Messages in this thread | | | Subject | Re: [RFC v2 5/7] virtio: unmask F_NEXT flag in desc_extra | Date | Thu, 18 Aug 2022 11:05:37 +0800 | From | Xuan Zhuo <> |
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On Wed, 17 Aug 2022 21:57:16 +0800, Guo Zhi <qtxuning1999@sjtu.edu.cn> wrote: > We didn't unmask F_NEXT flag in desc_extra in the end of a chain, > unmask it so that we can access desc_extra to get next information.
I think we should state the purpose of this.
> > Signed-off-by: Guo Zhi <qtxuning1999@sjtu.edu.cn> > --- > drivers/virtio/virtio_ring.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index a5ec724c01d8..1c1b3fa376a2 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -567,7 +567,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > } > /* Last one doesn't continue. */ > desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT); > - if (!indirect && vq->use_dma_api) > + if (!indirect) > vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &= > ~VRING_DESC_F_NEXT; > > @@ -584,6 +584,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > total_sg * sizeof(struct vring_desc), > VRING_DESC_F_INDIRECT, > false); > + vq->split.desc_extra[head & (vq->split.vring.num - 1)].flags &= > + ~VRING_DESC_F_NEXT;
This seems unnecessary.
> } > > /* We're using some buffers from the free list. */ > @@ -693,7 +695,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > /* Put back on free list: unmap first-level descriptors and find end */ > i = head; > > - while (vq->split.vring.desc[i].flags & nextflag) { > + while (vq->split.desc_extra[i].flags & nextflag) {
nextflag is __virtio16
You can use VRING_DESC_F_NEXT directly.
Thanks.
> vring_unmap_one_split(vq, i); > i = vq->split.desc_extra[i].next; > vq->vq.num_free++; > -- > 2.17.1 >
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