Patch "s390/qeth: fix thinko in IPv4 multicast address tracking" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    s390/qeth: fix thinko in IPv4 multicast address tracking

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-qeth-fix-thinko-in-ipv4-multicast-address-tracking.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Dec 14 11:45:40 CET 2017
From: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Date: Fri, 1 Dec 2017 10:14:49 +0100
Subject: s390/qeth: fix thinko in IPv4 multicast address tracking

From: Julian Wiedmann <jwi@linux.vnet.ibm.com>


[ Upsteam commit bc3ab70584696cb798b9e1e0ac8e6ced5fd4c3b8 ]

Commit 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback")
reworked how secondary addresses are managed for qeth devices.
Instead of dropping & subsequently re-adding all addresses on every
ndo_set_rx_mode() call, qeth now keeps track of the addresses that are
currently registered with the HW.
On a ndo_set_rx_mode(), we thus only need to do (de-)registration
requests for the addresses that have actually changed.

On L3 devices, the lookup for IPv4 Multicast addresses checks the wrong
hashtable - and thus never finds a match. As a result, we first delete
*all* such addresses, and then re-add them again. So each set_rx_mode()
causes a short period where the IPv4 Multicast addresses are not
registered, and the card stops forwarding inbound traffic for them.

Fix this by setting the ->is_multicast flag on the lookup object, thus
enabling qeth_l3_ip_from_hash() to search the correct hashtable and
find a match there.

Fixes: 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback")
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/s390/net/qeth_l3_main.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -1376,6 +1376,7 @@ qeth_l3_add_mc_to_hash(struct qeth_card
 
 		tmp->u.a4.addr = be32_to_cpu(im4->multiaddr);
 		memcpy(tmp->mac, buf, sizeof(tmp->mac));
+		tmp->is_multicast = 1;
 
 		ipm = qeth_l3_ip_from_hash(card, tmp);
 		if (ipm) {


Patches currently in stable-queue which might be from jwi@linux.vnet.ibm.com are

queue-4.14/s390-qeth-fix-thinko-in-ipv4-multicast-address-tracking.patch
queue-4.14/s390-qeth-fix-gso-throughput-regression.patch
queue-4.14/s390-qeth-fix-early-exit-from-error-path.patch
queue-4.14/s390-qeth-build-max-size-gso-skbs-on-l2-devices.patch