Re: [PATCH 2/8] loop: remove always true check

[Christoph Hellwig <hch@xxxxxx>]

lo_complete_rq is still a complete mess.  I'd suggest something like
this instead:

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 8f140d6374356..1648d30a8cb4a 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -517,40 +517,37 @@ static void lo_flush_dcache_for_read(struct request *rq)
 static void lo_complete_rq(struct request *rq)
 {
 	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
-	blk_status_t ret = BLK_STS_OK;
+
+	if (cmd->ret < 0) {
+		blk_mq_end_request(rq, errno_to_blk_status(cmd->ret));
+		return;
+	}
 
 	/* Kernel wrote to our pages, call flush_dcache_page */
 	if (req_op(rq) == REQ_OP_READ && !cmd->use_aio && cmd->ret >= 0)
 		lo_flush_dcache_for_read(rq);
 
-	if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) ||
-	    req_op(rq) != REQ_OP_READ) {
-		if (cmd->ret < 0)
-			ret = errno_to_blk_status(cmd->ret);
-		goto end_io;
-	}
-
 	/*
-	 * Short READ - if we got some data, advance our request and
-	 * retry it. If we got no data, end the rest with EIO.
+	 * Short READ - if we got some data, advance our request and retry it.
+	 * If we got no data, end the rest with EIO.
 	 */
-	if (cmd->ret) {
-		blk_update_request(rq, BLK_STS_OK, cmd->ret);
-		cmd->ret = 0;
-		blk_mq_requeue_request(rq, true);
-	} else {
-		if (cmd->use_aio) {
-			struct bio *bio = rq->bio;
+	if (req_op(rq) == REQ_OP_READ && cmd->use_aio &&
+	    cmd->ret != blk_rq_bytes(rq)) {
+		if (cmd->ret) {
+			blk_update_request(rq, BLK_STS_OK, cmd->ret);
+			cmd->ret = 0;
+			blk_mq_requeue_request(rq, true);
+		} else {
+			struct bio *bio;
 
-			while (bio) {
+			for (bio = rq->bio; bio; bio = bio->bi_next)
 				zero_fill_bio(bio);
-				bio = bio->bi_next;
-			}
+			blk_mq_end_request(rq, BLK_STS_IOERR);
 		}
-		ret = BLK_STS_IOERR;
-end_io:
-		blk_mq_end_request(rq, ret);
+		return;
 	}
+
+	blk_mq_end_request(rq, BLK_STS_OK);
 }
 
 static void lo_rw_aio_do_completion(struct loop_cmd *cmd)