[PATCH 3/5] drm/virtio: track whether or not a context has been initiated

[Gurchetan Singh]

Use an atomic variable to track whether a context has been
initiated.

v2: Fix possible race (@olv)

Signed-off-by: Gurchetan Singh <gurchetansingh at chromium.org>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h   | 1 +
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 3 +++
 drivers/gpu/drm/virtio/virtgpu_kms.c   | 1 +
 3 files changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 72c1d9b59dfe..ca505984f8ab 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -209,6 +209,7 @@ struct virtio_gpu_device {
 
 struct virtio_gpu_fpriv {
 	uint32_t ctx_id;
+	atomic_t context_initiated;
 };
 
 /* virtio_ioctl.c */
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 896c3f419a6d..a98884462944 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -44,6 +44,9 @@ void virtio_gpu_create_context(struct drm_device *dev,
 	if (!vgdev->has_virgl_3d)
 		return;
 
+	if (!atomic_add_unless(&vfpriv->context_initiated, 1, 1))
+		return;
+
 	get_task_comm(dbgname, current);
 	virtio_gpu_cmd_context_create(vgdev, vfpriv->ctx_id,
 				      strlen(dbgname), dbgname);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 282558576527..25248bad3fc4 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -263,6 +263,7 @@ int virtio_gpu_driver_open(struct drm_device *dev, struct drm_file *file)
 	}
 
 	vfpriv->ctx_id = handle + 1;
+	atomic_set(&vfpriv->context_initiated, 0);
 	file->driver_priv = vfpriv;
 	virtio_gpu_create_context(dev, file);
 	return 0;
-- 
2.25.0.265.gbab2e86ba0-goog