[PATCH] drm/amdgpu: fix max_entries calculation v3

[Pan, Xinhui]

> 2020年9月2日 23:21，Christian König <ckoenig.leichtzumerken at gmail.com> 写道：
> 
> Calculate the correct value for max_entries or we might run after the
> page_address array.
> 
> v2: Xinhui pointed out we don't need the shift
> v3: use local copy of start and simplify some calculation
> 
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Fixes: 1e691e244487 drm/amdgpu: stop allocating dummy GTT nodes
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 8bc2253939be..7cbee1a7ec84 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1697,7 +1697,7 @@ static int amdgpu_vm_bo_split_mapping(struct amdgpu_device *adev,
> 				AMDGPU_GPU_PAGES_IN_CPU_PAGE;
> 		} else {
> 			addr = 0;
> -			max_entries = S64_MAX;
> +			max_entries = mapping->last - start + 1;
> 		}
> 
> 		if (pages_addr) {
> @@ -1727,7 +1727,7 @@ static int amdgpu_vm_bo_split_mapping(struct amdgpu_device *adev,
> 			addr += pfn << PAGE_SHIFT;
> 		}
> 
> -		last = min((uint64_t)mapping->last, start + max_entries - 1);
> +		last = start + max_entries - 1;

I am not sure if we calculate the max_entries by nodes->size. does it work in that case?

> 		r = amdgpu_vm_bo_update_mapping(adev, vm, false, false, resv,
> 						start, last, flags, addr,
> 						dma_addr, fence);
> -- 
> 2.17.1
> 
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