[4.2.y-ckt stable] Patch "net/mlx4_core: Do not BUG_ON during reset when PCI is offline" 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_core: Do not BUG_ON during reset when PCI is offline

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-ckt5.

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 c0a90ab0924711a5167e8477279009c300dbf2ec Mon Sep 17 00:00:00 2001
From: Daniel Jurgens <danielj at mellanox.com>
Date: Wed, 17 Feb 2016 17:24:25 +0200
Subject: net/mlx4_core: Do not BUG_ON during reset when PCI is offline

commit 22e3817e6c8301dc0520b855c8a2d764580e719c upstream.

The PCI channel could go offline during reset due to EEH.  Don't bug on in
this case, the error is recoverable.

Fixes: f6bc11e42646 ('net/mlx4_core: Enhance the catas flow to support device reset')
Signed-off-by: Daniel Jurgens <danielj at mellanox.com>
Reviewed-by: Yishai Hadas <yishaih 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/catas.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/catas.c b/drivers/net/ethernet/mellanox/mlx4/catas.c
index 715de8a..c7e9399 100644
--- a/drivers/net/ethernet/mellanox/mlx4/catas.c
+++ b/drivers/net/ethernet/mellanox/mlx4/catas.c
@@ -182,10 +182,17 @@ void mlx4_enter_error_state(struct mlx4_dev_persistent *persist)
 		err = mlx4_reset_slave(dev);
 	else
 		err = mlx4_reset_master(dev);
-	BUG_ON(err != 0);

+	if (!err) {
+		mlx4_err(dev, "device was reset successfully\n");
+	} else {
+		/* EEH could have disabled the PCI channel during reset. That's
+		 * recoverable and the PCI error flow will handle it.
+		 */
+		if (!pci_channel_offline(dev->persist->pdev))
+			BUG_ON(1);
+	}
 	dev->persist->state |= MLX4_DEVICE_STATE_INTERNAL_ERROR;
-	mlx4_err(dev, "device was reset successfully\n");
 	mutex_unlock(&persist->device_state_mutex);

 	/* At that step HW was already reset, now notify clients */
--
2.7.0