drm/virtio: add drm_driver.release callback.

Split virtio_gpu_deinit(), move the drm shutdown and release to
virtio_gpu_release().  Drop vqs_ready variable, instead use
drm_dev_{enter,exit,unplug} to avoid touching hardware after
device removal.  Tidy up here and there.

v4: add changelog.
v3: use drm_dev_*().
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20200211135805.24436-1-kraxel@redhat.com

drivers/gpu/drm/virtio/virtgpu_display.c

@@ -368,6 +368,5 @@ void virtio_gpu_modeset_fini(struct virtio_gpu_device *vgdev)
 
 	for (i = 0 ; i < vgdev->num_scanouts; ++i)
 		kfree(vgdev->outputs[i].edid);
-	drm_atomic_helper_shutdown(vgdev->ddev);
 	drm_mode_config_cleanup(vgdev->ddev);
 }

drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -31,6 +31,7 @@
 #include <linux/pci.h>
 
 #include <drm/drm.h>
+#include <drm/drm_atomic_helper.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
 
@@ -135,7 +136,8 @@ static void virtio_gpu_remove(struct virtio_device *vdev)
 {
 	struct drm_device *dev = vdev->priv;
 
-	drm_dev_unregister(dev);
+	drm_dev_unplug(dev);
+	drm_atomic_helper_shutdown(dev);
 	virtio_gpu_deinit(dev);
 	drm_dev_put(dev);
 }
@@ -214,4 +216,6 @@ static struct drm_driver driver = {
 	.major = DRIVER_MAJOR,
 	.minor = DRIVER_MINOR,
 	.patchlevel = DRIVER_PATCHLEVEL,
+
+	.release = virtio_gpu_release,
 };

drivers/gpu/drm/virtio/virtgpu_drv.h

@@ -32,6 +32,7 @@
 #include <linux/virtio_gpu.h>
 
 #include <drm/drm_atomic.h>
+#include <drm/drm_drv.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_gem.h>
@@ -177,7 +178,6 @@ struct virtio_gpu_device {
 	struct virtio_gpu_queue ctrlq;
 	struct virtio_gpu_queue cursorq;
 	struct kmem_cache *vbufs;
-	bool vqs_ready;
 
 	bool disable_notify;
 	bool pending_notify;
@@ -219,6 +219,7 @@ extern struct drm_ioctl_desc virtio_gpu_ioctls[DRM_VIRTIO_NUM_IOCTLS];
 /* virtio_kms.c */
 int virtio_gpu_init(struct drm_device *dev);
 void virtio_gpu_deinit(struct drm_device *dev);
+void virtio_gpu_release(struct drm_device *dev);
 int virtio_gpu_driver_open(struct drm_device *dev, struct drm_file *file);
 void virtio_gpu_driver_postclose(struct drm_device *dev, struct drm_file *file);
 

drivers/gpu/drm/virtio/virtgpu_kms.c

@@ -199,7 +199,6 @@ int virtio_gpu_init(struct drm_device *dev)
 	virtio_gpu_modeset_init(vgdev);
 
 	virtio_device_ready(vgdev->vdev);
-	vgdev->vqs_ready = true;
 
 	if (num_capsets)
 		virtio_gpu_get_capsets(vgdev, num_capsets);
@@ -234,12 +233,16 @@ void virtio_gpu_deinit(struct drm_device *dev)
 	struct virtio_gpu_device *vgdev = dev->dev_private;
 
 	flush_work(&vgdev->obj_free_work);
-	vgdev->vqs_ready = false;
 	flush_work(&vgdev->ctrlq.dequeue_work);
 	flush_work(&vgdev->cursorq.dequeue_work);
 	flush_work(&vgdev->config_changed_work);
 	vgdev->vdev->config->reset(vgdev->vdev);
 	vgdev->vdev->config->del_vqs(vgdev->vdev);
+}
+
+void virtio_gpu_release(struct drm_device *dev)
+{
+	struct virtio_gpu_device *vgdev = dev->dev_private;
 
 	virtio_gpu_modeset_fini(vgdev);
 	virtio_gpu_free_vbufs(vgdev);

drivers/gpu/drm/virtio/virtgpu_vq.c

@@ -330,7 +330,14 @@ static void virtio_gpu_queue_ctrl_sgs(struct virtio_gpu_device *vgdev,
 {
 	struct virtqueue *vq = vgdev->ctrlq.vq;
 	bool notify = false;
-	int ret;
+	int ret, idx;
+
+	if (!drm_dev_enter(vgdev->ddev, &idx)) {
+		if (fence && vbuf->objs)
+			virtio_gpu_array_unlock_resv(vbuf->objs);
+		free_vbuf(vgdev, vbuf);
+		return;
+	}
 
 	if (vgdev->has_indirect)
 		elemcnt = 1;
@@ -338,14 +345,6 @@ static void virtio_gpu_queue_ctrl_sgs(struct virtio_gpu_device *vgdev,
 again:
 	spin_lock(&vgdev->ctrlq.qlock);
 
-	if (!vgdev->vqs_ready) {
-		spin_unlock(&vgdev->ctrlq.qlock);
-
-		if (fence && vbuf->objs)
-			virtio_gpu_array_unlock_resv(vbuf->objs);
-		return;
-	}
-
 	if (vq->num_free < elemcnt) {
 		spin_unlock(&vgdev->ctrlq.qlock);
 		wait_event(vgdev->ctrlq.ack_queue, vq->num_free >= elemcnt);
@@ -379,6 +378,7 @@ static void virtio_gpu_queue_ctrl_sgs(struct virtio_gpu_device *vgdev,
 		else
 			virtqueue_notify(vq);
 	}
+	drm_dev_exit(idx);
 }
 
 static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
@@ -460,12 +460,13 @@ static void virtio_gpu_queue_cursor(struct virtio_gpu_device *vgdev,
 {
 	struct virtqueue *vq = vgdev->cursorq.vq;
 	struct scatterlist *sgs[1], ccmd;
+	int idx, ret, outcnt;
 	bool notify;
-	int ret;
-	int outcnt;
 
-	if (!vgdev->vqs_ready)
+	if (!drm_dev_enter(vgdev->ddev, &idx)) {
+		free_vbuf(vgdev, vbuf);
 		return;
+	}
 
 	sg_init_one(&ccmd, vbuf->buf, vbuf->size);
 	sgs[0] = &ccmd;
@@ -490,6 +491,8 @@ static void virtio_gpu_queue_cursor(struct virtio_gpu_device *vgdev,
 
 	if (notify)
 		virtqueue_notify(vq);
+
+	drm_dev_exit(idx);
 }
 
 /* just create gem objects for userspace and long lived objects,