linux-kernel - Re: [PATCH] drm/amdgpu/userq: remove unnecessary NULL check

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Message-ID: <8409b02a-811a-4bf6-a4a0-2eb63778a79c@amd.com>
Date: Wed, 30 Apr 2025 14:35:01 +0200
From: Christian König <christian.koenig@....com>
To: "Sharma, Shashank" <Shashank.Sharma@....com>,
 Dan Carpenter <dan.carpenter@...aro.org>,
 "Deucher, Alexander" <Alexander.Deucher@....com>
Cc: David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 "Khatri, Sunil" <Sunil.Khatri@....com>, "Yadav, Arvind"
 <Arvind.Yadav@....com>,
 "Paneer Selvam, Arunpravin" <Arunpravin.PaneerSelvam@....com>,
 "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
 "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: Re: [PATCH] drm/amdgpu/userq: remove unnecessary NULL check

On 4/30/25 11:28, Sharma, Shashank wrote:
> [AMD Official Use Only - AMD Internal Distribution Only]
> 
> 
> Hello Dan,
> 
> --------------------------------------------------------------------------------
> *From:* Dan Carpenter
> *Sent:* Wednesday, April 30, 2025 10:05 AM
> *To:* Deucher, Alexander
> *Cc:* Koenig, Christian; David Airlie; Simona Vetter; Sharma, Shashank; Khatri, 
> Sunil; Yadav, Arvind; Paneer Selvam, Arunpravin; amd-gfx@...ts.freedesktop.org; 
> dri-devel@...ts.freedesktop.org; linux-kernel@...r.kernel.org; kernel- 
> janitors@...r.kernel.org
> *Subject:* [PATCH] drm/amdgpu/userq: remove unnecessary NULL check
> 
> The "ticket" pointer points to in the middle of the &exec struct so it
> can't be NULL.  Remove the check.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/ 
> amdgpu/amdgpu_userq.c
> index b0e8098a3988..7505d920fb3d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> @@ -631,7 +631,7 @@ amdgpu_userq_validate_bos(struct amdgpu_userq_mgr *uq_mgr)
>                           clear = false;
>                           unlock = true;
>                   /* The caller is already holding the reservation lock */
> -               } else if (ticket && dma_resv_locking_ctx(resv) == ticket) {
> +               } else if (dma_resv_locking_ctx(resv) == ticket) {
> 
> Its a Nack for me, There are a few situations (particularly during the first 
> launch of the desktop, and also when eviction fence and new queue creation are 
> working in parallel) where this ticket can be NULL, we observed it during the 
> stress validation and hence added this check,

What that maybe before the code was moved around?

As far as I can see the ticket can't be NULL any more.

Regards,
Christian.


> 
> Regards,
> Shashank
> 
> 
>                           clear = false;
>                           unlock = false;
>                   /* Somebody else is using the BO right now */
> --
> 2.47.2
>