btrfs: merge find_free_dev_extent() and find_free_dev_extent_start()

There is no point in having find_free_dev_extent() because it's just a
simple wrapper around find_free_dev_extent_start() which always passes a
value of 0 for the search_start argument. Since there are no other callers
of find_free_dev_extent_start(), remove find_free_dev_extent() and rename
find_free_dev_extent_start() to find_free_dev_extent(), removing its
search_start argument because it's always 0.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -1439,18 +1439,18 @@ static bool contains_pending_extent(struct btrfs_device *device, u64 *start,
 	return false;
 }
 
-static u64 dev_extent_search_start(struct btrfs_device *device, u64 start)
+static u64 dev_extent_search_start(struct btrfs_device *device)
 {
 	switch (device->fs_devices->chunk_alloc_policy) {
 	case BTRFS_CHUNK_ALLOC_REGULAR:
-		return max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED);
+		return BTRFS_DEVICE_RANGE_RESERVED;
 	case BTRFS_CHUNK_ALLOC_ZONED:
 		/*
 		 * We don't care about the starting region like regular
 		 * allocator, because we anyway use/reserve the first two zones
 		 * for superblock logging.
 		 */
-		return ALIGN(start, device->zone_info->zone_size);
+		return 0;
 	default:
 		BUG();
 	}
@@ -1582,15 +1582,15 @@ static bool dev_extent_hole_check(struct btrfs_device *device, u64 *hole_start,
  * correct usable device space, as device extent freed in current transaction
  * is not reported as available.
  */
-static int find_free_dev_extent_start(struct btrfs_device *device,
-				u64 num_bytes, u64 search_start, u64 *start,
-				u64 *len)
+static int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
+				u64 *start, u64 *len)
 {
 	struct btrfs_fs_info *fs_info = device->fs_info;
 	struct btrfs_root *root = fs_info->dev_root;
 	struct btrfs_key key;
 	struct btrfs_dev_extent *dev_extent;
 	struct btrfs_path *path;
+	u64 search_start;
 	u64 hole_size;
 	u64 max_hole_start;
 	u64 max_hole_size;
@@ -1600,7 +1600,7 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
 	int slot;
 	struct extent_buffer *l;
 
-	search_start = dev_extent_search_start(device, search_start);
+	search_start = dev_extent_search_start(device);
 
 	WARN_ON(device->zone_info &&
 		!IS_ALIGNED(num_bytes, device->zone_info->zone_size));
@@ -1726,13 +1726,6 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
 	return ret;
 }
 
-static int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
-				u64 *start, u64 *len)
-{
-	/* FIXME use last free of some kind */
-	return find_free_dev_extent_start(device, num_bytes, 0, start, len);
-}
-
 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 			  struct btrfs_device *device,
 			  u64 start, u64 *dev_extent_len)