[PATCH v5 07/13] iommufd/viommu: Add iommufd_viommu_find_dev helper

[Nicolin Chen <nicolinc@nvidia.com>]

This avoids a bigger trouble of exposing struct iommufd_device and struct
iommufd_vdevice in the public header.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 include/linux/iommufd.h        |  8 ++++++++
 drivers/iommu/iommufd/driver.c | 13 +++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 0287a6d00192..dc174d02132b 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -184,6 +184,8 @@ static inline int iommufd_vfio_compat_set_no_iommu(struct iommufd_ctx *ictx)
 struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
 					     size_t size,
 					     enum iommufd_object_type type);
+struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
+				       unsigned long vdev_id);
 #else /* !CONFIG_IOMMUFD_DRIVER */
 static inline struct iommufd_object *
 _iommufd_object_alloc(struct iommufd_ctx *ictx, size_t size,
@@ -191,6 +193,12 @@ _iommufd_object_alloc(struct iommufd_ctx *ictx, size_t size,
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
+
+static inline struct device *
+iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id)
+{
+	return NULL;
+}
 #endif /* CONFIG_IOMMUFD_DRIVER */
 
 /*
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index c0876d3f91c7..3604443f82a1 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -36,3 +36,16 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
 	return ERR_PTR(rc);
 }
 EXPORT_SYMBOL_NS_GPL(_iommufd_object_alloc, IOMMUFD);
+
+/* Caller should xa_lock(&viommu->vdevs) to protect the return value */
+struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
+				       unsigned long vdev_id)
+{
+	struct iommufd_vdevice *vdev;
+
+	lockdep_is_held(&viommu->vdevs.xa_lock);
+
+	vdev = xa_load(&viommu->vdevs, vdev_id);
+	return vdev ? vdev->idev->dev : NULL;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_dev, IOMMUFD);
-- 
2.43.0