Re: [PATCH] amdgpu/uvd: use kmemdup

From: "Christian König" <christian.koenig@amd.com>
To: Muhammad Falak R Wani <falakreyaz@gmail.com>,
	David Airlie <airlied@linux.ie>
Cc: Jammy Zhou <Jammy.Zhou@amd.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Sonny Jiang <sonny.jiang@amd.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	Leo Liu <leo.liu@amd.com>
Subject: Re: [PATCH] amdgpu/uvd: use kmemdup
Date: Thu, 19 May 2016 13:18:10 +0200	[thread overview]
Message-ID: <573DA0F2.2020503@amd.com> (raw)
In-Reply-To: <1463656317-13828-1-git-send-email-falakreyaz@gmail.com>

Am 19.05.2016 um 13:11 schrieb Muhammad Falak R Wani:
> Use kmemdup when some other buffer is immediately copied into allocated
> region. It replaces call to allocation followed by memcpy, by a single
> call to kmemdup.
>
> Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>

NAK, actually using memcpy() is wrong in the first place.

The UVD BO is in VRAM so the pointer is pointing to IO memory here, so 
this should be memcpy_fromio() instead of memcpy().

Christian.

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> index 01abfc2..c977ab6 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
> @@ -295,12 +295,10 @@ int amdgpu_uvd_suspend(struct amdgpu_device *adev)
>   	size = amdgpu_bo_size(adev->uvd.vcpu_bo);
>   	ptr = adev->uvd.cpu_addr;
>   
> -	adev->uvd.saved_bo = kmalloc(size, GFP_KERNEL);
> +	adev->uvd.saved_bo = kmemdup(ptr, size, GFP_KERNEL);
>   	if (!adev->uvd.saved_bo)
>   		return -ENOMEM;
>   
> -	memcpy(adev->uvd.saved_bo, ptr, size);
> -
>   	return 0;
>   }
>   

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