Re: [Qemu-devel] [QEMU] net: adapt dump to support the new syntax

[Paolo Bonzini]

Il 17/05/2012 07:59, Zhi Yong Wu ha scritto:
>> > However, then I noticed that qemu_can_send_packet is not called very much,
>> > and I do not understand why qemu_net_queue_send and qemu_net_queue_send_iov
>> > do not call qemu_can_send_packet before calling deliver/deliver_iov.
> This case has existed in current upstream code, not only vlan-hub
> code. Currently can_send function has been called by backend send
> function before deliver/deliver_iov, If we put can_send in queue send
> function, your idea will have a big challenge for slirp packet queue.

Exactly why?  For SLIRP's receive path, SLIRP doesn't implement
can_receive at all so it will never block.  For the send path, when flow
control kicks qemu_net_queue_append will copy the packet so it is not a
problem for SLIRP's stack-allocated packets.

> We can implement your idea below later, not in this patchset. What do
> you think?

Note that my idea above was only means to an end.  If you can remove the
TODOs in a convincing manner, that would be fine.

Paolo