virtio_blk: correct types for status handling

virtblk_setup_cmd returns blk_status_t in an int, callers then assign it
back to a blk_status_t variable. blk_status_t is either u32 or (more
typically) u8 so it works, but is inelegant and causes sparse warnings.

Pass the status in blk_status_t in a consistent way.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: b2c5221fd074 ("virtio-blk: avoid preallocating big SGL for data")
Cc: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

drivers/block/virtio_blk.c

@@ -208,8 +208,9 @@ static void virtblk_cleanup_cmd(struct request *req)
 		kfree(bvec_virt(&req->special_vec));
 }
 
-static int virtblk_setup_cmd(struct virtio_device *vdev, struct request *req,
-		struct virtblk_req *vbr)
+static blk_status_t virtblk_setup_cmd(struct virtio_device *vdev,
+				      struct request *req,
+				      struct virtblk_req *vbr)
 {
 	bool unmap = false;
 	u32 type;
@@ -317,14 +318,15 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 	unsigned long flags;
 	unsigned int num;
 	int qid = hctx->queue_num;
-	int err;
 	bool notify = false;
+	blk_status_t status;
+	int err;
 
 	BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
 
-	err = virtblk_setup_cmd(vblk->vdev, req, vbr);
-	if (unlikely(err))
-		return err;
+	status = virtblk_setup_cmd(vblk->vdev, req, vbr);
+	if (unlikely(status))
+		return status;
 
 	blk_mq_start_request(req);