linux-kernel - Re: [PATCH] drm/amdgpu/fence: Remove redundant 0 value initialization

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Message-ID: <00e7ce33-cc0a-4249-ac18-081ab9ead243@amd.com>
Date: Tue, 19 Aug 2025 10:41:37 +0200
From: Christian König <christian.koenig@....com>
To: Liao Yuanhong <liaoyuanhong@...o.com>,
 Alex Deucher <alexander.deucher@....com>, David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>, Thomas Gleixner <tglx@...utronix.de>,
 Ingo Molnar <mingo@...nel.org>,
 Srinivasan Shanmugam <srinivasan.shanmugam@....com>,
 Lijo Lazar <lijo.lazar@....com>,
 "open list:RADEON and AMDGPU DRM DRIVERS" <amd-gfx@...ts.freedesktop.org>,
 "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
 open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/amdgpu/fence: Remove redundant 0 value initialization

On 19.08.25 10:25, Liao Yuanhong wrote:
> The amdgpu_fence struct is already zeroed by kzalloc(). It's redundant to
> initialize am_fence->context to 0.
> 
> Signed-off-by: Liao Yuanhong <liaoyuanhong@...o.com>

Reviewed-by: Christian König <christian.koenig@....com>

If you want a challenge what we would really use is a scan of all the structures defined in drivers/gpu/drm/amd/amdgpu/*.[ch] for unused fields.

The UAPI and BIOS/HW header files are full of padding fields, but there shouldn't be any in the driver core defines and we sometimes forget to remove fields from structures when they are not used any more.

Regards,
Christian.

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> index bcb74286a78a..fd8cca241da6 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> @@ -120,7 +120,6 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f,
>  		am_fence = kzalloc(sizeof(*am_fence), GFP_KERNEL);
>  		if (!am_fence)
>  			return -ENOMEM;
> -		am_fence->context = 0;
>  	} else {
>  		am_fence = af;
>  	}