[3.8.y.z extended stable] Patch "tg3: update rx_jumbo_pending ring param only when jumbo frames are enabled" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    tg3: update rx_jumbo_pending ring param only when jumbo frames are enabled

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.24.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 1464e05e425a6d1b0b73790dca767ce984466459 Mon Sep 17 00:00:00 2001
From: Ivan Vecera <ivecera at redhat.com>
Date: Thu, 17 Apr 2014 14:51:08 +0200
Subject: tg3: update rx_jumbo_pending ring param only when jumbo frames are
 enabled

commit ba67b510035141bd89b40bf65efa0a79834311ca upstream.

The patch fixes a problem with dropped jumbo frames after usage of
'ethtool -G ... rx'.

Scenario:
1. ip link set eth0 up
2. ethtool -G eth0 rx N # <- This zeroes rx-jumbo
3. ip link set mtu 9000 dev eth0

The ethtool command set rx_jumbo_pending to zero so any received jumbo
packets are dropped and you need to use 'ethtool -G eth0 rx-jumbo N'
to workaround the issue.
The patch changes the logic so rx_jumbo_pending value is changed only if
jumbo frames are enabled (MTU > 1500).

Signed-off-by: Ivan Vecera <ivecera at redhat.com>
Acked-by: Michael Chan <mchan at broadcom.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/ethernet/broadcom/tg3.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index d619517..40d8e23 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -11514,7 +11514,9 @@ static int tg3_set_ringparam(struct net_device *dev, struct ethtool_ringparam *e
 	if (tg3_flag(tp, MAX_RXPEND_64) &&
 	    tp->rx_pending > 63)
 		tp->rx_pending = 63;
-	tp->rx_jumbo_pending = ering->rx_jumbo_pending;
+
+	if (tg3_flag(tp, JUMBO_RING_ENABLE))
+		tp->rx_jumbo_pending = ering->rx_jumbo_pending;

 	for (i = 0; i < tp->irq_max; i++)
 		tp->napi[i].tx_pending = ering->tx_pending;
--
1.9.1