Re: [PATCH v2 1/3] virtio: add ability to delete vq through a pointer

[Pankaj Gupta <pagupta@redhat.com>]

> 
> On 2019/12/4 16:33, Pankaj Gupta wrote:
> > 
> >> From: Pan Nengyuan <pannengyuan@huawei.com>
> >>
> >> Devices tend to maintain vq pointers, allow deleting them trough a vq
> >> pointer.
> >>
> >> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> >> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> >> ---
> >> Changes v2 to v1:
> >> - add a new function virtio_delete_queue to cleanup vq through a vq
> >> pointer
> >> ---
> >>  hw/virtio/virtio.c         | 16 +++++++++++-----
> >>  include/hw/virtio/virtio.h |  2 ++
> >>  2 files changed, 13 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> >> index 04716b5..6de3cfd 100644
> >> --- a/hw/virtio/virtio.c
> >> +++ b/hw/virtio/virtio.c
> >> @@ -2330,17 +2330,23 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev,
> >> int
> >> queue_size,
> >>      return &vdev->vq[i];
> >>  }
> >>  
> >> +void virtio_delete_queue(VirtQueue *vq)
> >> +{
> >> +    vq->vring.num = 0;
> >> +    vq->vring.num_default = 0;
> >> +    vq->handle_output = NULL;
> >> +    vq->handle_aio_output = NULL;
> >> +    g_free(vq->used_elems);
> >> +    vq->used_elems = NULL;
> >> +}
> >> +
> >>  void virtio_del_queue(VirtIODevice *vdev, int n)
> >>  {
> >>      if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
> >>          abort();
> >>      }
> >>  
> >> -    vdev->vq[n].vring.num = 0;
> >> -    vdev->vq[n].vring.num_default = 0;
> >> -    vdev->vq[n].handle_output = NULL;
> >> -    vdev->vq[n].handle_aio_output = NULL;
> >> -    g_free(vdev->vq[n].used_elems);
> >> +    virtio_delete_queue(&vdev->vq[n]);
> >>  }
> >>  
> >>  static void virtio_set_isr(VirtIODevice *vdev, int value)
> >> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> >> index c32a815..e18756d 100644
> >> --- a/include/hw/virtio/virtio.h
> >> +++ b/include/hw/virtio/virtio.h
> >> @@ -183,6 +183,8 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int
> >> queue_size,
> >>  
> >>  void virtio_del_queue(VirtIODevice *vdev, int n);
> >>  
> >> +void virtio_delete_queue(VirtQueue *vq);
> >> +
> >>  void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
> >>                      unsigned int len);
> >>  void virtqueue_flush(VirtQueue *vq, unsigned int count);
> >> --
> >> 2.7.2.windows.1
> >>
> >>
> > Overall it ooks good to me.
> > 
> > Just one point: e.g in virtio_rng: "virtio_rng_device_unrealize" function
> > We are doing :     virtio_del_queue(vdev, 0);
> > 
> > One can directly call "virtio_delete_queue". It can become confusing
> > to call multiple functions for same purpose. Instead, Can we make
> > "virtio_delete_queue" static inline?
> > 
> yes, It will be a little confused, but I think it will have the same
> problem if we make "virtio_delete_queue" static inline. We can directly
> call it aslo. （e.g virtio-serial-bus.c virtio-balloon.c).
> 
> How about replacing the function name to make it more clear (e.g
> virtio_delete_queue -> virtio_queue_cleanup) ? It's too similar between
> "virtio_del_queue" and "virtio_delete_queue".

I am just thinking if we need these two separate functions.

Yes, changing name of virtio_delete_queue -> virtio_queue_cleanup
should be good enough.

Thanks,
Pankaj

> 
> > Other than that:
> > Reviewed-by: Pankaj Gupta <pagupta@redhat.com>
> > 
> >>
> >>
> > 
> > 
> > .
> > 
> 
> 
>