linux-kernel - Re: [PATCH v2] gpu: drm/amd: Remove the redundant null pointer check in list_for_each

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]

Message-ID: <19a8be24-0b5c-4232-d3ba-dc7f269bafd3@amd.com>
Date:   Mon, 12 Jun 2023 11:25:20 -0400
From:   Felix Kuehling <felix.kuehling@....com>
To:     Lu Hongfei <luhongfei@...o.com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        "open list:AMD KFD" <amd-gfx@...ts.freedesktop.org>,
        "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>,
        "Kim, Jonathan" <Jonathan.Kim@....com>
Cc:     opensource.kernel@...o.com
Subject: Re: [PATCH v2] gpu: drm/amd: Remove the redundant null pointer check
 in list_for_each_entry() loops

[+Jon]

Am 2023-06-12 um 07:58 schrieb Lu Hongfei:
> pqn bound in list_for_each_entry loop will not be null, so there is
> no need to check whether pqn is NULL or not.
> Thus remove a redundant null pointer check.
>
> Signed-off-by: Lu Hongfei <luhongfei@...o.com>
> ---
> The filename of the previous version was:
> 0001-gpu-drm-amd-Fix-the-bug-in-list_for_each_entry-loops.patch
>
> The modifications made compared to the previous version are as follows:
> 1. Modified the patch title
> 2. "Thus remove a redundant null pointer check." is used instead of
>     "We could remove this check."
>
>   drivers/gpu/drm/amd/amdkfd/kfd_debug.c | 3 ---
>   1 file changed, 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_debug.c b/drivers/gpu/drm/amd/amdkfd/kfd_debug.c
> index cd34e7aaead4..10d0cef844f0 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_debug.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_debug.c
> @@ -1097,9 +1097,6 @@ void kfd_dbg_set_enabled_debug_exception_mask(struct kfd_process *target,
>   
>   	pqm = &target->pqm;
>   	list_for_each_entry(pqn, &pqm->queues, process_queue_list) {
> -		if (!pqn)

Right, this check doesn't make a lot of sense. Jon, was this meant to 
check pqn->q?

Regards,
   Felix


> -			continue;
> -
>   		found_mask |= pqn->q->properties.exception_status;
>   	}
>