From f0dc117abdfa9a0e96c3d013d836460ef3cd08c7 Mon Sep 17 00:00:00 2001 From: Eli Cohen Date: Wed, 3 Mar 2010 12:27:52 +0000 Subject: [PATCH] IPoIB: Fix TX queue lockup with mixed UD/CM traffic The IPoIB UD QP reports send completions to priv->send_cq, which is usually left unarmed; it only gets armed when the number of outstanding send requests reaches the size of the TX queue. This arming is done only in the send path for the UD QP. However, when sending CM packets, the net queue may be stopped for the same reasons but no measures are taken to recover the UD path from a lockup. Consider this scenario: a host sends high rate of both CM and UD packets, with a TX queue length of N. If at some time the number of outstanding UD packets is more than N/2 and the overall outstanding packets is N-1, and CM sends a packet (making the number of outstanding sends equal N), the TX queue will be stopped. When all the CM packets complete, the number of outstanding packets will still be higher than N/2 so the TX queue will not be restarted. Fix this by calling ib_req_notify_cq() when the queue is stopped in the CM path. Signed-off-by: Eli Cohen Signed-off-by: Roland Dreier --- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c index 83a7751c38d6..6e3cc865e369 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c @@ -752,6 +752,8 @@ void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_ if (++priv->tx_outstanding == ipoib_sendq_size) { ipoib_dbg(priv, "TX ring 0x%x full, stopping kernel net queue\n", tx->qp->qp_num); + if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP)) + ipoib_warn(priv, "request notify on send CQ failed\n"); netif_stop_queue(dev); } }