btrfs: update btrfs_add_block_group_cache() to use rb helper

Update fs/btrfs/block-group.c to use rb_find_add_cached().

Suggested-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Roger L. Beckermeyer III <beckerlee3@gmail.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 5be029734cfa2cdc576b44281667a72a5f107d40..39881d66cfa064c5b66f61d4a60d84cd8458cd81 100644 (file)
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -173,43 +173,41 @@ void btrfs_put_block_group(struct btrfs_block_group *cache)
        }
 }
 
+static int btrfs_bg_start_cmp(const struct rb_node *new,
+                             const struct rb_node *exist)
+{
+       const struct btrfs_block_group *new_bg =
+               rb_entry(new, struct btrfs_block_group, cache_node);
+       const struct btrfs_block_group *exist_bg =
+               rb_entry(exist, struct btrfs_block_group, cache_node);
+
+       if (new_bg->start < exist_bg->start)
+               return -1;
+       if (new_bg->start > exist_bg->start)
+               return 1;
+       return 0;
+}
+
 /*
  * This adds the block group to the fs_info rb tree for the block group cache
  */
 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
                                       struct btrfs_block_group *block_group)
 {
-       struct rb_node **p;
-       struct rb_node *parent = NULL;
-       struct btrfs_block_group *cache;
-       bool leftmost = true;
+       struct rb_node *exist;
+       int ret = 0;
 
        ASSERT(block_group->length != 0);
 
        write_lock(&info->block_group_cache_lock);
-       p = &info->block_group_cache_tree.rb_root.rb_node;
-
-       while (*p) {
-               parent = *p;
-               cache = rb_entry(parent, struct btrfs_block_group, cache_node);
-               if (block_group->start < cache->start) {
-                       p = &(*p)->rb_left;
-               } else if (block_group->start > cache->start) {
-                       p = &(*p)->rb_right;
-                       leftmost = false;
-               } else {
-                       write_unlock(&info->block_group_cache_lock);
-                       return -EEXIST;
-               }
-       }
-
-       rb_link_node(&block_group->cache_node, parent, p);
-       rb_insert_color_cached(&block_group->cache_node,
-                              &info->block_group_cache_tree, leftmost);
 
+       exist = rb_find_add_cached(&block_group->cache_node,
+                       &info->block_group_cache_tree, btrfs_bg_start_cmp);
+       if (exist)
+               ret = -EEXIST;
        write_unlock(&info->block_group_cache_lock);
 
-       return 0;
+       return ret;
 }
 
 /*