From: Tiwei Bie <tiwei.bie@intel.com>
To: Jason Wang <jasowang@redhat.com>
Cc: mst@redhat.com, virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
virtio-dev@lists.oasis-open.org, wexu@redhat.com,
jfreimann@redhat.com
Subject: Re: [virtio-dev] Re: [PATCH net-next v1 4/5] virtio_ring: add event idx support in packed ring
Date: Wed, 11 Jul 2018 09:09:05 +0800 [thread overview]
Message-ID: <20180711010905.GB28235@debian> (raw)
In-Reply-To: <9ee31221-9f4a-f1c5-0f0b-8d178bb536e9@redhat.com>
On Tue, Jul 10, 2018 at 01:50:03PM +0800, Jason Wang wrote:
> 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.
I'll do it. Thanks!
Best regards,
Tiwei Bie
>
> > + 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
>
next prev parent reply other threads:[~2018-07-11 1:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 7:22 [PATCH net-next v1 0/5] virtio: support packed ring Tiwei Bie
2018-07-09 7:22 ` [PATCH net-next v1 1/5] virtio: add packed ring definitions Tiwei Bie
2018-07-09 7:22 ` [PATCH net-next v1 2/5] virtio_ring: support creating packed ring Tiwei Bie
2018-07-09 7:22 ` [PATCH net-next v1 3/5] virtio_ring: add packed ring support Tiwei Bie
2018-07-09 7:22 ` [PATCH net-next v1 4/5] virtio_ring: add event idx support in packed ring Tiwei Bie
2018-07-10 5:50 ` Jason Wang
2018-07-11 1:09 ` Tiwei Bie [this message]
2018-07-09 7:22 ` [PATCH net-next v1 5/5] virtio_ring: enable " Tiwei Bie
2018-07-10 5:51 ` Jason Wang
2018-07-11 1:07 ` Tiwei Bie
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