[PATCH v2 2/2] btrfs: Use list_for_each_entry_safe in free_reloc_roots

[Nikolay Borisov <nborisov@suse.com>]

The function always works on a local copy of the reloc root list, which
cannot be modified outside of it so using list_for_each_entry is fine.
Additionally the macro handles empty lists so drop list_empty checks of
callers. No semantic changes.
---

V2: Base the patch on current misc-next rather than on a branch with Josef's
subvol cleanups part 2. 

 fs/btrfs/relocation.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 4b8c80de925b..a8898894f443 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2523,11 +2523,9 @@ int prepare_to_merge(struct reloc_control *rc, int err)
 static noinline_for_stack
 void free_reloc_roots(struct list_head *list)
 {
-	struct btrfs_root *reloc_root;
+	struct btrfs_root *reloc_root, *tmp;
 
-	while (!list_empty(list)) {
-		reloc_root = list_entry(list->next, struct btrfs_root,
-					root_list);
+	list_for_each_entry_safe(reloc_root, tmp, list, root_list) {
 		__del_reloc_root(reloc_root);
 		free_extent_buffer(reloc_root->node);
 		free_extent_buffer(reloc_root->commit_root);
@@ -2592,15 +2590,13 @@ void merge_reloc_roots(struct reloc_control *rc)
 out:
 	if (ret) {
 		btrfs_handle_fs_error(fs_info, ret, NULL);
-		if (!list_empty(&reloc_roots))
-			free_reloc_roots(&reloc_roots);
+		free_reloc_roots(&reloc_roots);
 
 		/* new reloc root may be added */
 		mutex_lock(&fs_info->reloc_mutex);
 		list_splice_init(&rc->reloc_roots, &reloc_roots);
 		mutex_unlock(&fs_info->reloc_mutex);
-		if (!list_empty(&reloc_roots))
-			free_reloc_roots(&reloc_roots);
+		free_reloc_roots(&reloc_roots);
 	}
 
 	BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
@@ -4693,8 +4689,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
 out_free:
 	kfree(rc);
 out:
-	if (!list_empty(&reloc_roots))
-		free_reloc_roots(&reloc_roots);
+	free_reloc_roots(&reloc_roots);
 
 	btrfs_free_path(path);
 
-- 
2.17.1