Re: [Qemu-devel] [PATCH v11 04/12] net: merge qemu_deliver_packet and qemu_deliver_packet_iov

[Yang Hongyang]

On 09/22/2015 04:14 PM, Jason Wang wrote:
> On 09/22/2015 03:44 PM, Yang Hongyang wrote:
> > Hi Jason,
> >
> >    Thanks for the review,
> >
> > On 09/22/2015 03:30 PM, Jason Wang wrote:
> > > On 09/16/2015 08:16 PM, Yang Hongyang wrote:
> > > > qemu_deliver_packet_iov already have the compat delivery, we
> > > > can drop qemu_deliver_packet.
> > > >
> > > > Signed-off-by: Yang Hongyang <address@hidden>
> > > > ---
> > > >    include/net/net.h |  5 -----
> > > >    net/net.c         | 40 +++++++---------------------------------
> > > >    net/queue.c       |  6 +++++-
> > > >    3 files changed, 12 insertions(+), 39 deletions(-)
> > > >
> > > > diff --git a/include/net/net.h b/include/net/net.h
> > > > index 36e5fab..7af3e15 100644
> > > > --- a/include/net/net.h
> > > > +++ b/include/net/net.h
> > > > @@ -152,11 +152,6 @@ void qemu_check_nic_model(NICInfo *nd, const
> > > > char *model);
> > > >    int qemu_find_nic_model(NICInfo *nd, const char * const *models,
> > > >                            const char *default_model);
> > > >
> > > > -ssize_t qemu_deliver_packet(NetClientState *sender,
> > > > -                            unsigned flags,
> > > > -                            const uint8_t *data,
> > > > -                            size_t size,
> > > > -                            void *opaque);
> > > >    ssize_t qemu_deliver_packet_iov(NetClientState *sender,
> > > >                                unsigned flags,
> > > >                                const struct iovec *iov,
> > > > diff --git a/net/net.c b/net/net.c
> > > > index ad37419..ca35b27 100644
> > > > --- a/net/net.c
> > > > +++ b/net/net.c
> > > > @@ -597,36 +597,6 @@ static ssize_t filter_receive(NetClientState
> > > > *nc, NetFilterChain chain,
> > > >        return filter_receive_iov(nc, chain, sender, flags, &iov, 1,
> > > > sent_cb);
> > > >    }
> > > >
> > > > -ssize_t qemu_deliver_packet(NetClientState *sender,
> > > > -                            unsigned flags,
> > > > -                            const uint8_t *data,
> > > > -                            size_t size,
> > > > -                            void *opaque)
> > > > -{
> > > > -    NetClientState *nc = opaque;
> > > > -    ssize_t ret;
> > > > -
> > > > -    if (nc->link_down) {
> > > > -        return size;
> > > > -    }
> > > > -
> > > > -    if (nc->receive_disabled) {
> > > > -        return 0;
> > > > -    }
> > > > -
> > > > -    if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) {
> > > > -        ret = nc->info->receive_raw(nc, data, size);
> > > > -    } else {
> > > > -        ret = nc->info->receive(nc, data, size);
> > > > -    }
> > > > -
> > > > -    if (ret == 0) {
> > > > -        nc->receive_disabled = 1;
> > > > -    }
> > > > -
> > > > -    return ret;
> > > > -}
> > > > -
> > > >    void qemu_purge_queued_packets(NetClientState *nc)
> > > >    {
> > > >        if (!nc->peer) {
> > > > @@ -717,14 +687,18 @@ ssize_t qemu_send_packet_raw(NetClientState
> > > > *nc, const uint8_t *buf, int size)
> > > >    }
> > > >
> > > >    static ssize_t nc_sendv_compat(NetClientState *nc, const struct
> > > > iovec *iov,
> > > > -                               int iovcnt)
> > > > +                               int iovcnt, unsigned flags)
> > > >    {
> > > >        uint8_t buffer[NET_BUFSIZE];
> > > >        size_t offset;
> > > >
> > > >        offset = iov_to_buf(iov, iovcnt, 0, buffer, sizeof(buffer));
> > > >
> > > > -    return nc->info->receive(nc, buffer, offset);
> > > > +    if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) {
> > > > +        return nc->info->receive_raw(nc, buffer, offset);
> > > > +    } else {
> > > > +        return nc->info->receive(nc, buffer, offset);
> > > > +    }
> > >
> > > Then for net clients that doesn't support receive_iov, an extra memcpy
> > > is introduced. This seems unnecessary. And this patch looks independent,
> > > so please drop this patch from the series (This can also help to reduce
> > > the iteration). I think we may need this after all net clients support
> > > receive_iov().
> >
> > This patch is required by the next patch which introduce a
> > +/* Returns:
> > + *   >0 - success
> > + *    0 - queue packet for future redelivery
> > + *   <0 - failure (discard packet)
> > + */
> > +typedef ssize_t (NetQueueDeliverFunc)(NetClientState *sender,
> > +                                      unsigned flags,
> > +                                      const struct iovec *iov,
> > +                                      int iovcnt,
> > +                                      void *opaque);
> >
> > If we drop this patch, we will need to introduce 2 deliver func, which
> > seems not clean and simple.
>
> Then you can probably skip the iov_to_buf() if iov_cnt is one in the
> above code?

Seems like a good idea to avoid the extra memcpy, thank you! BTW,
can I do this on top of the series if there's no other comments?
so that the first 10 patch can be merged as is. if not, I will send another
version v12 to fix this.

> > > >    }
> > > >
> > > >    ssize_t qemu_deliver_packet_iov(NetClientState *sender,
> > > > @@ -747,7 +721,7 @@ ssize_t qemu_deliver_packet_iov(NetClientState
> > > > *sender,
> > > >        if (nc->info->receive_iov) {
> > > >            ret = nc->info->receive_iov(nc, iov, iovcnt);
> > > >        } else {
> > > > -        ret = nc_sendv_compat(nc, iov, iovcnt);
> > > > +        ret = nc_sendv_compat(nc, iov, iovcnt, flags);
> > > >        }
> > > >
> > > >        if (ret == 0) {
> > > > diff --git a/net/queue.c b/net/queue.c
> > > > index ebbe2bb..cf8db3a 100644
> > > > --- a/net/queue.c
> > > > +++ b/net/queue.c
> > > > @@ -152,9 +152,13 @@ static ssize_t qemu_net_queue_deliver(NetQueue
> > > > *queue,
> > > >                                          size_t size)
> > > >    {
> > > >        ssize_t ret = -1;
> > > > +    struct iovec iov = {
> > > > +        .iov_base = (void *)data,
> > > > +        .iov_len = size
> > > > +    };
> > > >
> > > >        queue->delivering = 1;
> > > > -    ret = qemu_deliver_packet(sender, flags, data, size,
> > > > queue->opaque);
> > > > +    ret = qemu_deliver_packet_iov(sender, flags, &iov, 1,
> > > > queue->opaque);
> > > >        queue->delivering = 0;
> > > >
> > > >        return ret;
> > >
> > >
> > > .
>
> .

--
Thanks,
Yang.