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

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

[Evan Quan]

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@amd.com>
Reported-by: Dan Carpenter <dan.carpenter@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);
 			return 0;
 		}
 
-- 
2.26.2

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

[Dan Carpenter]

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@amd.com>
> Reported-by: Dan Carpenter <dan.carpenter@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.  Presumably this will be changed in the future?  Otherwise why
not just delete the mutex_unlock() because it is dead code.

regards,
dan carpenter

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

[Quan, Evan]

-----Original Message-----
From: Dan Carpenter <dan.carpenter@oracle.com> 
Sent: Friday, April 24, 2020 7:02 PM
To: Quan, Evan <Evan.Quan@amd.com>
Cc: amd-gfx@lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher@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@amd.com>
> Reported-by: Dan Carpenter <dan.carpenter@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

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

[Quan, Evan]

Ping..

-----Original Message-----
From: Quan, Evan 
Sent: Sunday, April 26, 2020 11:19 AM
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: amd-gfx@lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher@amd.com>
Subject: RE: [PATCH] drm/amdgpu: address the static checker warnings



-----Original Message-----
From: Dan Carpenter <dan.carpenter@oracle.com>
Sent: Friday, April 24, 2020 7:02 PM
To: Quan, Evan <Evan.Quan@amd.com>
Cc: amd-gfx@lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher@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@amd.com>
> Reported-by: Dan Carpenter <dan.carpenter@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

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

[Dan Carpenter]

On Tue, Apr 28, 2020 at 02:31:12AM +0000, Quan, Evan wrote:
> Ping..

Are you asking me?  It's really hard for me to read your emails.
Normally email clients put "> " in front of the quoted parts of the
email.  Your email client doesn't line wrap at 72 characters either.  :(

> [Evan] No, that's true for SGPU setup only. For XGMI setup(multiple dgpus interconnected with bridges), the "hive" here is not NULL.

Presumably you are talking about out of tree code so I can't comment
on this.  In the current linux-next we know that amdgpu_device_lock_adev()
will only return false when "hive" is NULL.

regards,
dan carpenter

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

[Quan, Evan]

Thanks, I think I get your point. With hive!= NULL, it never fails on the amdgpu_device_lock_adev().
Sorry for miss that. Will send a new patch.

Regards,
Evan
-----Original Message-----
From: Dan Carpenter <dan.carpenter@oracle.com> 
Sent: Tuesday, April 28, 2020 7:02 PM
To: Quan, Evan <Evan.Quan@amd.com>
Cc: amd-gfx@lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher@amd.com>
Subject: Re: [PATCH] drm/amdgpu: address the static checker warnings

On Tue, Apr 28, 2020 at 02:31:12AM +0000, Quan, Evan wrote:
> Ping..

Are you asking me?  It's really hard for me to read your emails.
Normally email clients put "> " in front of the quoted parts of the email.  Your email client doesn't line wrap at 72 characters either.  :(

> [Evan] No, that's true for SGPU setup only. For XGMI setup(multiple dgpus interconnected with bridges), the "hive" here is not NULL.

Presumably you are talking about out of tree code so I can't comment on this.  In the current linux-next we know that amdgpu_device_lock_adev() will only return false when "hive" is NULL.

regards,
dan carpenter

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