Re: [Qemu-devel] [PATCH] net: synchronize net_host_device_remove with host_net_remove_completion

[Stefan Hajnoczi]

On Mon, Jan 19, 2015 at 12:27:11PM +0100, Paolo Bonzini wrote:
> On 02/01/2015 17:20, Paolo Bonzini wrote:
> >> > 
> >> > The assert can be dropped completely since the code already has an
> >> > equivalent assert:
> >> > 
> >> >   queues = qemu_find_net_clients_except(nc->name, ncs,
> >> >                                         NET_CLIENT_OPTIONS_KIND_NIC,
> >> >                                         MAX_QUEUE_NUM);
> >> >   assert(queues != 0); <-- fail if type == NET_CLIENT_OPTIONS_KIND_NIC
> > I left it on purpose for documentation, but I'll send v2 next week that
> > removes it.
> 
> Actually it's not the same.  If you have "-netdev user,id=e1000 -device
> e1000,netdev=e1000" you will be able to call qemu_del_net_client on the
> NIC, and it will _not_ fail if the assertion is removed.

I don't follow.

If you call qemu_del_net_client(e1000_nic) then
qemu_find_net_clients_except(nc->name, ncs, NET_CLIENT_OPTIONS_KIND_NIC,
MAX_QUEUE_NUM) returns 0.  This causes the assert(queues != 0) to fail.

Can you explain the scenario?

Stefan

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