Re: [PATCH v11 09/40] virtio_ring: split: extract the logic of alloc state and extra

Xuan Zhuo
2022-07-04T02:04:52Z

On Fri, 1 Jul 2022 16:55:05 +0800, Jason Wang <jasowang@redhat.com> wrote:
>
> 在 2022/6/29 14:56, Xuan Zhuo 写道:
> > Separate the logic of creating desc_state, desc_extra, and subsequent
> > patches will call it independently.
> >
> > Since only the structure vring is passed into __vring_new_virtqueue(),
> > when creating the function vring_alloc_state_extra_split(), we prefer to
> > use vring_virtqueue_split as a parameter, and it will be more convenient
> > to pass vring_virtqueue_split to some subsequent functions.
> >
> > So a new vring_virtqueue_split variable is added in
> > __vring_new_virtqueue().
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> > drivers/virtio/virtio_ring.c | 58 +++++++++++++++++++++++++-----------
> > 1 file changed, 40 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index a9ceb9c16c54..cedd340d6db7 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -204,6 +204,7 @@ struct vring_virtqueue {
> > #endif
> > };
> >
> > +static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
> >
> > /*
> > * Helpers.
> > @@ -939,6 +940,32 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
> > return NULL;
> > }
> >
> > +static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring)
> > +{
> > + struct vring_desc_state_split *state;
> > + struct vring_desc_extra *extra;
> > + u32 num = vring->vring.num;
> > +
> > + state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
> > + if (!state)
> > + goto err_state;
> > +
> > + extra = vring_alloc_desc_extra(num);
> > + if (!extra)
> > + goto err_extra;
> > +
> > + memset(state, 0, num * sizeof(struct vring_desc_state_split));
> > +
> > + vring->desc_state = state;
> > + vring->desc_extra = extra;
> > + return 0;
> > +
> > +err_extra:
> > + kfree(state);
> > +err_state:
> > + return -ENOMEM;
> > +}
> > +
> > static void vring_free_split(struct vring_virtqueue_split *vring,
> > struct virtio_device *vdev)
> > {
> > @@ -2224,7 +2251,7 @@ EXPORT_SYMBOL_GPL(vring_interrupt);
> >
> > /* Only available for split ring */
> > struct virtqueue *__vring_new_virtqueue(unsigned int index,
> > - struct vring vring,
> > + struct vring _vring,
> > struct virtio_device *vdev,
> > bool weak_barriers,
> > bool context,
> > @@ -2232,7 +2259,9 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
> > void (*callback)(struct virtqueue *),
> > const char *name)
> > {
> > + struct vring_virtqueue_split vring = {};
>
>
> Nit: to reduce the change-set, let's use vring_split here?

Will fix.

Thanks.

>
> Other looks good.
>
> Thanks
>
>
> > struct vring_virtqueue *vq;
> > + int err;
> >
> > if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
> > return NULL;
> > @@ -2261,7 +2290,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
> > vq->split.queue_dma_addr = 0;
> > vq->split.queue_size_in_bytes = 0;
> >
> > - vq->split.vring = vring;
> > + vq->split.vring = _vring;
> > vq->split.avail_flags_shadow = 0;
> > vq->split.avail_idx_shadow = 0;
> >
> > @@ -2273,30 +2302,23 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
> > vq->split.avail_flags_shadow);
> > }
> >
> > - vq->split.desc_state = kmalloc_array(vring.num,
> > - sizeof(struct vring_desc_state_split), GFP_KERNEL);
> > - if (!vq->split.desc_state)
> > - goto err_state;
> > + vring.vring = _vring;
> >
> > - vq->split.desc_extra = vring_alloc_desc_extra(vring.num);
> > - if (!vq->split.desc_extra)
> > - goto err_extra;
> > + err = vring_alloc_state_extra_split(&vring);
> > + if (err) {
> > + kfree(vq);
> > + return NULL;
> > + }
> >
> > - memset(vq->split.desc_state, 0, vring.num *
> > - sizeof(struct vring_desc_state_split));
> > + vq->split.desc_state = vring.desc_state;
> > + vq->split.desc_extra = vring.desc_extra;
> >
> > - virtqueue_init(vq, vq->split.vring.num);
> > + virtqueue_init(vq, vring.vring.num);
> >
> > spin_lock(&vdev->vqs_list_lock);
> > list_add_tail(&vq->vq.list, &vdev->vqs);
> > spin_unlock(&vdev->vqs_list_lock);
> > return &vq->vq;
> > -
> > -err_extra:
> > - kfree(vq->split.desc_state);
> > -err_state:
> > - kfree(vq);
> > - return NULL;
> > }
> > EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
> >
>