btrfs: make find_free_dev_extent() static

The function find_free_dev_extent() is only used within volumes.c, so make
it static and remove its prototype from volumes.h.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -1726,8 +1726,8 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
 	return ret;
 }
 
-int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
-			 u64 *start, u64 *len)
+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);

fs/btrfs/volumes.h

@@ -650,8 +650,6 @@ int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
 int btrfs_uuid_scan_kthread(void *data);
 bool btrfs_chunk_writeable(struct btrfs_fs_info *fs_info, u64 chunk_offset);
-int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
-			 u64 *start, u64 *max_avail);
 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index);
 int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
 			struct btrfs_ioctl_get_dev_stats *stats);