Re: [Qemu-devel] [PATCH 2/3] net: Flush queues when runstate changes back to running

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Aug 14, 2014 at 02:13:57PM +0800, zhanghailiang wrote:
> When the runstate changes back to running, we definitely need to flush
> queues to get packets flowing again.
> 
> Here we implement this in the net layer:
> (1) add a member 'VMChangeStateEntry *vmstate' to struct NICState,
> Which will listen for VM runstate changes.
> (2) Register a handler function for VMstate change.
> When vm changes back to running, we flush all queues in the callback function.
> 
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>

Hmm looks like virtio patch will need to be squashed as well?

> ---
>  include/net/net.h |  1 +
>  net/net.c         | 26 ++++++++++++++++++++++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/include/net/net.h b/include/net/net.h
> index 312f728..a294277 100644
> --- a/include/net/net.h
> +++ b/include/net/net.h
> @@ -97,6 +97,7 @@ typedef struct NICState {
>      NICConf *conf;
>      void *opaque;
>      bool peer_deleted;
> +    VMChangeStateEntry *vmstate;
>  } NICState;
>  
>  NetClientState *qemu_find_netdev(const char *id);
> diff --git a/net/net.c b/net/net.c
> index 5bb2821..506e58f 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -242,6 +242,29 @@ NetClientState *qemu_new_net_client(NetClientInfo *info,
>      return nc;
>  }
>  
> +static void nic_vmstate_change_handler(void *opaque,
> +                                       int running,
> +                                       RunState state)
> +{
> +    NICState *nic = opaque;
> +    NetClientState *nc;
> +    int i, queues;
> +
> +    if (!running) {
> +        return;
> +    }
> +
> +    queues =  MAX(1, nic->conf->peers.queues);
> +    for (i = 0; i < queues; i++) {
> +        nc = &nic->ncs[i];
> +        if (nc->receive_disabled
> +            || (nc->info->can_receive && !nc->info->can_receive(nc))) {
> +            continue;
> +        }
> +        qemu_flush_queued_packets(nc);
> +    }
> +}
> +
>  NICState *qemu_new_nic(NetClientInfo *info,
>                         NICConf *conf,
>                         const char *model,
> @@ -259,6 +282,8 @@ NICState *qemu_new_nic(NetClientInfo *info,
>      nic->ncs = (void *)nic + info->size;
>      nic->conf = conf;
>      nic->opaque = opaque;
> +    nic->vmstate = qemu_add_vm_change_state_handler(nic_vmstate_change_handler,
> +                                                    nic);
>  
>      for (i = 0; i < queues; i++) {
>          qemu_net_client_setup(&nic->ncs[i], info, peers[i], model, name,
> @@ -379,6 +404,7 @@ void qemu_del_nic(NICState *nic)
>          qemu_free_net_client(nc);
>      }
>  
> +    qemu_del_vm_change_state_handler(nic->vmstate);
>      g_free(nic);
>  }
>  
> -- 
> 1.7.12.4
>