btrfs: reada: Move is_need_to_readahead contition earlier
Move is_need_to_readahead contition earlier to avoid useless loop
to get relative data for readahead.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index f0cf5f3..b2f768a 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -660,7 +660,6 @@
u64 logical;
int ret;
int i;
- int need_kick = 0;
spin_lock(&fs_info->reada_lock);
if (dev->reada_curr_zone == NULL) {
@@ -696,6 +695,15 @@
spin_unlock(&fs_info->reada_lock);
+ spin_lock(&re->lock);
+ if (re->scheduled_for || list_empty(&re->extctl)) {
+ spin_unlock(&re->lock);
+ reada_extent_put(fs_info, re);
+ return 0;
+ }
+ re->scheduled_for = dev;
+ spin_unlock(&re->lock);
+
/*
* find mirror num
*/
@@ -707,18 +715,8 @@
}
logical = re->logical;
- spin_lock(&re->lock);
- if (!re->scheduled_for && !list_empty(&re->extctl)) {
- re->scheduled_for = dev;
- need_kick = 1;
- }
- spin_unlock(&re->lock);
-
reada_extent_put(fs_info, re);
- if (!need_kick)
- return 0;
-
atomic_inc(&dev->reada_in_flight);
ret = reada_tree_block_flagged(fs_info->extent_root, logical,
mirror_num, &eb);