Re: [PATCH] bridge: orphan frags on local receive

Michael S. Tsirkin
2014-02-24T13:29:26Z

On Mon, Feb 24, 2014 at 09:12:20PM +0800, Qin Chuanyu wrote:
> with vhost tx zero_copy, guest nic might get hang when host reserving
> skb in socket queue delivered by guest, the case has been solved in
> tun, it also been needed by bridge. This could easily happened when a
> LAST_ACK state tcp occuring between guest and host.
>
> Signed-off-by: Chuanyu Qin <qinchuanyu@huawei.com>

Do you actually observe guest hang?

I would expect orphan frags in
__netif_receive_skb_core to be enough.

> ---
> net/bridge/br_input.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index 28d5446..744e27a 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -117,6 +117,8 @@ int br_handle_frame_finish(struct sk_buff *skb)
> br->dev->stats.multicast++;
> } else if ((dst = __br_fdb_get(br, dest, vid)) &&
> dst->is_local) {
> + if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
> + goto drop;
> skb2 = skb;
> /* Do not forward the packet since it's local. */
> skb = NULL;
> @@ -136,6 +138,7 @@ int br_handle_frame_finish(struct sk_buff *skb)
> out:
> return 0;
> drop:
> + skb_tx_error(skb);
> kfree_skb(skb);
> goto out;
> }
> --
> 1.7.3.1.msysgit.0