iommu: Make iommu_report_device_fault() return void

As the iommu_report_device_fault() has been converted to auto-respond a
page fault if it fails to enqueue it, there's no need to return a code
in any case. Make it return void.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240212012227.119381-17-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: LuBaolu

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -1455,7 +1455,7 @@ arm_smmu_find_master(struct arm_smmu_device *smmu, u32 sid)
 /* IRQ and event handlers */
 static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
 {
-	int ret;
+	int ret = 0;
 	u32 perm = 0;
 	struct arm_smmu_master *master;
 	bool ssid_valid = evt[0] & EVTQ_0_SSV;
@@ -1511,7 +1511,7 @@ static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
 		goto out_unlock;
 	}
 
-	ret = iommu_report_device_fault(master->dev, &fault_evt);
+	iommu_report_device_fault(master->dev, &fault_evt);
 out_unlock:
 	mutex_unlock(&smmu->streams_mutex);
 	return ret;

drivers/iommu/intel/svm.c

@@ -561,14 +561,11 @@ static int prq_to_iommu_prot(struct page_req_dsc *req)
 	return prot;
 }
 
-static int intel_svm_prq_report(struct intel_iommu *iommu, struct device *dev,
-				struct page_req_dsc *desc)
+static void intel_svm_prq_report(struct intel_iommu *iommu, struct device *dev,
+				 struct page_req_dsc *desc)
 {
 	struct iopf_fault event = { };
 
-	if (!dev || !dev_is_pci(dev))
-		return -ENODEV;
-
 	/* Fill in event data for device specific processing */
 	event.fault.type = IOMMU_FAULT_PAGE_REQ;
 	event.fault.prm.addr = (u64)desc->addr << VTD_PAGE_SHIFT;
@@ -601,7 +598,7 @@ static int intel_svm_prq_report(struct intel_iommu *iommu, struct device *dev,
 		event.fault.prm.private_data[0] = ktime_to_ns(ktime_get());
 	}
 
-	return iommu_report_device_fault(dev, &event);
+	iommu_report_device_fault(dev, &event);
 }
 
 static void handle_bad_prq_event(struct intel_iommu *iommu,
@@ -704,12 +701,10 @@ static irqreturn_t prq_event_thread(int irq, void *d)
 		if (!pdev)
 			goto bad_req;
 
-		if (intel_svm_prq_report(iommu, &pdev->dev, req))
-			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
-		else
-			trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
-					 req->priv_data[0], req->priv_data[1],
-					 iommu->prq_seq_number++);
+		intel_svm_prq_report(iommu, &pdev->dev, req);
+		trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
+				 req->priv_data[0], req->priv_data[1],
+				 iommu->prq_seq_number++);
 		pci_dev_put(pdev);
 prq_advance:
 		head = (head + sizeof(*req)) & PRQ_RING_MASK;

drivers/iommu/io-pgfault.c

@@ -176,26 +176,22 @@ static struct iopf_group *iopf_group_alloc(struct iommu_fault_param *iopf_param,
  * freed after the device has stopped generating page faults (or the iommu
  * hardware has been set to block the page faults) and the pending page faults
  * have been flushed.
- *
- * Return: 0 on success and <0 on error.
  */
-int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
+void iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
 {
 	struct iommu_fault *fault = &evt->fault;
 	struct iommu_fault_param *iopf_param;
 	struct iopf_group abort_group = {};
 	struct iopf_group *group;
-	int ret;
 
 	iopf_param = iopf_get_dev_fault_param(dev);
 	if (WARN_ON(!iopf_param))
-		return -ENODEV;
+		return;
 
 	if (!(fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) {
-		ret = report_partial_fault(iopf_param, fault);
+		report_partial_fault(iopf_param, fault);
 		iopf_put_dev_fault_param(iopf_param);
 		/* A request that is not the last does not need to be ack'd */
-		return ret;
 	}
 
 	/*
@@ -207,33 +203,28 @@ int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
 	 * leaving, otherwise partial faults will be stuck.
 	 */
 	group = iopf_group_alloc(iopf_param, evt, &abort_group);
-	if (group == &abort_group) {
-		ret = -ENOMEM;
+	if (group == &abort_group)
 		goto err_abort;
-	}
 
 	group->domain = get_domain_for_iopf(dev, fault);
-	if (!group->domain) {
-		ret = -EINVAL;
+	if (!group->domain)
 		goto err_abort;
-	}
 
 	/*
 	 * On success iopf_handler must call iopf_group_response() and
 	 * iopf_free_group()
 	 */
-	ret = group->domain->iopf_handler(group);
-	if (ret)
+	if (group->domain->iopf_handler(group))
 		goto err_abort;
-	return 0;
+
+	return;
 
 err_abort:
 	iopf_group_response(group, IOMMU_PAGE_RESP_FAILURE);
 	if (group == &abort_group)
 		__iopf_free_group(group);
 	else
 		iopf_free_group(group);
-	return ret;
 }
 EXPORT_SYMBOL_GPL(iommu_report_device_fault);
 

include/linux/iommu.h

@@ -1545,7 +1545,7 @@ struct iopf_queue *iopf_queue_alloc(const char *name);
 void iopf_queue_free(struct iopf_queue *queue);
 int iopf_queue_discard_partial(struct iopf_queue *queue);
 void iopf_free_group(struct iopf_group *group);
-int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt);
+void iommu_report_device_fault(struct device *dev, struct iopf_fault *evt);
 void iopf_group_response(struct iopf_group *group,
 			 enum iommu_page_response_code status);
 #else
@@ -1583,10 +1583,9 @@ static inline void iopf_free_group(struct iopf_group *group)
 {
 }
 
-static inline int
+static inline void
 iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
 {
-	return -ENODEV;
 }
 
 static inline void iopf_group_response(struct iopf_group *group,