On Mon, Jan 22, 2018 at 10:56:41AM +0800, Tiwei Bie wrote:
> On Fri, Jan 19, 2018 at 04:55:53PM +0100, Olivier Matz wrote:
> > When using vector Rx mode (use_simple_rx = 1), vq->vq_descx[] is not
> > kept up to date. To properly detach the mbufs in this case, browse
> > sw_ring[] instead, as it's done in virtqueue_rxvq_flush().
> >
> > Since we need virtio_get_queue_type(), also move this function in
> > virtqueue.h as a static inline.
> >
> > Fixes: fc3d66212fed ("virtio: add vector Rx")
> > Cc: sta...@dpdk.org
> >
> > Signed-off-by: Olivier Matz <olivier.m...@6wind.com>
> > ---
> >
> > Tiwei,
> >
> > While it passes my test plan, please carefully check that what I did in
> > virtqueue_detatch_unused() is correct. I tried to reproduce what is done
> > in virtqueue_rxvq_flush(), but I may be mistaking due to the different
> > ring layout assumption and mbuf management between standard and vector.
> >
> > Thanks
> > Olivier
> >
> >
> > drivers/net/virtio/virtio_ethdev.c | 11 -----------
> > drivers/net/virtio/virtqueue.c | 17 +++++++++++++++--
> > drivers/net/virtio/virtqueue.h | 11 +++++++++++
> > 3 files changed, 26 insertions(+), 13 deletions(-)
> >
> [...]
> > struct rte_mbuf *
> > virtqueue_detatch_unused(struct virtqueue *vq)
> > {
> > + struct virtio_hw *hw = vq->hw;
> > struct rte_mbuf *cookie;
> > int idx;
> > + int type = virtio_get_queue_type(hw, vq->vq_queue_index);
> > +
> > + if (vq == NULL)
> > + return NULL;
> >
> > - if (vq != NULL)
> > - for (idx = 0; idx < vq->vq_nentries; idx++) {
> > + for (idx = 0; idx < vq->vq_nentries; idx++) {
> > + if (hw->use_simple_rx && type == VTNET_RQ) {
> > + cookie = vq->sw_ring[idx];
> > + if (cookie != NULL) {
> > + vq->sw_ring[idx] = NULL;
>
> Thanks for working on this!
>
> The vq->sw_ring[idx] isn't zeroed during Rx. So besides the
> check of (cookie != NULL), some other check is also needed
> to avoid freeing the mbufs already delivered to application.
>
> The mbufs in below interval belong to application:
>
> start: sw_ring[vq->vq_avail_idx & (vq->vq_nentries - 1)] (included)
> end: sw_ring[(vq->vq_avail_idx + vq->vq_free_cnt) & (vq->vq_nentries - 1)]
> (excluded)
>
> PS. (vq->vq_avail_idx & (vq->vq_nentries - 1)) can be greater than
> (vq->vq_avail_idx + vq->vq_free_cnt) & (vq->vq_nentries - 1).
Thank you for the review. What about something like this?
struct rte_mbuf *
virtqueue_detach_unused(struct virtqueue *vq)
{
struct rte_mbuf *cookie;
struct virtio_hw *hw;
uint16_t start, end;
int type, idx;
if (vq == NULL)
return NULL;
hw = vq->hw;
type = virtio_get_queue_type(hw, vq->vq_queue_index);
start = vq->vq_avail_idx & (vq->vq_nentries - 1);
end = (vq->vq_avail_idx + vq->vq_free_cnt) & (vq->vq_nentries - 1);
end = (vq->vq_avail_idx + vq->vq_free_cnt) & (vq->vq_nentries - 1);
for (idx = 0; idx < vq->vq_nentries; idx++) {
if (hw->use_simple_rx && type == VTNET_RQ) {
if (start <= end && idx >= start && idx < end)
continue;
if (start > end && (idx >= start || idx < end))
continue;
cookie = vq->sw_ring[idx];
if (cookie == NULL)
continue;
vq->sw_ring[idx] = NULL;
return cookie;
} else {
cookie = vq->vq_descx[idx].cookie;
if (cookie != NULL) {
vq->vq_descx[idx].cookie = NULL;
return cookie;
}
}
}
return NULL;
}
Regards,
Olivier
