| Message ID | 20200213231805.622-4-gurchetansingh@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | *** Delay context create cmd *** | expand |
On Thu, Feb 13, 2020 at 3:18 PM Gurchetan Singh <gurchetansingh@chromium.org> wrote: > > Use an atomic variable to track whether a context has been > initiated. > > v2: Fix possible race (@olv) > > Signed-off-by: Gurchetan Singh <gurchetansingh@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; > + How does this work? When thread A and B enter this function at the same time, and thread B returns early, it is possible that thread B queues other commands before thread A has the chance to queue virtio_gpu_cmd_context_create. > 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 >
On Fri, Feb 14, 2020 at 11:27 AM Chia-I Wu <olvaffe@gmail.com> wrote: > > On Thu, Feb 13, 2020 at 3:18 PM Gurchetan Singh > <gurchetansingh@chromium.org> wrote: > > > > Use an atomic variable to track whether a context has been > > initiated. > > > > v2: Fix possible race (@olv) > > > > Signed-off-by: Gurchetan Singh <gurchetansingh@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; > > + > How does this work? When thread A and B enter this function at the > same time, and thread B returns early, it is possible that thread B > queues other commands before thread A has the chance to queue > virtio_gpu_cmd_context_create. Good catch, I'll add a spinlock in v3. > > > 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 > >
On Fri, Feb 14, 2020 at 6:29 PM Gurchetan Singh <gurchetansingh@chromium.org> wrote: > > On Fri, Feb 14, 2020 at 11:27 AM Chia-I Wu <olvaffe@gmail.com> wrote: > > > > On Thu, Feb 13, 2020 at 3:18 PM Gurchetan Singh > > <gurchetansingh@chromium.org> wrote: > > > > > > Use an atomic variable to track whether a context has been > > > initiated. > > > > > > v2: Fix possible race (@olv) > > > > > > Signed-off-by: Gurchetan Singh <gurchetansingh@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; > > > + > > How does this work? When thread A and B enter this function at the > > same time, and thread B returns early, it is possible that thread B > > queues other commands before thread A has the chance to queue > > virtio_gpu_cmd_context_create. > > Good catch, I'll add a spinlock in v3. virtio_gpu_cmd_context_create can sleep. You will need a mutex (or figure out another way to do the lazy initialization). > > > > > > 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 > > >
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;
Use an atomic variable to track whether a context has been initiated. v2: Fix possible race (@olv) Signed-off-by: Gurchetan Singh <gurchetansingh@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(+)