[PATCH v4 2/9] iommu: Replace sva_iommu with iommu_attach_handle

[Lu Baolu <baolu.lu@linux.intel.com>]

The struct sva_iommu represents a bond of an SVA domain and a device.
It is functionally equivalent to the iommu_attach_handle. To avoid
code duplication, replace sva_iommu with the iommu_attach_handle and
remove the code that manages sva_iommu.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 include/linux/iommu.h      | 28 +++++------------
 include/linux/uacce.h      |  2 +-
 drivers/dma/idxd/idxd.h    |  2 +-
 drivers/dma/idxd/cdev.c    |  4 +--
 drivers/iommu/iommu-sva.c  | 61 ++++++++++++++++----------------------
 drivers/misc/uacce/uacce.c |  2 +-
 6 files changed, 38 insertions(+), 61 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2e925b5eba53..be9c9a10169d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -39,7 +39,6 @@ struct iommu_domain;
 struct iommu_domain_ops;
 struct iommu_dirty_ops;
 struct notifier_block;
-struct iommu_sva;
 struct iommu_dma_cookie;
 struct iommu_fault_param;
 
@@ -986,20 +985,9 @@ struct iommu_fwspec {
 /* ATS is supported */
 #define IOMMU_FWSPEC_PCI_RC_ATS			(1 << 0)
 
-/**
- * struct iommu_sva - handle to a device-mm bond
- */
-struct iommu_sva {
-	struct device			*dev;
-	struct iommu_domain		*domain;
-	struct list_head		handle_item;
-	refcount_t			users;
-};
-
 struct iommu_mm_data {
 	u32			pasid;
 	struct list_head	sva_domains;
-	struct list_head	sva_handles;
 };
 
 int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
@@ -1527,24 +1515,24 @@ static inline u32 mm_get_enqcmd_pasid(struct mm_struct *mm)
 }
 
 void mm_pasid_drop(struct mm_struct *mm);
-struct iommu_sva *iommu_sva_bind_device(struct device *dev,
-					struct mm_struct *mm);
-void iommu_sva_unbind_device(struct iommu_sva *handle);
-u32 iommu_sva_get_pasid(struct iommu_sva *handle);
+struct iommu_attach_handle *iommu_sva_bind_device(struct device *dev,
+						  struct mm_struct *mm);
+void iommu_sva_unbind_device(struct iommu_attach_handle *handle);
+u32 iommu_sva_get_pasid(struct iommu_attach_handle *handle);
 struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
 					    struct mm_struct *mm);
 #else
-static inline struct iommu_sva *
+static inline struct iommu_attach_handle *
 iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
 {
-	return NULL;
+	return ERR_PTR(-ENODEV);
 }
 
-static inline void iommu_sva_unbind_device(struct iommu_sva *handle)
+static inline void iommu_sva_unbind_device(struct iommu_attach_handle *handle)
 {
 }
 
-static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle)
+static inline u32 iommu_sva_get_pasid(struct iommu_attach_handle *handle)
 {
 	return IOMMU_PASID_INVALID;
 }
diff --git a/include/linux/uacce.h b/include/linux/uacce.h
index e290c0269944..1548119c89ae 100644
--- a/include/linux/uacce.h
+++ b/include/linux/uacce.h
@@ -97,7 +97,7 @@ struct uacce_queue {
 	struct mutex mutex;
 	enum uacce_q_state state;
 	u32 pasid;
-	struct iommu_sva *handle;
+	struct iommu_attach_handle *handle;
 	struct address_space *mapping;
 };
 
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index a4099a1e2340..3ee89e9cb049 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -335,7 +335,7 @@ struct idxd_device {
 	struct idxd_wq **wqs;
 	struct idxd_engine **engines;
 
-	struct iommu_sva *sva;
+	struct iommu_attach_handle *sva;
 	unsigned int pasid;
 
 	int num_groups;
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index 8078ab9acfbc..a029bda92615 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -45,7 +45,7 @@ struct idxd_user_context {
 	unsigned int pasid;
 	struct mm_struct *mm;
 	unsigned int flags;
-	struct iommu_sva *sva;
+	struct iommu_attach_handle *sva;
 	struct idxd_dev idxd_dev;
 	u64 counters[COUNTER_MAX];
 	int id;
@@ -225,7 +225,7 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp)
 	struct idxd_wq *wq;
 	struct device *dev, *fdev;
 	int rc = 0;
-	struct iommu_sva *sva;
+	struct iommu_attach_handle *sva;
 	unsigned int pasid;
 	struct idxd_cdev *idxd_cdev;
 
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index 640acc804e8c..35ac2e4836e9 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -41,7 +41,6 @@ static struct iommu_mm_data *iommu_alloc_mm_data(struct mm_struct *mm, struct de
 	}
 	iommu_mm->pasid = pasid;
 	INIT_LIST_HEAD(&iommu_mm->sva_domains);
-	INIT_LIST_HEAD(&iommu_mm->sva_handles);
 	/*
 	 * Make sure the write to mm->iommu_mm is not reordered in front of
 	 * initialization to iommu_mm fields. If it does, readers may see a
@@ -67,13 +66,17 @@ static struct iommu_mm_data *iommu_alloc_mm_data(struct mm_struct *mm, struct de
  *
  * On error, returns an ERR_PTR value.
  */
-struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
+struct iommu_attach_handle *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
 {
+	struct iommu_group *group = dev->iommu_group;
+	struct iommu_attach_handle *handle;
 	struct iommu_mm_data *iommu_mm;
 	struct iommu_domain *domain;
-	struct iommu_sva *handle;
 	int ret;
 
+	if (!group)
+		return ERR_PTR(-ENODEV);
+
 	mutex_lock(&iommu_sva_lock);
 
 	/* Allocate mm->pasid if necessary. */
@@ -83,18 +86,11 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
 		goto out_unlock;
 	}
 
-	list_for_each_entry(handle, &mm->iommu_mm->sva_handles, handle_item) {
-		if (handle->dev == dev) {
-			refcount_inc(&handle->users);
-			mutex_unlock(&iommu_sva_lock);
-			return handle;
-		}
-	}
-
-	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
-	if (!handle) {
-		ret = -ENOMEM;
-		goto out_unlock;
+	/* A bond already exists, just take a reference`. */
+	handle = iommu_attach_handle_get(group, iommu_mm->pasid);
+	if (handle) {
+		mutex_unlock(&iommu_sva_lock);
+		return handle;
 	}
 
 	/* Search for an existing domain. */
@@ -110,7 +106,7 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
 	domain = iommu_sva_domain_alloc(dev, mm);
 	if (!domain) {
 		ret = -ENOMEM;
-		goto out_free_handle;
+		goto out_unlock;
 	}
 
 	ret = iommu_attach_device_pasid(domain, dev, iommu_mm->pasid);
@@ -120,17 +116,14 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
 	list_add(&domain->next, &mm->iommu_mm->sva_domains);
 
 out:
-	refcount_set(&handle->users, 1);
-	list_add(&handle->handle_item, &mm->iommu_mm->sva_handles);
+	handle = iommu_attach_handle_get(group, iommu_mm->pasid);
 	mutex_unlock(&iommu_sva_lock);
-	handle->dev = dev;
-	handle->domain = domain;
+	handle->priv = dev;
+
 	return handle;
 
 out_free_domain:
 	iommu_domain_free(domain);
-out_free_handle:
-	kfree(handle);
 out_unlock:
 	mutex_unlock(&iommu_sva_lock);
 	return ERR_PTR(ret);
@@ -145,30 +138,26 @@ EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
  * not be issuing any more transaction for this PASID. All outstanding page
  * requests for this PASID must have been flushed to the IOMMU.
  */
-void iommu_sva_unbind_device(struct iommu_sva *handle)
+void iommu_sva_unbind_device(struct iommu_attach_handle *handle)
 {
 	struct iommu_domain *domain = handle->domain;
 	struct iommu_mm_data *iommu_mm = domain->mm->iommu_mm;
-	struct device *dev = handle->dev;
+	struct device *dev = handle->priv;
 
 	mutex_lock(&iommu_sva_lock);
-	if (!refcount_dec_and_test(&handle->users)) {
-		mutex_unlock(&iommu_sva_lock);
-		return;
-	}
-	list_del(&handle->handle_item);
-
-	iommu_detach_device_pasid(domain, dev, iommu_mm->pasid);
-	if (--domain->users == 0) {
-		list_del(&domain->next);
-		iommu_domain_free(domain);
+	iommu_attach_handle_put(handle);
+	if (refcount_read(&handle->users) == 1) {
+		iommu_detach_device_pasid(domain, dev, iommu_mm->pasid);
+		if (--domain->users == 0) {
+			list_del(&domain->next);
+			iommu_domain_free(domain);
+		}
 	}
 	mutex_unlock(&iommu_sva_lock);
-	kfree(handle);
 }
 EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
 
-u32 iommu_sva_get_pasid(struct iommu_sva *handle)
+u32 iommu_sva_get_pasid(struct iommu_attach_handle *handle)
 {
 	struct iommu_domain *domain = handle->domain;
 
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index bdc2e6fda782..b325097421c1 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -106,7 +106,7 @@ static long uacce_fops_compat_ioctl(struct file *filep,
 static int uacce_bind_queue(struct uacce_device *uacce, struct uacce_queue *q)
 {
 	u32 pasid;
-	struct iommu_sva *handle;
+	struct iommu_attach_handle *handle;
 
 	if (!(uacce->flags & UACCE_DEV_SVA))
 		return 0;
-- 
2.34.1