xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

btrfs: comment the rest of implicit barriers before waitqueue_active

Browse Source 
There are atomic operations that imply the barrier for waitqueue_active
mixed in an if-condition.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba
2015-02-16 19:41:40 +01:00
parent 779adf0f64
commit ee86395458
5 changed files with 22 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
fs/btrfs/locking.c
View File

@@ -79,6 +79,9 @@ 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);
/*
* atomic_dec_and_test implies a barrier for waitqueue_active
*/
if (atomic_dec_and_test(&eb->blocking_writers) &&
waitqueue_active(&eb->write_lock_wq))
wake_up(&eb->write_lock_wq);
@@ -86,6 +89,9 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw)
BUG_ON(atomic_read(&eb->blocking_readers) == 0);
read_lock(&eb->lock);
atomic_inc(&eb->spinning_readers);
/*
* atomic_dec_and_test implies a barrier for waitqueue_active
*/
if (atomic_dec_and_test(&eb->blocking_readers) &&
waitqueue_active(&eb->read_lock_wq))
wake_up(&eb->read_lock_wq);
@@ -229,6 +235,9 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
}
btrfs_assert_tree_read_locked(eb);
WARN_ON(atomic_read(&eb->blocking_readers) == 0);
/*
* atomic_dec_and_test implies a barrier for waitqueue_active
*/
if (atomic_dec_and_test(&eb->blocking_readers) &&
waitqueue_active(&eb->read_lock_wq))
wake_up(&eb->read_lock_wq);