); - if (atomic_dec_and_test(&eb->blocking_writers)) + if (atomic_dec_and_test(&eb->blocking_writers) && + waitqueue_active(&eb->write_lock_wq)) wake_up(&eb->write_lock_wq); } else if (rw == BTRFS_READ_LOCK_BLOCKING) { BUG_ON(atomic_read(&eb->blocking_readers) == 0); read_lock(&eb->lock); atomic_inc(&eb->spinning_readers); - if (atomic_dec_and_test(&eb->blocking_readers)) + if (atomic_dec_and_test(&eb->blocking_readers) && + waitqueue_active(&eb->read_lock_wq)) wake_up(&eb->read_lock_wq); } return; @@ -199,7 +201,8 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb) } btrfs_assert_tree_read_locked(eb); WARN_ON(atomic_read(&eb->blocking_readers) == 0); - if (atomic_dec_and_test(&eb->blocking_readers)) + if (atomic_dec_and_test(&eb->blocking_readers) && + waitqueue_active(&eb->read_lock_wq)) wake_up(&eb->read_lock_wq); atomic_dec(&eb->read_locks); } @@ -247,8 +250,9 @@ void btrfs_tree_unlock(struct extent_buffer *eb) if (blockers) { WARN_ON(atomic_read(&eb->spinning_writers)); atomic_dec(&eb->blocking_writers); - smp_wmb(); - wake_up(&eb->write_lock_wq); + smp_mb(); + if (waitqueue_active(&eb->write_lock_wq)) + wake_up(&eb->write_lock_wq); } else { WARN_ON(atomic_read(&eb->spinning_writers) != 1); atomic_dec(&eb->spinning_writers); |