vfio: Make vfio_(un)register_notifier accept a vfio_device

All callers have a struct vfio_device trivially available, pass it in
directly and avoid calling the expensive vfio_group_get_from_dev().
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/1-v4-8045e76bf00b+13d-vfio_mdev_no_group_jgg@nvidia.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -810,8 +810,8 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	vgpu->group_notifier.notifier_call = intel_vgpu_group_notifier;
 
 	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
-	ret = vfio_register_notifier(vfio_dev->dev, VFIO_IOMMU_NOTIFY, &events,
-				&vgpu->iommu_notifier);
+	ret = vfio_register_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, &events,
+				     &vgpu->iommu_notifier);
 	if (ret != 0) {
 		gvt_vgpu_err("vfio_register_notifier for iommu failed: %d\n",
 			ret);
@@ -819,8 +819,8 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	}
 
 	events = VFIO_GROUP_NOTIFY_SET_KVM;
-	ret = vfio_register_notifier(vfio_dev->dev, VFIO_GROUP_NOTIFY, &events,
-				&vgpu->group_notifier);
+	ret = vfio_register_notifier(vfio_dev, VFIO_GROUP_NOTIFY, &events,
+				     &vgpu->group_notifier);
 	if (ret != 0) {
 		gvt_vgpu_err("vfio_register_notifier for group failed: %d\n",
 			ret);
@@ -873,12 +873,12 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	vgpu->vfio_group = NULL;
 
 undo_register:
-	vfio_unregister_notifier(vfio_dev->dev, VFIO_GROUP_NOTIFY,
-					&vgpu->group_notifier);
+	vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY,
+				 &vgpu->group_notifier);
 
 undo_iommu:
-	vfio_unregister_notifier(vfio_dev->dev, VFIO_IOMMU_NOTIFY,
-					&vgpu->iommu_notifier);
+	vfio_unregister_notifier(vfio_dev, VFIO_IOMMU_NOTIFY,
+				 &vgpu->iommu_notifier);
 out:
 	return ret;
 }
@@ -907,13 +907,13 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 
 	intel_gvt_release_vgpu(vgpu);
 
-	ret = vfio_unregister_notifier(vgpu->vfio_device.dev, VFIO_IOMMU_NOTIFY,
-					&vgpu->iommu_notifier);
+	ret = vfio_unregister_notifier(&vgpu->vfio_device, VFIO_IOMMU_NOTIFY,
+				       &vgpu->iommu_notifier);
 	drm_WARN(&i915->drm, ret,
 		 "vfio_unregister_notifier for iommu failed: %d\n", ret);
 
-	ret = vfio_unregister_notifier(vgpu->vfio_device.dev, VFIO_GROUP_NOTIFY,
-					&vgpu->group_notifier);
+	ret = vfio_unregister_notifier(&vgpu->vfio_device, VFIO_GROUP_NOTIFY,
+				       &vgpu->group_notifier);
 	drm_WARN(&i915->drm, ret,
 		 "vfio_unregister_notifier for group failed: %d\n", ret);
 

drivers/s390/cio/vfio_ccw_ops.c

@@ -183,7 +183,7 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
 
 	private->nb.notifier_call = vfio_ccw_mdev_notifier;
 
-	ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
+	ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY,
 				     &events, &private->nb);
 	if (ret)
 		return ret;
@@ -204,8 +204,7 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
 
 out_unregister:
 	vfio_ccw_unregister_dev_regions(private);
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
-				 &private->nb);
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
 	return ret;
 }
 
@@ -223,7 +222,7 @@ static void vfio_ccw_mdev_close_device(struct vfio_device *vdev)
 
 	cp_free(&private->cp);
 	vfio_ccw_unregister_dev_regions(private);
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY, &private->nb);
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
 }
 
 static ssize_t vfio_ccw_mdev_read_io_region(struct vfio_ccw_private *private,

drivers/s390/crypto/vfio_ap_ops.c

@@ -1406,21 +1406,21 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev)
 	matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier;
 	events = VFIO_GROUP_NOTIFY_SET_KVM;
 
-	ret = vfio_register_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
-				     &events, &matrix_mdev->group_notifier);
+	ret = vfio_register_notifier(vdev, VFIO_GROUP_NOTIFY, &events,
+				     &matrix_mdev->group_notifier);
 	if (ret)
 		return ret;
 
 	matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
 	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
-	ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
-				     &events, &matrix_mdev->iommu_notifier);
+	ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, &events,
+				     &matrix_mdev->iommu_notifier);
 	if (ret)
 		goto out_unregister_group;
 	return 0;
 
 out_unregister_group:
-	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	return ret;
 }
@@ -1430,9 +1430,9 @@ static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
 	struct ap_matrix_mdev *matrix_mdev =
 		container_of(vdev, struct ap_matrix_mdev, vdev);
 
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY,
 				 &matrix_mdev->iommu_notifier);
-	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	vfio_ap_mdev_unset_kvm(matrix_mdev);
 }

drivers/vfio/vfio.c

@@ -2484,19 +2484,16 @@ static int vfio_unregister_group_notifier(struct vfio_group *group,
 	return ret;
 }
 
-int vfio_register_notifier(struct device *dev, enum vfio_notify_type type,
-			   unsigned long *events, struct notifier_block *nb)
+int vfio_register_notifier(struct vfio_device *device,
+			   enum vfio_notify_type type, unsigned long *events,
+			   struct notifier_block *nb)
 {
-	struct vfio_group *group;
+	struct vfio_group *group = device->group;
 	int ret;
 
-	if (!dev || !nb || !events || (*events == 0))
+	if (!nb || !events || (*events == 0))
 		return -EINVAL;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
 	switch (type) {
 	case VFIO_IOMMU_NOTIFY:
 		ret = vfio_register_iommu_notifier(group, events, nb);
@@ -2507,25 +2504,20 @@ int vfio_register_notifier(struct device *dev, enum vfio_notify_type type,
 	default:
 		ret = -EINVAL;
 	}
-
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_register_notifier);
 
-int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type,
+int vfio_unregister_notifier(struct vfio_device *device,
+			     enum vfio_notify_type type,
 			     struct notifier_block *nb)
 {
-	struct vfio_group *group;
+	struct vfio_group *group = device->group;
 	int ret;
 
-	if (!dev || !nb)
+	if (!nb)
 		return -EINVAL;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
 	switch (type) {
 	case VFIO_IOMMU_NOTIFY:
 		ret = vfio_unregister_iommu_notifier(group, nb);
@@ -2536,8 +2528,6 @@ int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type,
 	default:
 		ret = -EINVAL;
 	}
-
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_unregister_notifier);

include/linux/vfio.h

@@ -178,11 +178,11 @@ enum vfio_notify_type {
 /* events for VFIO_GROUP_NOTIFY */
 #define VFIO_GROUP_NOTIFY_SET_KVM	BIT(0)
 
-extern int vfio_register_notifier(struct device *dev,
+extern int vfio_register_notifier(struct vfio_device *device,
 				  enum vfio_notify_type type,
 				  unsigned long *required_events,
 				  struct notifier_block *nb);
-extern int vfio_unregister_notifier(struct device *dev,
+extern int vfio_unregister_notifier(struct vfio_device *device,
 				    enum vfio_notify_type type,
 				    struct notifier_block *nb);