[PATCH v5 08/10] iommufd: Add iommufd_ctx_has_group()

[Yi Liu <yi.l.liu@xxxxxxxxx>]

to check if any device within the given iommu_group has been bound with
the iommufd_ctx. This helpful for the checking on device ownership for
the devices which have been bound but cannot be bound to any other iommufd
as the iommu_group has been bound.

Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 drivers/iommu/iommufd/device.c | 29 +++++++++++++++++++++++++++++
 include/linux/iommufd.h        |  8 ++++++++
 2 files changed, 37 insertions(+)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 81466b97023f..5e5f7912807b 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -98,6 +98,35 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_device_bind, IOMMUFD);
 
+/**
+ * iommufd_ctx_has_group - True if the struct device is bound to this ictx
+ * @ictx: iommufd file descriptor
+ * @group: Pointer to a physical iommu_group struct
+ *
+ * True if a iommufd_device_bind() is present for any device within the
+ * group.
+ */
+bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group)
+{
+	struct iommufd_object *obj;
+	unsigned long index;
+
+	if (!ictx || !group)
+		return false;
+
+	xa_lock(&ictx->objects);
+	xa_for_each(&ictx->objects, index, obj) {
+		if (obj->type == IOMMUFD_OBJ_DEVICE &&
+		    container_of(obj, struct iommufd_device, obj)->group == group) {
+			xa_unlock(&ictx->objects);
+			return true;
+		}
+	}
+	xa_unlock(&ictx->objects);
+	return false;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_ctx_has_group, IOMMUFD);
+
 /**
  * iommufd_device_unbind - Undo iommufd_device_bind()
  * @idev: Device returned by iommufd_device_bind()
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 68cd65274e28..e49c16cd6831 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -16,6 +16,7 @@ struct page;
 struct iommufd_ctx;
 struct iommufd_access;
 struct file;
+struct iommu_group;
 
 struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
 					   struct device *dev, u32 *id);
@@ -56,6 +57,7 @@ void iommufd_ctx_get(struct iommufd_ctx *ictx);
 #if IS_ENABLED(CONFIG_IOMMUFD)
 struct iommufd_ctx *iommufd_ctx_from_file(struct file *file);
 void iommufd_ctx_put(struct iommufd_ctx *ictx);
+bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group);
 
 int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
 			     unsigned long length, struct page **out_pages,
@@ -77,6 +79,12 @@ static inline void iommufd_ctx_put(struct iommufd_ctx *ictx)
 {
 }
 
+static inline bool iommufd_ctx_has_group(struct iommufd_ctx *ictx,
+					 struct iommu_group *group)
+{
+	return false;
+}
+
 static inline int iommufd_access_pin_pages(struct iommufd_access *access,
 					   unsigned long iova,
 					   unsigned long length,
-- 
2.34.1