Commit 779adf0f authored by David Sterba's avatar David Sterba
Browse files

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: default avatarDavid Sterba <dsterba@suse.com>
parent a83342aa

fs/btrfs/tree-log.c

+6 −2
Original line number Diff line number Diff line
@@ -229,7 +229,9 @@ int btrfs_pin_log_trans(struct btrfs_root *root) 
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 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, 


	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);

	}