[v2,2/3] btrfs: BTRFS_PATH_AUTO_FREE in zoned.c

Commit Message

Leo Martins Aug. 27, 2024, 7:08 p.m. UTC

Add automatic path freeing in zoned.c, the examples here are both fairly
trivial with one exit path and the only cleanup is btrfs_free_path.
---
 fs/btrfs/zoned.c | 34 +++++++++++-----------------------
 1 file changed, 11 insertions(+), 23 deletions(-)

Comments

David Sterba Aug. 28, 2024, 12:23 a.m. UTC | #1

On Tue, Aug 27, 2024 at 12:08:44PM -0700, Leo Martins wrote:
> Add automatic path freeing in zoned.c, the examples here are both fairly
> trivial with one exit path and the only cleanup is btrfs_free_path.
> ---
>  fs/btrfs/zoned.c | 34 +++++++++++-----------------------
>  1 file changed, 11 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index 66f63e82af793..158bb0b708805 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -287,7 +287,7 @@ static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos,
>  /* The emulated zone size is determined from the size of device extent */
>  static int calculate_emulated_zone_size(struct btrfs_fs_info *fs_info)
>  {
> -	struct btrfs_path *path;
> +	BTRFS_PATH_AUTO_FREE(path);

This looks good, I've tested that applied in the code and looked at the
function how it feels in the code, I think we can settle on that.

So if you're going to send more such updates, you can use a template
changelog like:

"All cleanup paths lead to btrfs_path_free so we can define path with the
 automatic free callback."

It describes why it can be used and roughly what it does if somebody
sees it for the first time.

Patch

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 66f63e82af793..158bb0b708805 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -287,7 +287,7 @@  static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos,
 /* The emulated zone size is determined from the size of device extent */
 static int calculate_emulated_zone_size(struct btrfs_fs_info *fs_info)
 {
-	struct btrfs_path *path;
+	BTRFS_PATH_AUTO_FREE(path);
 	struct btrfs_root *root = fs_info->dev_root;
 	struct btrfs_key key;
 	struct extent_buffer *leaf;
@@ -304,28 +304,21 @@  static int calculate_emulated_zone_size(struct btrfs_fs_info *fs_info)
 
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	if (ret < 0)
-		goto out;
+		return ret;
 
 	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
 		ret = btrfs_next_leaf(root, path);
 		if (ret < 0)
-			goto out;
+			return ret;
 		/* No dev extents at all? Not good */
-		if (ret > 0) {
-			ret = -EUCLEAN;
-			goto out;
-		}
+		if (ret > 0)
+			return -EUCLEAN;
 	}
 
 	leaf = path->nodes[0];
 	dext = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent);
 	fs_info->zone_size = btrfs_dev_extent_length(leaf, dext);
-	ret = 0;
-
-out:
-	btrfs_free_path(path);
-
-	return ret;
+	return 0;
 }
 
 int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info)
@@ -1211,7 +1204,7 @@  static int calculate_alloc_pointer(struct btrfs_block_group *cache,
 {
 	struct btrfs_fs_info *fs_info = cache->fs_info;
 	struct btrfs_root *root;
-	struct btrfs_path *path;
+	BTRFS_PATH_AUTO_FREE(path);
 	struct btrfs_key key;
 	struct btrfs_key found_key;
 	int ret;
@@ -1246,7 +1239,7 @@  static int calculate_alloc_pointer(struct btrfs_block_group *cache,
 	if (!ret)
 		ret = -EUCLEAN;
 	if (ret < 0)
-		goto out;
+		return ret;
 
 	ret = btrfs_previous_extent_item(root, path, cache->start);
 	if (ret) {
@@ -1254,7 +1247,7 @@  static int calculate_alloc_pointer(struct btrfs_block_group *cache,
 			ret = 0;
 			*offset_ret = 0;
 		}
-		goto out;
+		return ret;
 	}
 
 	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
@@ -1266,15 +1259,10 @@  static int calculate_alloc_pointer(struct btrfs_block_group *cache,
 
 	if (!(found_key.objectid >= cache->start &&
 	       found_key.objectid + length <= cache->start + cache->length)) {
-		ret = -EUCLEAN;
-		goto out;
+		return -EUCLEAN;
 	}
 	*offset_ret = found_key.objectid + length - cache->start;
-	ret = 0;
-
-out:
-	btrfs_free_path(path);
-	return ret;
+	return 0;
 }
 
 struct zone_info {