linux-kernel - [PATCH] blk-mq: use struct

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Message-ID: <20251018213831.260055-1-mehdi.benhadjkhelifa@gmail.com>
Date: Sat, 18 Oct 2025 22:38:13 +0100
From: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
To: axboe@...nel.dk
Cc: linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	skhan@...uxfoundation.org,
	david.hunter.linux@...il.com,
	khalid@...nel.org,
	linux-kernel-mentees@...ts.linuxfoundation.org,
	Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
Subject: [PATCH] blk-mq: use struct_size() in kmalloc()

Change struct size calculation to use struct_size()
to align with new recommended practices[1] which quotes:
"Another common case to avoid is calculating the size of a structure with
a trailing array of others structures, as in:

header = kzalloc(sizeof(*header) + count * sizeof(*header->item),
                 GFP_KERNEL);

Instead, use the helper:

header = kzalloc(struct_size(header, item, count), GFP_KERNEL);"

Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
---
 block/blk-mq-sched.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index e0bed16485c3..97b69fbe26f6 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -466,8 +466,7 @@ struct elevator_tags *blk_mq_alloc_sched_tags(struct blk_mq_tag_set *set,
 	else
 		nr_tags = nr_hw_queues;
 
-	et = kmalloc(sizeof(struct elevator_tags) +
-			nr_tags * sizeof(struct blk_mq_tags *), gfp);
+	et = kmalloc(struct_size(et, tags, nr_tags), gfp);
 	if (!et)
 		return NULL;
 
-- 
2.51.1.dirty