Patchwork [3.5.y.z,extended,stable] Patch "IPoIB: Fix send lockup due to missed TX completion" has been added to staging queue

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Submitter Luis Henriques
Date April 1, 2013, 3:04 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/232756/
State New
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Luis Henriques - April 1, 2013, 3:04 p.m.
This is a note to let you know that I have just added a patch titled

    IPoIB: Fix send lockup due to missed TX completion

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see



From 63d853fceaaf095e01e2d4f3f11bf26f9a73be97 Mon Sep 17 00:00:00 2001
From: Mike Marciniszyn <>
Date: Tue, 26 Feb 2013 15:46:27 +0000
Subject: [PATCH] IPoIB: Fix send lockup due to missed TX completion

commit 1ee9e2aa7b31427303466776f455d43e5e3c9275 upstream.

Commit f0dc117abdfa ("IPoIB: Fix TX queue lockup with mixed UD/CM
traffic") attempts to solve an issue where unprocessed UD send
completions can deadlock the netdev.

The patch doesn't fully resolve the issue because if more than half
the tx_outstanding's were UD and all of the destinations are RC
reachable, arming the CQ doesn't solve the issue.

This patch uses the IB_CQ_REPORT_MISSED_EVENTS on the
ib_req_notify_cq().  If the rc is above 0, the UD send cq completion
callback is called directly to re-arm the send completion timer.

This issue is seen in very large parallel filesystem deployments
and the patch has been shown to correct the issue.

Reviewed-by: Dean Luick <>
Signed-off-by: Mike Marciniszyn <>
Signed-off-by: Roland Dreier <>
Signed-off-by: Luis Henriques <>
 drivers/infiniband/ulp/ipoib/ipoib_cm.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)



diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 014504d..3767853 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -755,9 +755,13 @@  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",
-			if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP))
-				ipoib_warn(priv, "request notify on send CQ failed\n");
+			rc = ib_req_notify_cq(priv->send_cq,
+			if (rc < 0)
+				ipoib_warn(priv, "request notify on send CQ failed\n");
+			else if (rc)
+				ipoib_send_comp_handler(priv->send_cq, dev);