On 2014/2/24 21:29, Michael S. Tsirkin wrote:
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@xxxxxxxxxx>
Do you actually observe guest hang?
yes, guest nic could not xmit any more until the skb holded by host has
been freed, the mainly reason is that though virtio-net could use vring
desc out of order, but ubufs is been used by vhost in order. so only
one skb could cause guest nic hang.
I would expect orphan frags in
__netif_receive_skb_core to be enough.
yes, it would be better. I would deliver another patch soon.
---
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
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