md: add __acquires/__releases annotations to handle_active_stripes

This tells sparse that we release and reacquire the device_lock and
avoids a warning.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d794d87..2b0a715 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6159,6 +6159,8 @@ static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
 static int handle_active_stripes(struct r5conf *conf, int group,
 				 struct r5worker *worker,
 				 struct list_head *temp_inactive_list)
+		__releases(&conf->device_lock)
+		__acquires(&conf->device_lock)
 {
 	struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
 	int i, batch_size = 0, hash;