Add rid_notifier array to struct dev_iommu to facilitate
requester notification of IOMMU faults.

Signed-off-by: Sergey Temerkhanov <sergey.temerkhanov@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iommu/iommu.c | 9 +++++++++
 include/linux/iommu.h | 4 ++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index a4b606c591da..3789c16806a1 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -354,6 +354,7 @@ static struct dev_iommu *dev_iommu_get(struct device *dev)
 		return NULL;
 
 	mutex_init(&param->lock);
+	xa_init(&param->rid_notifiers);
 	dev->iommu = param;
 	return param;
 }
@@ -361,8 +362,16 @@ static struct dev_iommu *dev_iommu_get(struct device *dev)
 void dev_iommu_free(struct device *dev)
 {
 	struct dev_iommu *param = dev->iommu;
+	struct rid_notifier *notifier;
+	unsigned long rid;
 
 	dev->iommu = NULL;
+
+	xa_for_each(&param->rid_notifiers, rid, notifier)
+		kfree(notifier);
+
+	xa_destroy(&param->rid_notifiers);
+
 	if (param->fwspec) {
 		fwnode_handle_put(param->fwspec->iommu_fwnode);
 		kfree(param->fwspec);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 4ddb63a3f2cf..2062623fdf32 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -795,6 +795,8 @@ struct iommu_fault_param {
  * @pci_32bit_workaround: Limit DMA allocations to 32-bit IOVAs
  * @require_direct: device requires IOMMU_RESV_DIRECT regions
  * @shadow_on_flush: IOTLB flushes are used to sync shadow tables
+ * @rid_notifiers: holds pointers and data to the notifier functions for
+ *                   specific RIDs
  *
  * TODO: migrate other per device data pointers under iommu_dev_data, e.g.
  *	struct iommu_group	*iommu_group;
@@ -810,6 +812,8 @@ struct dev_iommu {
 	u32				pci_32bit_workaround:1;
 	u32				require_direct:1;
 	u32				shadow_on_flush:1;
+
+	struct xarray			rid_notifiers;
 };
 
 int iommu_device_register(struct iommu_device *iommu,
-- 
2.43.0