Messages in this thread | | | Subject | Re: [PATCH net-next v1 4/5] virtio_ring: add event idx support in packed ring | From | Jason Wang <> | Date | Tue, 10 Jul 2018 13:50:03 +0800 |
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On 2018年07月09日 15:22, Tiwei Bie wrote: > @@ -1059,9 +1059,19 @@ static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq) > * suppressions. */ > virtio_mb(vq->weak_barriers); > > + old = vq->next_avail_idx - vq->num_added; > + new = vq->next_avail_idx; > + vq->num_added = 0; > + > snapshot = *(u32 *)vq->vring_packed.device;
I think we should use READ_ONCE() to prevent compiler from re-reading.
> + off_wrap = virtio16_to_cpu(_vq->vdev, (__virtio16)(snapshot & 0xffff)); > flags = virtio16_to_cpu(_vq->vdev, (__virtio16)(snapshot >> 16)) & 0x3; > > + wrap_counter = off_wrap >> 15; > + event_idx = off_wrap & ~(1 << 15); > + if (wrap_counter != vq->avail_wrap_counter) > + event_idx -= vq->vring_packed.num;
Thanks
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