[PATCH 6/7] iommu: Use right way to retrieve iommu_ops

[Lu Baolu]

The common iommu_ops is hooked to both device and domain. When a helper
has both device and domain pointer, the way to get the iommu_ops looks
messy in iommu core. This sorts out the way to get iommu_ops. The device
related helpers go through device pointer, while the domain related ones
go through domain pointer.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 include/linux/iommu.h |  8 ++++++++
 drivers/iommu/iommu.c | 25 ++++++++++++++-----------
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index aa5486243892..111b3e9c79bb 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -385,6 +385,14 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
 	};
 }
 
+static inline const struct iommu_ops *dev_iommu_ops_get(struct device *dev)
+{
+	if (dev && dev->iommu && dev->iommu->iommu_dev)
+		return dev->iommu->iommu_dev->ops;
+
+	return NULL;
+}
+
 #define IOMMU_BUS_NOTIFY_PRIORITY		0
 #define IOMMU_GROUP_NOTIFY_ADD_DEVICE		1 /* Device added */
 #define IOMMU_GROUP_NOTIFY_DEL_DEVICE		2 /* Pre Device removed */
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 5230c6d90ece..6631e2ea44df 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -764,6 +764,7 @@ EXPORT_SYMBOL_GPL(iommu_group_set_name);
 static int iommu_create_device_direct_mappings(struct iommu_group *group,
 					       struct device *dev)
 {
+	const struct iommu_ops *ops = dev_iommu_ops_get(dev);
 	struct iommu_domain *domain = group->default_domain;
 	struct iommu_resv_region *entry;
 	struct list_head mappings;
@@ -785,8 +786,8 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
 		dma_addr_t start, end, addr;
 		size_t map_size = 0;
 
-		if (domain->ops->apply_resv_region)
-			domain->ops->apply_resv_region(dev, domain, entry);
+		if (ops->apply_resv_region)
+			ops->apply_resv_region(dev, domain, entry);
 
 		start = ALIGN(entry->start, pg_size);
 		end   = ALIGN(entry->start + entry->length, pg_size);
@@ -831,8 +832,10 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
 static bool iommu_is_attach_deferred(struct iommu_domain *domain,
 				     struct device *dev)
 {
-	if (domain->ops->is_attach_deferred)
-		return domain->ops->is_attach_deferred(domain, dev);
+	const struct iommu_ops *ops = dev_iommu_ops_get(dev);
+
+	if (ops->is_attach_deferred)
+		return ops->is_attach_deferred(domain, dev);
 
 	return false;
 }
@@ -1251,10 +1254,10 @@ int iommu_page_response(struct device *dev,
 	struct iommu_fault_event *evt;
 	struct iommu_fault_page_request *prm;
 	struct dev_iommu *param = dev->iommu;
+	const struct iommu_ops *ops = dev_iommu_ops_get(dev);
 	bool has_pasid = msg->flags & IOMMU_PAGE_RESP_PASID_VALID;
-	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
 
-	if (!domain || !domain->ops->page_response)
+	if (!ops || !ops->page_response)
 		return -ENODEV;
 
 	if (!param || !param->fault_param)
@@ -1295,7 +1298,7 @@ int iommu_page_response(struct device *dev,
 			msg->pasid = 0;
 		}
 
-		ret = domain->ops->page_response(dev, evt, msg);
+		ret = ops->page_response(dev, evt, msg);
 		list_del(&evt->list);
 		kfree(evt);
 		break;
@@ -1758,10 +1761,10 @@ static int __iommu_group_dma_attach(struct iommu_group *group)
 
 static int iommu_group_do_probe_finalize(struct device *dev, void *data)
 {
-	struct iommu_domain *domain = data;
+	const struct iommu_ops *ops = dev_iommu_ops_get(dev);
 
-	if (domain->ops->probe_finalize)
-		domain->ops->probe_finalize(dev);
+	if (ops->probe_finalize)
+		ops->probe_finalize(dev);
 
 	return 0;
 }
@@ -2020,7 +2023,7 @@ EXPORT_SYMBOL_GPL(iommu_attach_device);
 
 int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain)
 {
-	const struct iommu_ops *ops = domain->ops;
+	const struct iommu_ops *ops = dev_iommu_ops_get(dev);
 
 	if (ops->is_attach_deferred && ops->is_attach_deferred(domain, dev))
 		return __iommu_attach_device(domain, dev);
-- 
2.25.1