virtio-blk: use a helper to handle request queuing errors

Define a new helper function, virtblk_fail_to_queue(), to
clean up the error handling code in virtio_queue_rq().
Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Message-Id: <20221016034127.330942-2-dmitry.fomichev@wdc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/block/virtio_blk.c

@@ -315,6 +315,19 @@ static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
 		virtqueue_notify(vq->vq);
 }
 
+static blk_status_t virtblk_fail_to_queue(struct request *req, int rc)
+{
+	virtblk_cleanup_cmd(req);
+	switch (rc) {
+	case -ENOSPC:
+		return BLK_STS_DEV_RESOURCE;
+	case -ENOMEM:
+		return BLK_STS_RESOURCE;
+	default:
+		return BLK_STS_IOERR;
+	}
+}
+
 static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx,
 					struct virtio_blk *vblk,
 					struct request *req,
@@ -327,10 +340,8 @@ static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx,
 		return status;
 
 	vbr->sg_table.nents = virtblk_map_data(hctx, req, vbr);
-	if (unlikely(vbr->sg_table.nents < 0)) {
-		virtblk_cleanup_cmd(req);
-		return BLK_STS_RESOURCE;
-	}
+	if (unlikely(vbr->sg_table.nents < 0))
+		return virtblk_fail_to_queue(req, -ENOMEM);
 
 	blk_mq_start_request(req);
 
@@ -364,15 +375,7 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 			blk_mq_stop_hw_queue(hctx);
 		spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
 		virtblk_unmap_data(req, vbr);
-		virtblk_cleanup_cmd(req);
-		switch (err) {
-		case -ENOSPC:
-			return BLK_STS_DEV_RESOURCE;
-		case -ENOMEM:
-			return BLK_STS_RESOURCE;
-		default:
-			return BLK_STS_IOERR;
-		}
+		return virtblk_fail_to_queue(req, err);
 	}
 
 	if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))