loop: do not print warn message if partition scan is successful

Do not print warn message when the partition scan returns 0.

Fixes: d57f3374ba ("loop: Move special partition reread handling in loop_clr_fd()")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/loop.c

@@ -1115,8 +1115,9 @@ out_unlock:
 			err = __blkdev_reread_part(bdev);
 		else
 			err = blkdev_reread_part(bdev);
-		pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
-			__func__, lo_number, err);
+		if (err)
+			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
+				__func__, lo_number, err);
 		/* Device is gone, no point in returning error */
 		err = 0;
 	}