On 11/21/25 11:12, Pierre-Eric Pelloux-Prayer wrote:
> Taking the entity lock is required to guarantee the ordering of
> execution. The next commit will add a check that the lock is
> held.
> 
> Signed-off-by: Pierre-Eric Pelloux-Prayer <[email protected]>

The benchmarking is kind of irrelevant, but adding the other lock should 
actually be the first patch in the series since it is a bug fix (it needs to 
grab the gart window lock at this place of course).

Then the patch needs a CC stable and a Fixes tag to the patch who introduced 
amdgpu_ttm_access_memory_sdma().

With that done: Reviewed-by: Christian König <[email protected]>

Regards,
Christian.

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c | 2 ++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c 
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c
> index a050167e76a4..832d9ae101f0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c
> @@ -35,6 +35,7 @@ static int amdgpu_benchmark_do_move(struct amdgpu_device 
> *adev, unsigned size,
>       struct dma_fence *fence;
>       int i, r;
>  
> +     mutex_lock(&adev->mman.default_entity.lock);
>       stime = ktime_get();
>       for (i = 0; i < n; i++) {
>               r = amdgpu_copy_buffer(adev, &adev->mman.default_entity,
> @@ -47,6 +48,7 @@ static int amdgpu_benchmark_do_move(struct amdgpu_device 
> *adev, unsigned size,
>               if (r)
>                       goto exit_do_move;
>       }
> +     mutex_unlock(&adev->mman.default_entity.lock);
>  
>  exit_do_move:
>       etime = ktime_get();
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 3a0511d1739f..a803af015d05 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -1501,6 +1501,7 @@ static int amdgpu_ttm_access_memory_sdma(struct 
> ttm_buffer_object *bo,
>       if (r)
>               goto out;
>  
> +     mutex_lock(&adev->mman.default_entity.lock);
>       amdgpu_res_first(abo->tbo.resource, offset, len, &src_mm);
>       src_addr = amdgpu_ttm_domain_start(adev, bo->resource->mem_type) +
>               src_mm.start;
> @@ -1512,6 +1513,7 @@ static int amdgpu_ttm_access_memory_sdma(struct 
> ttm_buffer_object *bo,
>                               PAGE_SIZE, 0);
>  
>       fence = amdgpu_ttm_job_submit(adev, job, num_dw);
> +     mutex_unlock(&adev->mman.default_entity.lock);
>  
>       if (!dma_fence_wait_timeout(fence, false, adev->sdma_timeout))
>               r = -ETIMEDOUT;

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