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Subject: Re: [PATCH] drm/amdgpu: remove unreachable code
To:     Jiapeng Chong <jiapeng.chong@linux.alibaba.com>,
        alexander.deucher@amd.com
Cc:     airlied@linux.ie, daniel@ffwll.ch, sumit.semwal@linaro.org,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
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References: <1621853213-55876-1-git-send-email-jiapeng.chong@linux.alibaba.com>
From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
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Am 24.05.21 um 12:46 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.

Mhm, that is a NAK. IIRC we explicitely added that code because some 
compiler versions complained that we don't return a value at the end of 
the function.

I suggest to drop the return from the default case and the BUG() instead.

Regards,
Christian.

>
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c | 2 --
>   1 file changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> index 82f0542..375b346 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> @@ -842,8 +842,6 @@ static int amdgpu_uvd_cs_msg(struct amdgpu_uvd_cs_ctx *ctx,
>   		DRM_ERROR("Illegal UVD message type (%d)!\n", msg_type);
>   		return -EINVAL;
>   	}
> -	BUG();
> -	return -EINVAL;
>   }
>   
>   /**