[PATCH] drm/amdgpu: address the static checker warnings

[Quan, Evan]

-----Original Message-----
From: Dan Carpenter <dan.carpenter at oracle.com> 
Sent: Friday, April 24, 2020 7:02 PM
To: Quan, Evan <Evan.Quan at amd.com>
Cc: amd-gfx at lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher at amd.com>
Subject: Re: [PATCH] drm/amdgpu: address the static checker warnings

On Fri, Apr 24, 2020 at 06:41:15PM +0800, Evan Quan wrote:
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:4199 amdgpu_device_gpu_recover()
> error: we previously assumed 'hive' could be null (see line 4196)
> 
> This is introduced by "drm/amdgpu: optimize the gpu reset for XGMI setup V2".
> 
> Change-Id: I9c22b57abc9f512114112f93fb035f1fecf26beb
> Signed-off-by: Evan Quan <evan.quan at amd.com>
> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 71278942f9f0..898338dc9605 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -4274,7 +4274,8 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
>  		if (!amdgpu_device_lock_adev(tmp_adev, !hive)) {
>  			DRM_INFO("Bailing on TDR for s_job:%llx, as another already in progress",
>  				  job ? job->base.id : -1);
> -			mutex_unlock(&hive->hive_lock);
> +			if (hive)
> +				mutex_unlock(&hive->hive_lock);

In the current code, we know for a fact that "hive" is NULL at this
point. 
[Evan] No, that's true for SGPU setup only. For XGMI setup(multiple dgpus interconnected with bridges), the "hive" here is not NULL.
Presumably this will be changed in the future?  Otherwise why
not just delete the mutex_unlock() because it is dead code.

regards,
dan carpenter