[3.16.y-ckt stable] Patch "mlx4: Fix tx ring affinity_mask creation" has been added to staging queue

[Luis Henriques]

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

    mlx4: Fix tx ring affinity_mask creation

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/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt12.

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 0502c51a4a61b987a2ea4c7c60c3dee6c558bbdb Mon Sep 17 00:00:00 2001
From: Benjamin Poirier <bpoirier at suse.de>
Date: Tue, 28 Apr 2015 14:49:29 -0700
Subject: mlx4: Fix tx ring affinity_mask creation

commit 42eab005a5dd5d7ea2b0328aecc4d6cc0c23c9c2 upstream.

By default, the number of tx queues is limited by the number of online cpus
in mlx4_en_get_profile(). However, this limit no longer holds after the
ethtool .set_channels method has been called. In that situation, the driver
may access invalid bits of certain cpumask variables when queue_index >=
nr_cpu_ids.

Signed-off-by: Benjamin Poirier <bpoirier at suse.de>
Acked-by: Ido Shamay <idos at mellanox.com>
Fixes: d03a68f ("net/mlx4_en: Configure the XPS queue mapping on driver load")
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_tx.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 0610c85d4371..8068b0557c5a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -132,8 +132,10 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
 	ring->hwtstamp_tx_type = priv->hwtstamp_config.tx_type;
 	ring->queue_index = queue_index;

-	if (queue_index < priv->num_tx_rings_p_up && cpu_online(queue_index))
-		cpumask_set_cpu(queue_index, &ring->affinity_mask);
+	if (queue_index < priv->num_tx_rings_p_up)
+		cpumask_set_cpu_local_first(queue_index,
+					    priv->mdev->dev->numa_node,
+					    &ring->affinity_mask);

 	*pring = ring;
 	return 0;
@@ -200,7 +202,7 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,

 	err = mlx4_qp_to_ready(mdev->dev, &ring->wqres.mtt, &ring->context,
 			       &ring->qp, &ring->qp_state);
-	if (!user_prio && cpu_online(ring->queue_index))
+	if (!cpumask_empty(&ring->affinity_mask))
 		netif_set_xps_queue(priv->dev, &ring->affinity_mask,
 				    ring->queue_index);