Re: [PATCH v5 7/7] iommu/riscv: Paging domain support

[Andrew Jones]

On Tue, May 14, 2024 at 11:16:19AM GMT, Tomasz Jeznach wrote:
..
> +static int riscv_iommu_bond_link(struct riscv_iommu_domain *domain,
> +				 struct device *dev)
> +{
> +	struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> +	struct riscv_iommu_bond *bond;
> +	struct list_head *bonds;
> +
> +	bond = kzalloc(sizeof(*bond), GFP_KERNEL);
> +	if (!bond)
> +		return -ENOMEM;
> +	bond->dev = dev;
> +
> +	/*
> +	 * List of devices attached to the domain is arranged based on
> +	 * managed IOMMU device.
> +	 */
> +
> +	spin_lock(&domain->lock);
> +	list_for_each_rcu(bonds, &domain->bonds)
> +		if (dev_to_iommu(list_entry(bonds, struct riscv_iommu_bond, list)->dev) == iommu)
> +			break;

We should wrap this list_for_each_rcu() in rcu_read_lock() and
rcu_read_unlock().

Thanks,
drew

> +	list_add_rcu(&bond->list, bonds);
> +	spin_unlock(&domain->lock);
> +
> +	/* Synchronize with riscv_iommu_iotlb_inval() sequence. See comment below. */
> +	smp_mb();
> +
> +	return 0;
> +}