[PATCH v2] drm/amdkfd: Confirm list is non-empty before utilizing list_first_entry in kfd_topology.c

[Felix Kuehling]

On 2023-12-22 06:53, Srinivasan Shanmugam wrote:
> Before using list_first_entry, make sure to check that list is not
> empty, if list is empty return -ENODATA.
>
> Fixes the below:
> drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_topology.c:1347 kfd_create_indirect_link_prop() warn: can 'gpu_link' even be NULL?
> drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_topology.c:1428 kfd_add_peer_prop() warn: can 'iolink1' even be NULL?
> drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_topology.c:1433 kfd_add_peer_prop() warn: can 'iolink2' even be NULL?
>
> 'Fixes: 0f28cca87e9a ("drm/amdkfd: Extend KFD device topology to surface
> peer-to-peer links")'
> Suggested-by: Lijo Lazar <lijo.lazar at amd.com>
> Suggested-by: Felix Kuehling <Felix.Kuehling 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>


> ---
>
> v2:
>    Changed to "if (list_empty(&kdev->io_link_props)) return -ENODATA;"
> (Lijo)
>
>   drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 21 ++++++++++++---------
>   1 file changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> index dc7c8312e8c7..1fc9d4616564 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> @@ -1342,10 +1342,11 @@ static int kfd_create_indirect_link_prop(struct kfd_topology_device *kdev, int g
>   		num_cpu++;
>   	}
>   
> +	if (list_empty(&kdev->io_link_props))
> +		return -ENODATA;
> +
>   	gpu_link = list_first_entry(&kdev->io_link_props,
> -					struct kfd_iolink_properties, list);
> -	if (!gpu_link)
> -		return -ENOMEM;
> +				    struct kfd_iolink_properties, list);
>   
>   	for (i = 0; i < num_cpu; i++) {
>   		/* CPU <--> GPU */
> @@ -1423,15 +1424,17 @@ static int kfd_add_peer_prop(struct kfd_topology_device *kdev,
>   				peer->gpu->adev))
>   		return ret;
>   
> +	if (list_empty(&kdev->io_link_props))
> +		return -ENODATA;
> +
>   	iolink1 = list_first_entry(&kdev->io_link_props,
> -							struct kfd_iolink_properties, list);
> -	if (!iolink1)
> -		return -ENOMEM;
> +				   struct kfd_iolink_properties, list);
> +
> +	if (list_empty(&peer->io_link_props))
> +		return -ENODATA;
>   
>   	iolink2 = list_first_entry(&peer->io_link_props,
> -							struct kfd_iolink_properties, list);
> -	if (!iolink2)
> -		return -ENOMEM;
> +				   struct kfd_iolink_properties, list);
>   
>   	props = kfd_alloc_struct(props);
>   	if (!props)