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authorDavid Sterba <dsterba@suse.com>2015-02-16 19:39:00 +0100
committerDavid Sterba <dsterba@suse.com>2015-10-10 18:40:33 +0200
commit779adf0f647651f5a45eeee3442c881300ce989e (patch)
tree4f9e555faf8ce150305cea076a31d509653205bb /fs/btrfs/tree-log.c
parenta83342aa0c8f0ca90057d3837ae8d198186e5153 (diff)
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>
Diffstat (limited to 'fs/btrfs/tree-log.c')
-rw-r--r--fs/btrfs/tree-log.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index d0deb4643502..63275594debd 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -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);
}