> From: Lu Baolu <baolu...@linux.intel.com>
> Sent: Saturday, June 25, 2022 8:52 PM
>
> +struct iommu_domain_info {
> + struct intel_iommu *iommu;
> + unsigned int refcnt;
> + u16 did;
> +};
> +
> struct dmar_domain {
> int nid; /* node id */
> -
> - unsigned int iommu_refcnt[DMAR_UNITS_SUPPORTED];
> - /* Refcount of devices per iommu */
> -
> -
> - u16 iommu_did[DMAR_UNITS_SUPPORTED];
> - /* Domain ids per IOMMU. Use u16
> since
> - * domain ids are 16 bit wide
> according
> - * to VT-d spec, section 9.3 */
It'd make sense to keep the comments when moving above fields.
> + spin_lock(&iommu->lock);
> + curr = xa_load(&domain->iommu_array, iommu->seq_id);
> + if (curr) {
> + curr->refcnt++;
> + kfree(info);
> + goto success;
Not a fan of adding a label for success. Just putting two lines (unlock+
return) here is clearer.
> + ret = xa_err(xa_store(&domain->iommu_array, iommu->seq_id,
> + info, GFP_ATOMIC));
check xa_err in separate line.
>
> static void domain_detach_iommu(struct dmar_domain *domain,
> struct intel_iommu *iommu)
> {
> - int num;
> + struct iommu_domain_info *info;
>
> spin_lock(&iommu->lock);
> - domain->iommu_refcnt[iommu->seq_id] -= 1;
> - if (domain->iommu_refcnt[iommu->seq_id] == 0) {
> - num = domain->iommu_did[iommu->seq_id];
> - clear_bit(num, iommu->domain_ids);
> + info = xa_load(&domain->iommu_array, iommu->seq_id);
> + if (--info->refcnt == 0) {
> + clear_bit(info->did, iommu->domain_ids);
> + xa_erase(&domain->iommu_array, iommu->seq_id);
> domain_update_iommu_cap(domain);
> - domain->iommu_did[iommu->seq_id] = 0;
> + kfree(info);
domain->nid may still point to the node of the removed iommu.
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