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

[Xuan Zhuo]

On Fri, 1 Jul 2022 02:28:46 -0400, "Michael S. Tsirkin" <mst at 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 at 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
>