blk-mq: use switch/case to improve readability in blk_mq_try_issue_list_directly

Use switch/case handle error as other function do to improve
readability in blk_mq_try_issue_list_directly.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -2802,18 +2802,22 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
 
 		list_del_init(&rq->queuelist);
 		ret = blk_mq_request_issue_directly(rq, list_empty(list));
-		if (ret != BLK_STS_OK) {
-			if (ret == BLK_STS_RESOURCE ||
-					ret == BLK_STS_DEV_RESOURCE) {
+		switch (ret) {
+		case BLK_STS_OK:
+			queued++;
+			break;
+		case BLK_STS_RESOURCE:
+		case BLK_STS_DEV_RESOURCE:
 			blk_mq_request_bypass_insert(rq, false,
 						     list_empty(list));
+			goto out;
+		default:
+			blk_mq_end_request(rq, ret);
 			break;
 		}
-			blk_mq_end_request(rq, ret);
-		} else
-			queued++;
 	}
 
+out:
 	if (ret != BLK_STS_OK)
 		blk_mq_commit_rqs(hctx, queued, false);
 }