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Subject: Re: [PATCH v2] amdgpu: remove unreachable code
To:     Jiapeng Chong <jiapeng.chong@linux.alibaba.com>,
        alexander.deucher@amd.com
Cc:     airlied@linux.ie, Xinhui.Pan@amd.com, linux-kernel@vger.kernel.org,
        amd-gfx@lists.freedesktop.org, sumit.semwal@linaro.org,
        linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org,
        daniel@ffwll.ch, christian.koenig@amd.com,
        linux-media@vger.kernel.org
References: <1621939214-57004-1-git-send-email-jiapeng.chong@linux.alibaba.com>
From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <ckoenig.leichtzumerken@gmail.com>
Message-ID: <0dbdc879-8da7-3a08-1e42-6b8b88dfceb6@gmail.com>
Date:   Tue, 25 May 2021 16:09:12 +0200
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Am 25.05.21 um 12:40 schrieb Jiapeng Chong:
> In the function amdgpu_uvd_cs_msg(), every branch in the switch
> statement will have a return, so the code below the switch statement
> will not be executed.
>
> Eliminate the follow smatch warning:
>
> drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c:845 amdgpu_uvd_cs_msg() warn:
> ignoring unreachable code.
>
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> ---
> Changes in v2:
>    -For the follow advice: https://lore.kernel.org/patchwork/patch/1435074/
>
>   drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c | 1 -
>   1 file changed, 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> index 82f0542..b32ed85 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> @@ -840,7 +840,6 @@ static int amdgpu_uvd_cs_msg(struct amdgpu_uvd_cs_ctx *ctx,
>   
>   	default:
>   		DRM_ERROR("Illegal UVD message type (%d)!\n", msg_type);
> -		return -EINVAL;
>   	}
>   	BUG();

You also need to remove the BUG() here or otherwise that will crash on 
an relatively harmless error.

Christian.

>   	return -EINVAL;