Re: [PATCH v11 02/40] virtio: struct virtio_config_ops add callbacks for queue_reset

Xuan Zhuo
2022-07-01T06:43:40Z

On Fri, 1 Jul 2022 02:28:46 -0400, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Wed, Jun 29, 2022 at 02:56:18PM +0800, Xuan Zhuo wrote:
> > reset can be divided into the following four steps (example):
> > 1. transport: notify the device to reset the queue
> > 2. vring: recycle the buffer submitted
> > 3. vring: reset/resize the vring (may re-alloc)
> > 4. transport: mmap vring to device, and enable the queue
> >
> > In order to support queue reset, add two callbacks(reset_vq,
> > enable_reset_vq) in struct virtio_config_ops to implement steps 1 and 4.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> > include/linux/virtio_config.h | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> > diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> > index b47c2e7ed0ee..ded51b0d4823 100644
> > --- a/include/linux/virtio_config.h
> > +++ b/include/linux/virtio_config.h
> > @@ -78,6 +78,16 @@ struct virtio_shm_region {
> > * @set_vq_affinity: set the affinity for a virtqueue (optional).
> > * @get_vq_affinity: get the affinity for a virtqueue (optional).
> > * @get_shm_region: get a shared memory region based on the index.
> > + * @reset_vq: reset a queue individually (optional).
> > + * vq: the virtqueue
> > + * Returns 0 on success or error status
> > + * reset_vq will guarantee that the callbacks are disabled and synchronized.
> > + * Except for the callback, the caller should guarantee that the vring is
> > + * not accessed by any functions of virtqueue.
> > + * @enable_reset_vq: enable a reset queue
> > + * vq: the virtqueue
> > + * Returns 0 on success or error status
> > + * If reset_vq is set, then enable_reset_vq must also be set.
> > */
> > typedef void vq_callback_t(struct virtqueue *);
> > struct virtio_config_ops {
> > @@ -104,6 +114,8 @@ struct virtio_config_ops {
> > int index);
> > bool (*get_shm_region)(struct virtio_device *vdev,
> > struct virtio_shm_region *region, u8 id);
> > + int (*reset_vq)(struct virtqueue *vq);
> > + int (*enable_reset_vq)(struct virtqueue *vq);
> > };
>
> The names need some tweaking.
> I came up with
> int (*disable_vq_and_reset)(struct virtqueue *vq);
> int (*enable_vq_after_reset)(struct virtqueue *vq);

OK, I will use these two names in the next version.

Hope Jason likes it too.

Thanks.

>
>
> > /* If driver didn't advertise the feature, it will never appear. */
> > --
> > 2.31.0
>