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authorMiao Xie <miaox@cn.fujitsu.com>2014-02-20 18:08:55 +0800
committerJosef Bacik <jbacik@fb.com>2014-03-10 15:16:41 -0400
commit7483e1a4464999c72b231af0efe39cb31fd73f14 (patch)
treea9e5db4bb0cdd568002b735aa795109e9f9d4f32
parente87ac1368700af66c295afa47e5c7df0d9d8b919 (diff)
downloadlinux-7483e1a4464999c72b231af0efe39cb31fd73f14.tar.bz2
Btrfs: remove unnecessary memory barrier in btrfs_sync_log()
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@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com>
-rw-r--r--fs/btrfs/tree-log.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index ca960ad271fe..285c168391f3 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2496,7 +2496,6 @@ 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
@@ -2589,8 +2588,6 @@ 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);
/*