RE: [PATCH v7 10/28] iommufd/access: Bypass access->ops->unmap for internal use

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Friday, June 27, 2025 3:35 AM
> 
> +int iommufd_access_notify_unmap(struct io_pagetable *iopt, unsigned long
> iova,
> +				unsigned long length)
>  {
>  	struct iommufd_ioas *ioas =
>  		container_of(iopt, struct iommufd_ioas, iopt);
>  	struct iommufd_access *access;
>  	unsigned long index;
> +	int ret = 0;
> 
>  	xa_lock(&ioas->iopt.access_list);
> +	/* Bypass any unmap if there is an internal access */
> +	xa_for_each(&ioas->iopt.access_list, index, access) {
> +		if (iommufd_access_is_internal(access)) {
> +			ret = -EBUSY;
> +			goto unlock;
> +		}
> +	}
> +

hmm all those checks are per iopt. Could do one-off check in
iopt_unmap_iova_range() and store the result in a local flag.

Then use that flag to decide whether to return -EBUSY if
area->num_accesses is true in the loop.

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>