linux-kernel - Re: [PATCH RESEND v3 08/13] blk-mq: Don't clear driver tags own mapping

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

Date:   Tue, 14 Sep 2021 07:45:50 +0200
From:   Hannes Reinecke <hare@...e.de>
To:     John Garry <john.garry@...wei.com>, axboe@...nel.dk
Cc:     linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        ming.lei@...hat.com, linux-scsi@...r.kernel.org
Subject: Re: [PATCH RESEND v3 08/13] blk-mq: Don't clear driver tags own
 mapping

On 9/13/21 5:12 PM, John Garry wrote:
> Function blk_mq_clear_rq_mapping() is required to clear the sched tags
> mappings in driver tags rqs[].
> 
> But there is no need for a driver tags to clear its own mapping, so skip
> clearing the mapping in this scenario.
> 
> Signed-off-by: John Garry <john.garry@...wei.com>
> ---
>   block/blk-mq.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 4bae8afdfbe1..5229c5420b85 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2308,6 +2308,10 @@ static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
>   	struct page *page;
>   	unsigned long flags;
>   
> +	/* There is no need to clear a driver tags own mapping */
> +	if (drv_tags == tags)
> +		return;
> +
>   	list_for_each_entry(page, &tags->page_list, lru) {
>   		unsigned long start = (unsigned long)page_address(page);
>   		unsigned long end = start + order_to_size(page->private);
> 
Reviewed-by: Hannes Reinecke <hare@...e.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@...e.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer