[ 3.5.y.z extended stable ] Patch "bnx2x: fix occasional statistics off-by-4GB error" has been added to staging queue

[Luis Henriques]

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

    bnx2x: fix occasional statistics off-by-4GB error

to the linux-3.5.y-queue branch of the 3.5.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-3.5.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
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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>From a740ee382856a30bd25f097d4c80c026da4b50dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= <maze at google.com>
Date: Fri, 15 Mar 2013 11:56:17 +0000
Subject: [PATCH] bnx2x: fix occasional statistics off-by-4GB error
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit b009aac12cd0fe34293c68af8ac48b85be3bd858 upstream.

The UPDATE_QSTAT function introduced on February 15, 2012
in commit 1355b704b9ba "bnx2x: consistent statistics after
internal driver reload" incorrectly fails to handle overflow
during addition of the lower 32-bit field of a stat.

This bug is present since 3.4-rc1 and should thus be considered
a candidate for stable 3.4+ releases.

Google-Bug-Id: 8374428
Signed-off-by: Maciej Żenczykowski <maze at google.com>
Cc: Mintz Yuval <yuvalmin at broadcom.com>
Acked-by: Eilon Greenstein <eilong at broadcom.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h
index 93e689fd..c664a61 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h
@@ -451,8 +451,9 @@ struct bnx2x_fw_port_stats_old {

 #define UPDATE_QSTAT(s, t) \
 	do { \
-		qstats->t##_hi = qstats_old->t##_hi + le32_to_cpu(s.hi); \
 		qstats->t##_lo = qstats_old->t##_lo + le32_to_cpu(s.lo); \
+		qstats->t##_hi = qstats_old->t##_hi + le32_to_cpu(s.hi) \
+			+ ((qstats->t##_lo < qstats_old->t##_lo) ? 1 : 0); \
 	} while (0)

 #define UPDATE_QSTAT_OLD(f) \
--
1.8.1.2