2015-06-29 04:34:04

by Maninder Singh

Subject: [RFC][PATCH 1/1] drm/amdkfd: Remove redundant pdd validation

pdd is already dereferenced before this check.
So it is redundtant to validate pdd here.

Signed-off-by: Maninder Singh <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_process.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 8a1f999..4dbc4e5 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -431,8 +431,7 @@ void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
* We don't call amd_iommu_unbind_pasid() here
* because the IOMMU called us.
*/
- if (pdd)
- pdd->bound = false;
+ pdd->bound = false;

mutex_unlock(&p->mutex);
}
--
1.7.9.5

2015-07-09 08:48:07

by Oded Gabbay

Subject: Re: [RFC][PATCH 1/1] drm/amdkfd: Remove redundant pdd validation

On Mon, Jun 29, 2015 at 7:33 AM, Maninder Singh <[email protected]> wrote:
>
> pdd is already dereferenced before this check.
> So it is redundtant to validate pdd here.
>
> Signed-off-by: Maninder Singh <[email protected]>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_process.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index 8a1f999..4dbc4e5 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -431,8 +431,7 @@ void kfd_unbind_process_from_device(struct kfd_dev *dev, unsigned int pasid)
> * We don't call amd_iommu_unbind_pasid() here
> * because the IOMMU called us.
> */
> - if (pdd)
> - pdd->bound = false;
> + pdd->bound = false;
>
> mutex_unlock(&p->mutex);
> }
> --
> 1.7.9.5
>
Hi Maninder,

You are correct pdd was already dereferenced so this check is
redundant. However, I think a better patch would be to move the check
to where pdd is first acquired (a few lines above it), because I don't
see there any check.

Could you please do that and resend the patch ? Use latest v4.2-rc1
label from Linus please.

Thansk,

Oded