[3.16.y-ckt stable] Patch "IB/mlx4: Saturate RoCE port PMA counters in case of overflow" has been added to staging queue

[Luis Henriques]

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

    IB/mlx4: Saturate RoCE port PMA counters in case of overflow

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt10.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 474943c5ebb6dca13689dc08ee8147410f8b9732 Mon Sep 17 00:00:00 2001
From: Majd Dibbiny <majd at mellanox.com>
Date: Wed, 18 Mar 2015 16:51:37 +0200
Subject: IB/mlx4: Saturate RoCE port PMA counters in case of overflow

commit 61a3855bb726cbb062ef02a31a832dea455456e0 upstream.

For RoCE ports, we set the u32 PMA values based on u64 HCA counters. In case of
overflow, according to the IB spec, we have to saturate a counter to its
max value, do that.

Fixes: c37791349cc7 ('IB/mlx4: Support PMA counters for IBoE')
Signed-off-by: Majd Dibbiny <majd at mellanox.com>
Signed-off-by: Eran Ben Elisha <eranbe at mellanox.com>
Signed-off-by: Hadar Hen Zion <hadarh at mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz at mellanox.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/infiniband/hw/mlx4/mad.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/hw/mlx4/mad.c b/drivers/infiniband/hw/mlx4/mad.c
index 287ad0564acd..c128abd5f4c2 100644
--- a/drivers/infiniband/hw/mlx4/mad.c
+++ b/drivers/infiniband/hw/mlx4/mad.c
@@ -64,6 +64,14 @@ enum {
 #define GUID_TBL_BLK_NUM_ENTRIES 8
 #define GUID_TBL_BLK_SIZE (GUID_TBL_ENTRY_SIZE * GUID_TBL_BLK_NUM_ENTRIES)

+/* Counters should be saturate once they reach their maximum value */
+#define ASSIGN_32BIT_COUNTER(counter, value) do {\
+	if ((value) > U32_MAX)			 \
+		counter = cpu_to_be32(U32_MAX); \
+	else					 \
+		counter = cpu_to_be32(value);	 \
+} while (0)
+
 struct mlx4_mad_rcv_buf {
 	struct ib_grh grh;
 	u8 payload[256];
@@ -806,10 +814,14 @@ static int ib_process_mad(struct ib_device *ibdev, int mad_flags, u8 port_num,
 static void edit_counter(struct mlx4_counter *cnt,
 					struct ib_pma_portcounters *pma_cnt)
 {
-	pma_cnt->port_xmit_data = cpu_to_be32((be64_to_cpu(cnt->tx_bytes)>>2));
-	pma_cnt->port_rcv_data  = cpu_to_be32((be64_to_cpu(cnt->rx_bytes)>>2));
-	pma_cnt->port_xmit_packets = cpu_to_be32(be64_to_cpu(cnt->tx_frames));
-	pma_cnt->port_rcv_packets  = cpu_to_be32(be64_to_cpu(cnt->rx_frames));
+	ASSIGN_32BIT_COUNTER(pma_cnt->port_xmit_data,
+			     (be64_to_cpu(cnt->tx_bytes) >> 2));
+	ASSIGN_32BIT_COUNTER(pma_cnt->port_rcv_data,
+			     (be64_to_cpu(cnt->rx_bytes) >> 2));
+	ASSIGN_32BIT_COUNTER(pma_cnt->port_xmit_packets,
+			     be64_to_cpu(cnt->tx_frames));
+	ASSIGN_32BIT_COUNTER(pma_cnt->port_rcv_packets,
+			     be64_to_cpu(cnt->rx_frames));
 }

 static int iboe_process_mad(struct ib_device *ibdev, int mad_flags, u8 port_num,