Mutex unlock implies certain memory barriers to make sure all the memory operation completes before the unlock, and the next mutex lock implies memory barriers to make sure the all the memory happens after the lock. So it is a full memory barrier(smp_mb), we needn't add memory barriers. Remove them. Signed-off-by: Miao Xie <miaox@xxxxxxxxxxxxxx> --- fs/btrfs/tree-log.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 51d1bd9..c9f2479 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -2497,7 +2497,6 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, root->log_transid++; log->log_transid = root->log_transid; root->log_start_pid = 0; - smp_mb(); /* * IO has been started, blocks of the log tree have WRITTEN flag set * in their headers. new modifications of the log will be written to @@ -2590,8 +2589,6 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, btrfs_header_level(log_root_tree->node)); log_root_tree->log_transid++; - smp_mb(); - mutex_unlock(&log_root_tree->log_mutex); /* -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
