[4.2.y-ckt stable] Patch "net/mlx4_en: Fix HW timestamp init issue upon system startup" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

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

    net/mlx4_en: Fix HW timestamp init issue upon system startup

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt2.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 4ffc2fc554b9b711ccfeb1e4cf9549bd67a80aeb Mon Sep 17 00:00:00 2001
From: Eugenia Emantayev <eugenia at mellanox.com>
Date: Thu, 17 Dec 2015 15:35:38 +0200
Subject: net/mlx4_en: Fix HW timestamp init issue upon system startup

commit 90683061dd50b0d70f01466c2d694f4e928a86f3 upstream.

mlx4_en_init_timestamp was called before creation of netdev and port
init, thus used uninitialized values.  Specifically - NIC frequency was
incorrect causing wrong calculations and later wrong HW timestamps.

Fixes: 1ec4864b1017 ('net/mlx4_en: Fixed crash when port type is changed')
Signed-off-by: Eugenia Emantayev <eugenia at mellanox.com>
Signed-off-by: Marina Varshaver <marinav at mellanox.com>
Signed-off-by: Eran Ben Elisha <eranbe 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: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_clock.c  | 7 +++++++
 drivers/net/ethernet/mellanox/mlx4/en_main.c   | 7 -------
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 7 +++++++
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index 8a083d7..038f9ce 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -242,6 +242,13 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
 	unsigned long flags;
 	u64 ns, zero = 0;

+	/* mlx4_en_init_timestamp is called for each netdev.
+	 * mdev->ptp_clock is common for all ports, skip initialization if
+	 * was done for other port.
+	 */
+	if (mdev->ptp_clock)
+		return;
+
 	rwlock_init(&mdev->clock_lock);

 	memset(&mdev->cycles, 0, sizeof(mdev->cycles));
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_main.c b/drivers/net/ethernet/mellanox/mlx4/en_main.c
index 913b716..24cec68 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_main.c
@@ -210,9 +210,6 @@ static void mlx4_en_remove(struct mlx4_dev *dev, void *endev_ptr)
 		if (mdev->pndev[i])
 			mlx4_en_destroy_netdev(mdev->pndev[i]);

-	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_TS)
-		mlx4_en_remove_timestamp(mdev);
-
 	flush_workqueue(mdev->workqueue);
 	destroy_workqueue(mdev->workqueue);
 	(void) mlx4_mr_free(dev, &mdev->mr);
@@ -278,10 +275,6 @@ static void *mlx4_en_add(struct mlx4_dev *dev)
 	mlx4_foreach_port(i, dev, MLX4_PORT_TYPE_ETH)
 		mdev->port_cnt++;

-	/* Initialize time stamp mechanism */
-	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_TS)
-		mlx4_en_init_timestamp(mdev);
-
 	/* Set default number of RX rings*/
 	mlx4_en_set_num_rx_rings(mdev);

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index b32514d..8544af0 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2056,6 +2056,9 @@ void mlx4_en_destroy_netdev(struct net_device *dev)
 	/* flush any pending task for this netdev */
 	flush_workqueue(mdev->workqueue);

+	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_TS)
+		mlx4_en_remove_timestamp(mdev);
+
 	/* Detach the netdev so tasks would not attempt to access it */
 	mutex_lock(&mdev->state_lock);
 	mdev->pndev[priv->port] = NULL;
@@ -2997,6 +3000,10 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 	}
 	queue_delayed_work(mdev->workqueue, &priv->stats_task, STATS_DELAY);

+	/* Initialize time stamp mechanism */
+	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_TS)
+		mlx4_en_init_timestamp(mdev);
+
 	queue_delayed_work(mdev->workqueue, &priv->service_task,
 			   SERVICE_TASK_DELAY);

--
1.9.1