[PATCH] drm/amdkfd: Skip handle mapping SVM range with no GPU access

[Sierra Guiza, Alejandro (Alex)]

On 6/29/2023 5:29 PM, Philip Yang wrote:
> If the SVM range has no GPU access or access-in-place attribute,
Just a nit-pick. Shouldn't be no GPU access nor access-in-place?
> validate and map to GPU should skip the range.
>
> Add NULL pointer check if find_first_bit(ctx->bitmap, MAX_GPU_INSTANCE)
> returns MAX_GPU_INSTANCE as gpuidx if ctx->bitmap is empty.
>
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
Reviewed-by: Alex Sierra <alex.sierra at amd.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index 5ff1a5a89d96..479c4f66afa7 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -1522,6 +1522,8 @@ static void *kfd_svm_page_owner(struct kfd_process *p, int32_t gpuidx)
>   	struct kfd_process_device *pdd;
>   
>   	pdd = kfd_process_device_from_gpuidx(p, gpuidx);
> +	if (!pdd)
> +		return NULL;
>   
>   	return SVM_ADEV_PGMAP_OWNER(pdd->dev->adev);
>   }
> @@ -1596,12 +1598,12 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
>   	}
>   
>   	if (bitmap_empty(ctx->bitmap, MAX_GPU_INSTANCE)) {
> -		if (!prange->mapped_to_gpu) {
> +		bitmap_copy(ctx->bitmap, prange->bitmap_access, MAX_GPU_INSTANCE);
> +		if (!prange->mapped_to_gpu ||
> +		    bitmap_empty(ctx->bitmap, MAX_GPU_INSTANCE)) {
>   			r = 0;
>   			goto free_ctx;
>   		}
> -
> -		bitmap_copy(ctx->bitmap, prange->bitmap_access, MAX_GPU_INSTANCE);
>   	}
>   
>   	if (prange->actual_loc && !prange->ttm_res) {