diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 49a02bf091ae..204d585e012a 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1863,7 +1863,7 @@ restore:
 }
 
 /* Used to sort the devices by max_avail(descending sort) */
-static int btrfs_cmp_device_free_bytes(const void *dev_info1,
+static inline int btrfs_cmp_device_free_bytes(const void *dev_info1,
 				       const void *dev_info2)
 {
 	if (((struct btrfs_device_info *)dev_info1)->max_avail >
@@ -1892,8 +1892,8 @@ static inline void btrfs_descending_sort_devices(
  * The helper to calc the free space on the devices that can be used to store
  * file data.
  */
-static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
-				       u64 *free_bytes)
+static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
+					      u64 *free_bytes)
 {
 	struct btrfs_device_info *devices_info;
 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;