btrfs: remove extra barrier before waitqueue_active
Removing barriers is scary, but a call to atomic_dec_and_test implies
a barrier, so we don't need to issue another one.
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index d0deb46..6327559 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -229,7 +229,9 @@
void btrfs_end_log_trans(struct btrfs_root *root)
{
if (atomic_dec_and_test(&root->log_writers)) {
- smp_mb();
+ /*
+ * Implicit memory barrier after atomic_dec_and_test
+ */
if (waitqueue_active(&root->log_writer_wait))
wake_up(&root->log_writer_wait);
}
@@ -2820,7 +2822,9 @@
mutex_lock(&log_root_tree->log_mutex);
if (atomic_dec_and_test(&log_root_tree->log_writers)) {
- smp_mb();
+ /*
+ * Implicit memory barrier after atomic_dec_and_test
+ */
if (waitqueue_active(&log_root_tree->log_writer_wait))
wake_up(&log_root_tree->log_writer_wait);
}