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From: Ming Lei <ming.lei@redhat.com>
To: John Garry <john.garry@huawei.com>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	kashyap.desai@broadcom.com, hare@suse.de
Subject: Re: [PATCH 1/9] blk-mq: Change rqs check in blk_mq_free_rqs()
Date: Tue, 20 Jul 2021 15:35:48 +0800	[thread overview]
Message-ID: <YPZ81HsYnyxBpQwu@T590> (raw)
In-Reply-To: <1626275195-215652-2-git-send-email-john.garry@huawei.com>

On Wed, Jul 14, 2021 at 11:06:27PM +0800, John Garry wrote:
> The original code in commit 24d2f90309b23 ("blk-mq: split out tag
> initialization, support shared tags") would check tags->rqs is non-NULL and
> then dereference tags->rqs[].
> 
> Then in commit 2af8cbe30531 ("blk-mq: split tag ->rqs[] into two"), we
> started to dereference tags->static_rqs[], but continued to check non-NULL
> tags->rqs.
> 
> Check tags->static_rqs as non-NULL instead, which is more logical.
> 
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
>  block/blk-mq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 2c4ac51e54eb..ae28f470893c 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2348,7 +2348,7 @@ void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
>  {
>  	struct page *page;
>  
> -	if (tags->rqs && set->ops->exit_request) {
> +	if (tags->static_rqs && set->ops->exit_request) {

Yeah, it is reasonable to check ->static_rqs since both ->init_request()
and ->exit_request() operate on request from ->static_rqs[]:

Reviewed-by: Ming Lei <ming.lei@redhat.com>

-- 
Ming


  reply	other threads:[~2021-07-20  7:36 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14 15:06 [PATCH 0/9] blk-mq: Reduce static requests memory footprint for shared sbitmap John Garry
2021-07-14 15:06 ` [PATCH 1/9] blk-mq: Change rqs check in blk_mq_free_rqs() John Garry
2021-07-20  7:35   ` Ming Lei [this message]
2021-07-14 15:06 ` [PATCH 2/9] block: Rename BLKDEV_MAX_RQ -> BLKDEV_DEFAULT_RQ John Garry
2021-07-20  7:44   ` Ming Lei
2021-07-14 15:06 ` [PATCH 3/9] blk-mq: Relocate shared sbitmap resize in blk_mq_update_nr_requests() John Garry
2021-07-20  7:50   ` Ming Lei
2021-07-20  8:06     ` John Garry
2021-07-14 15:06 ` [PATCH 4/9] blk-mq: Add blk_mq_tag_resize_sched_shared_sbitmap() John Garry
2021-07-20  7:57   ` Ming Lei
2021-07-20  8:08     ` John Garry
2021-07-14 15:06 ` [PATCH 5/9] blk-mq: Invert check in blk_mq_update_nr_requests() John Garry
2021-07-14 15:06 ` [PATCH RFC 6/9] blk-mq: Refactor blk_mq_{alloc,free}_rqs John Garry
2021-07-14 15:06 ` [PATCH RFC 7/9] blk-mq: Allocate per tag set static rqs for shared sbitmap John Garry
2021-07-14 15:06 ` [PATCH 8/9] blk-mq: Allocate per request queue " John Garry
2021-07-14 15:06 ` [PATCH 9/9] blk-mq: Clear mappings for shared sbitmap sched static rqs John Garry
2021-07-20 15:22 ` [PATCH 0/9] blk-mq: Reduce static requests memory footprint for shared sbitmap Ming Lei
2021-07-20 17:05   ` John Garry

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