linux-kernel - Re: [PATCH] drm/amd/amdkfd: Drop unnecessary NULL check after container

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Date:   Fri, 21 May 2021 18:08:59 -0400
From:   Felix Kuehling <felix.kuehling@....com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/amd/amdkfd: Drop unnecessary NULL check after
 container_of

Am 2021-05-21 um 11:02 a.m. schrieb Guenter Roeck:
> The first parameter passed to container_of() is the pointer to the work
> structure passed to the worker and never NULL. The NULL check on the
> result of container_of() is therefore unnecessary and misleading.
> Remove it.
>
> This change was made automatically with the following Coccinelle script.
>
> @@
> type t;
> identifier v;
> statement s;
> @@
>
> <+...
> (
>   t v = container_of(...);
> |
>   v = container_of(...);
> )
>   ...
>   when != v
> - if (\( !v \| v == NULL \) ) s
> ...+>
>
> Signed-off-by: Guenter Roeck <linux@...ck-us.net>

Thank you. The patch looks good to me. I caught a few such pointless
checks in code review but must have missed this one. I'll apply your
patch to amd-staging-drm-next. The patch is

Reviewed-by: Felix Kuehling <Felix.Kuehling@....com>


> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_process.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index 5b6c5669c03d..2f8d352e0069 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -110,8 +110,6 @@ static void kfd_sdma_activity_worker(struct work_struct *work)
>  
>  	workarea = container_of(work, struct kfd_sdma_activity_handler_workarea,
>  				sdma_activity_work);
> -	if (!workarea)
> -		return;
>  
>  	pdd = workarea->pdd;
>  	if (!pdd)