linux-kernel - [PATCH 05/15] block: req->bio is always set in the merge code

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Message-ID: <20241119121632.1225556-6-hch@lst.de>
Date: Tue, 19 Nov 2024 13:16:19 +0100
From: Christoph Hellwig <hch@....de>
To: Jens Axboe <axboe@...nel.dk>
Cc: Christian Brauner <brauner@...nel.org>,
	Keith Busch <kbusch@...nel.org>,
	Sagi Grimberg <sagi@...mberg.me>,
	Kanchan Joshi <joshi.k@...sung.com>,
	Hui Qi <hui81.qi@...sung.com>,
	Nitesh Shetty <nj.shetty@...sung.com>,
	Jan Kara <jack@...e.cz>,
	Pavel Begunkov <asml.silence@...il.com>,
	linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-nvme@...ts.infradead.org,
	linux-fsdevel@...r.kernel.org,
	io-uring@...r.kernel.org,
	Dan Carpenter <dan.carpenter@...aro.org>
Subject: [PATCH 05/15] block: req->bio is always set in the merge code

As smatch, which is a lot smarter than me noticed.  So remove the checks
for it, and condense these checks a bit including the comments stating
the obvious.

Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Signed-off-by: Christoph Hellwig <hch@....de>
---
 block/blk-merge.c | 30 ++++++++----------------------
 1 file changed, 8 insertions(+), 22 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 64860cbd5e27..e01383c6e534 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -864,14 +864,10 @@ static struct request *attempt_merge(struct request_queue *q,
 	if (req_op(req) != req_op(next))
 		return NULL;
 
-	if (req->bio && next->bio) {
-		/* Don't merge requests with different write hints. */
-		if (req->bio->bi_write_hint != next->bio->bi_write_hint)
-			return NULL;
-		if (req->bio->bi_ioprio != next->bio->bi_ioprio)
-			return NULL;
-	}
-
+	if (req->bio->bi_write_hint != next->bio->bi_write_hint)
+		return NULL;
+	if (req->bio->bi_ioprio != next->bio->bi_ioprio)
+		return NULL;
 	if (!blk_atomic_write_mergeable_rqs(req, next))
 		return NULL;
 
@@ -983,26 +979,16 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 	if (req_op(rq) != bio_op(bio))
 		return false;
 
-	/* don't merge across cgroup boundaries */
 	if (!blk_cgroup_mergeable(rq, bio))
 		return false;
-
-	/* only merge integrity protected bio into ditto rq */
 	if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
 		return false;
-
-	/* Only merge if the crypt contexts are compatible */
 	if (!bio_crypt_rq_ctx_compatible(rq, bio))
 		return false;
-
-	if (rq->bio) {
-		/* Don't merge requests with different write hints. */
-		if (rq->bio->bi_write_hint != bio->bi_write_hint)
-			return false;
-		if (rq->bio->bi_ioprio != bio->bi_ioprio)
-			return false;
-	}
-
+	if (rq->bio->bi_write_hint != bio->bi_write_hint)
+		return false;
+	if (rq->bio->bi_ioprio != bio->bi_ioprio)
+		return false;
 	if (blk_atomic_write_mergeable_rq_bio(rq, bio) == false)
 		return false;
 
-- 
2.45.2