[PATCH] drm/amdkfd: Fix 'node' NULL check in 'svm_range_get_range_boundaries()'

[Felix Kuehling]

On 2024-01-10 03:26, Srinivasan Shanmugam wrote:
> Range interval [start, last] is ordered by rb_tree, rb_prev, rb_next
> return value still needs NULL check, thus modified from "node" to "rb_node".
>
> Fixes the below:
> drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_svm.c:2691 svm_range_get_range_boundaries() warn: can 'node' even be NULL?
>
> Suggested-by: Philip Yang <Philip.Yang at amd.com>
> Cc: Felix Kuehling <Felix.Kuehling at amd.com>
> Cc: Christian König <christian.koenig at amd.com>
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>

Reviewed-by: Felix Kuehling <felix.kuehling at amd.com>


> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index 3b78e48832e9..6aa032731ddc 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -2656,6 +2656,7 @@ svm_range_get_range_boundaries(struct kfd_process *p, int64_t addr,
>   {
>   	struct vm_area_struct *vma;
>   	struct interval_tree_node *node;
> +	struct rb_node *rb_node;
>   	unsigned long start_limit, end_limit;
>   
>   	vma = vma_lookup(p->mm, addr << PAGE_SHIFT);
> @@ -2678,16 +2679,15 @@ svm_range_get_range_boundaries(struct kfd_process *p, int64_t addr,
>   	if (node) {
>   		end_limit = min(end_limit, node->start);
>   		/* Last range that ends before the fault address */
> -		node = container_of(rb_prev(&node->rb),
> -				    struct interval_tree_node, rb);
> +		rb_node = rb_prev(&node->rb);
>   	} else {
>   		/* Last range must end before addr because
>   		 * there was no range after addr
>   		 */
> -		node = container_of(rb_last(&p->svms.objects.rb_root),
> -				    struct interval_tree_node, rb);
> +		rb_node = rb_last(&p->svms.objects.rb_root);
>   	}
> -	if (node) {
> +	if (rb_node) {
> +		node = container_of(rb_node, struct interval_tree_node, rb);
>   		if (node->last >= addr) {
>   			WARN(1, "Overlap with prev node and page fault addr\n");
>   			return -EFAULT;