[PATCH 1/4] iommu/vt-d: Refactor device_to_iommu() helper

[Lu Baolu]

It is refactored in two ways:

- Make it global so that it could be used in other files.

- Make bus/devfn optional so that callers could ignore these two returned
values when they only want to get the coresponding iommu pointer.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel/iommu.c | 55 +++++++++++--------------------------
 drivers/iommu/intel/svm.c   |  8 +++---
 include/linux/intel-iommu.h |  3 +-
 3 files changed, 21 insertions(+), 45 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index d759e7234e98..de17952ed133 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -778,16 +778,16 @@ is_downstream_to_pci_bridge(struct device *dev, struct device *bridge)
 	return false;
 }
 
-static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn)
+struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn)
 {
 	struct dmar_drhd_unit *drhd = NULL;
+	struct pci_dev *pdev = NULL;
 	struct intel_iommu *iommu;
 	struct device *tmp;
-	struct pci_dev *pdev = NULL;
 	u16 segment = 0;
 	int i;
 
-	if (iommu_dummy(dev))
+	if (!dev || iommu_dummy(dev))
 		return NULL;
 
 	if (dev_is_pci(dev)) {
@@ -818,8 +818,10 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
 				if (pdev && pdev->is_virtfn)
 					goto got_pdev;
 
-				*bus = drhd->devices[i].bus;
-				*devfn = drhd->devices[i].devfn;
+				if (bus && devfn) {
+					*bus = drhd->devices[i].bus;
+					*devfn = drhd->devices[i].devfn;
+				}
 				goto out;
 			}
 
@@ -829,8 +831,10 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
 
 		if (pdev && drhd->include_all) {
 		got_pdev:
-			*bus = pdev->bus->number;
-			*devfn = pdev->devfn;
+			if (bus && devfn) {
+				*bus = pdev->bus->number;
+				*devfn = pdev->devfn;
+			}
 			goto out;
 		}
 	}
@@ -5146,11 +5150,10 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
 			      struct device *dev)
 {
 	int ret;
-	u8 bus, devfn;
 	unsigned long flags;
 	struct intel_iommu *iommu;
 
-	iommu = device_to_iommu(dev, &bus, &devfn);
+	iommu = device_to_iommu(dev, NULL, NULL);
 	if (!iommu)
 		return -ENODEV;
 
@@ -5236,9 +5239,8 @@ static int prepare_domain_attach_device(struct iommu_domain *domain,
 	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
 	struct intel_iommu *iommu;
 	int addr_width;
-	u8 bus, devfn;
 
-	iommu = device_to_iommu(dev, &bus, &devfn);
+	iommu = device_to_iommu(dev, NULL, NULL);
 	if (!iommu)
 		return -ENODEV;
 
@@ -5658,9 +5660,8 @@ static bool intel_iommu_capable(enum iommu_cap cap)
 static struct iommu_device *intel_iommu_probe_device(struct device *dev)
 {
 	struct intel_iommu *iommu;
-	u8 bus, devfn;
 
-	iommu = device_to_iommu(dev, &bus, &devfn);
+	iommu = device_to_iommu(dev, NULL, NULL);
 	if (!iommu)
 		return ERR_PTR(-ENODEV);
 
@@ -5673,9 +5674,8 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
 static void intel_iommu_release_device(struct device *dev)
 {
 	struct intel_iommu *iommu;
-	u8 bus, devfn;
 
-	iommu = device_to_iommu(dev, &bus, &devfn);
+	iommu = device_to_iommu(dev, NULL, NULL);
 	if (!iommu)
 		return;
 
@@ -5825,37 +5825,14 @@ static struct iommu_group *intel_iommu_device_group(struct device *dev)
 	return generic_device_group(dev);
 }
 
-#ifdef CONFIG_INTEL_IOMMU_SVM
-struct intel_iommu *intel_svm_device_to_iommu(struct device *dev)
-{
-	struct intel_iommu *iommu;
-	u8 bus, devfn;
-
-	if (iommu_dummy(dev)) {
-		dev_warn(dev,
-			 "No IOMMU translation for device; cannot enable SVM\n");
-		return NULL;
-	}
-
-	iommu = device_to_iommu(dev, &bus, &devfn);
-	if ((!iommu)) {
-		dev_err(dev, "No IOMMU for device; cannot enable SVM\n");
-		return NULL;
-	}
-
-	return iommu;
-}
-#endif /* CONFIG_INTEL_IOMMU_SVM */
-
 static int intel_iommu_enable_auxd(struct device *dev)
 {
 	struct device_domain_info *info;
 	struct intel_iommu *iommu;
 	unsigned long flags;
-	u8 bus, devfn;
 	int ret;
 
-	iommu = device_to_iommu(dev, &bus, &devfn);
+	iommu = device_to_iommu(dev, NULL, NULL);
 	if (!iommu || dmar_disabled)
 		return -EINVAL;
 
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 6c87c807a0ab..25dd74f27252 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -231,7 +231,7 @@ static LIST_HEAD(global_svm_list);
 int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
 			  struct iommu_gpasid_bind_data *data)
 {
-	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
+	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
 	struct dmar_domain *dmar_domain;
 	struct intel_svm_dev *sdev;
 	struct intel_svm *svm;
@@ -373,7 +373,7 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
 
 int intel_svm_unbind_gpasid(struct device *dev, int pasid)
 {
-	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
+	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
 	struct intel_svm_dev *sdev;
 	struct intel_svm *svm;
 	int ret = -EINVAL;
@@ -430,7 +430,7 @@ static int
 intel_svm_bind_mm(struct device *dev, int flags, struct svm_dev_ops *ops,
 		  struct mm_struct *mm, struct intel_svm_dev **sd)
 {
-	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
+	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
 	struct device_domain_info *info;
 	struct intel_svm_dev *sdev;
 	struct intel_svm *svm = NULL;
@@ -608,7 +608,7 @@ static int intel_svm_unbind_mm(struct device *dev, int pasid)
 	struct intel_svm *svm;
 	int ret = -EINVAL;
 
-	iommu = intel_svm_device_to_iommu(dev);
+	iommu = device_to_iommu(dev, NULL, NULL);
 	if (!iommu)
 		goto out;
 
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 3e8fa1c7a1e6..fc2cfc3db6e1 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -728,6 +728,7 @@ void iommu_flush_write_buffer(struct intel_iommu *iommu);
 int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev);
 struct dmar_domain *find_domain(struct device *dev);
 struct device_domain_info *get_domain_info(struct device *dev);
+struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn);
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
 extern void intel_svm_check(struct intel_iommu *iommu);
@@ -766,8 +767,6 @@ struct intel_svm {
 	struct list_head devs;
 	struct list_head list;
 };
-
-extern struct intel_iommu *intel_svm_device_to_iommu(struct device *dev);
 #else
 static inline void intel_svm_check(struct intel_iommu *iommu) {}
 #endif
-- 
2.17.1