[PATCH 3/5 v5] 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.

v5: Fix possible race and sleep via mutex (@olv)

Signed-off-by: Gurchetan Singh <gurchetansi...@chromium.org>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h   | 2 ++
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 8 ++++++++
 drivers/gpu/drm/virtio/virtgpu_kms.c   | 3 +++
 3 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h 
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 72c1d9b59dfe..0596d9618554 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -209,6 +209,8 @@ struct virtio_gpu_device {
 
 struct virtio_gpu_fpriv {
        uint32_t ctx_id;
+       bool context_initiated;
+       struct mutex context_lock;
 };
 
 /* virtio_ioctl.c */
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c 
b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index de04f80f737d..c1a6cb4ec375 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -44,10 +44,18 @@ void virtio_gpu_create_context(struct drm_device *dev,
        if (!vgdev->has_virgl_3d)
                return;
 
+       mutex_lock(&vfpriv->context_lock);
+       if (vfpriv->context_initiated)
+               goto out_unlock;
+
        get_task_comm(dbgname, current);
        virtio_gpu_cmd_context_create(vgdev, vfpriv->ctx_id,
                                      strlen(dbgname), dbgname);
        virtio_gpu_notify(vgdev);
+       vfpriv->context_initiated = true;
+
+out_unlock:
+       mutex_unlock(&vfpriv->context_lock);
 }
 
 static int virtio_gpu_map_ioctl(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c 
b/drivers/gpu/drm/virtio/virtgpu_kms.c
index f7e3712502ca..424729cb81d1 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -258,6 +258,8 @@ int virtio_gpu_driver_open(struct drm_device *dev, struct 
drm_file *file)
        if (!vfpriv)
                return -ENOMEM;
 
+       mutex_init(&vfpriv->context_lock);
+
        handle = ida_alloc(&vgdev->ctx_id_ida, GFP_KERNEL);
        if (handle < 0) {
                kfree(vfpriv);
@@ -281,6 +283,7 @@ void virtio_gpu_driver_postclose(struct drm_device *dev, 
struct drm_file *file)
        vfpriv = file->driver_priv;
 
        virtio_gpu_context_destroy(vgdev, vfpriv->ctx_id);
+       mutex_destroy(&vfpriv->context_lock);
        kfree(vfpriv);
        file->driver_priv = NULL;
 }
-- 
2.25.0.265.gbab2e86ba0-goog

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