[PATCH 1/2] drm/amdgpu: Fix a bug on flag table_freed

[Christian König]

Am 30.05.21 um 00:51 schrieb Eric Huang:
> table_freed will be always true when mapping a memory with size
> bigger than 2MB. The problem is page table's entries are always
> existed, but existing mapping depends on page talbe's bo, so
> using a check of page table's bo existed will resolve the issue.
>
> Signed-off-by: Eric Huang <jinhuieric.huang at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 0dee2e8797c7..95b94c95adac 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1582,9 +1582,11 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
>   			 * completely covered by the range and so potentially still in use.
>   			 */
>   			while (cursor.pfn < frag_start) {
> +				/* Make sure previous mapping existed */
> +				if (cursor.entry->base.bo)
> +					params->table_freed = true;

In general this is the correct approach, but I would push that decision 
into the amdgpu_vm_free_pts() function.

>   				amdgpu_vm_free_pts(adev, params->vm, &cursor);

So that we have here something like

params->table_freed |= amdgpu_vm_free_pts(..);


Regards,
Christian.

>   				amdgpu_vm_pt_next(adev, &cursor);
> -				params->table_freed = true;
>   			}
>   
>   		} else if (frag >= shift) {