Re: [PATCH] iommu/virtio: reverse arguments to list_add

[Jean-Philippe Brucker]

On Tue, May 05, 2020 at 08:47:47PM +0200, Julia Lawall wrote:
> Elsewhere in the file, there is a list_for_each_entry with
> &vdev->resv_regions as the second argument, suggesting that
> &vdev->resv_regions is the list head.  So exchange the
> arguments on the list_add call to put the list head in the
> second argument.
> 
> Fixes: 2a5a31487445 ("iommu/virtio: Add probe request")
> Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxxx>

Thanks for the fix. The reason this hasn't blown up so far is
iommu_alloc_resv_region() initializes region->list, but adding more than
one item would break the list.

Reviewed-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>

> ---
>  drivers/iommu/virtio-iommu.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index d5cac4f46ca5..4e1d11af23c8 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -453,7 +453,7 @@ static int viommu_add_resv_mem(struct viommu_endpoint *vdev,
>  	if (!region)
>  		return -ENOMEM;
>  
> -	list_add(&vdev->resv_regions, &region->list);
> +	list_add(&region->list, &vdev->resv_regions);
>  	return 0;
>  }
>  
>