linux-kernel - [PATCH v2] block/mq-deadline: Remove redundant hctx pointer dereferencing operation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251118012539.61711-1-pilgrimtao@gmail.com>
Date: Tue, 18 Nov 2025 09:25:39 +0800
From: chengkaitao <pilgrimtao@...il.com>
To: axboe@...nel.dk
Cc: linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Chengkaitao <chengkaitao@...inos.cn>
Subject: [PATCH v2] block/mq-deadline: Remove redundant hctx pointer dereferencing operation

From: Chengkaitao <chengkaitao@...inos.cn>

The value of 'hctx->queue' is already stored in '*q' within
dd_insert_requests, we can directly reuse the result instead of
dereferencing hctx again in the dd_insert_request function. This
patch removes the redundant operation and modifies the function's
parameters accordingly. We can eliminate an LDR instruction.

Signed-off-by: Chengkaitao <chengkaitao@...inos.cn>
---
v2:
  1. Remove the changes related to bfq-iosched.
  2. Add more commit message.
v1:
  https://lore.kernel.org/all/20251016131651.83182-1-pilgrimtao@gmail.com/
---
 block/mq-deadline.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 3e741d33142d..5007d811a738 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -633,10 +633,9 @@ static bool dd_bio_merge(struct request_queue *q, struct bio *bio,
 /*
  * add rq to rbtree and fifo
  */
-static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
+static void dd_insert_request(struct request_queue *q, struct request *rq,
 			      blk_insert_t flags, struct list_head *free)
 {
-	struct request_queue *q = hctx->queue;
 	struct deadline_data *dd = q->elevator->elevator_data;
 	const enum dd_data_dir data_dir = rq_data_dir(rq);
 	u16 ioprio = req_get_ioprio(rq);
@@ -694,7 +693,7 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
 
 		rq = list_first_entry(list, struct request, queuelist);
 		list_del_init(&rq->queuelist);
-		dd_insert_request(hctx, rq, flags, &free);
+		dd_insert_request(q, rq, flags, &free);
 	}
 	spin_unlock(&dd->lock);
 
-- 
2.50.1 (Apple Git-155)