[PATCH] drm/amdgpu: fix max_entries calculation v4

[Pan, Xinhui]

Reviewed-by: xinhui pan <xinhui.pan at amd.com>


> 2020年9月3日 17:03，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
> v4: fix the case that we map less VA range than BO size
> 
> 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 | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 8bc2253939be..d6dcd58a8f1a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1691,13 +1691,13 @@ static int amdgpu_vm_bo_split_mapping(struct amdgpu_device *adev,
> 		uint64_t max_entries;
> 		uint64_t addr, last;
> 
> +		max_entries = mapping->last - start + 1;
> 		if (nodes) {
> 			addr = nodes->start << PAGE_SHIFT;
> -			max_entries = (nodes->size - pfn) *
> -				AMDGPU_GPU_PAGES_IN_CPU_PAGE;
> +			max_entries = min((nodes->size - pfn) *
> +				AMDGPU_GPU_PAGES_IN_CPU_PAGE, max_entries);
> 		} else {
> 			addr = 0;
> -			max_entries = S64_MAX;
> 		}
> 
> 		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;
> 		r = amdgpu_vm_bo_update_mapping(adev, vm, false, false, resv,
> 						start, last, flags, addr,
> 						dma_addr, fence);
> -- 
> 2.17.1
>