Patch "net/mlx4_core: Avoid command timeouts during VF driver device shutdown" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    net/mlx4_core: Avoid command timeouts during VF driver device shutdown

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-mlx4_core-avoid-command-timeouts-during-vf-driver-device-shutdown.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Jun 15 13:06:48 CEST 2017
From: Jack Morgenstein <jackm@dev.mellanox.co.il>
Date: Mon, 30 Jan 2017 15:11:45 +0200
Subject: net/mlx4_core: Avoid command timeouts during VF driver device shutdown

From: Jack Morgenstein <jackm@dev.mellanox.co.il>


[ Upstream commit d585df1c5ccf995fcee910705ad7a9cdd11d4152 ]

Some Hypervisors detach VFs from VMs by instantly causing an FLR event
to be generated for a VF.

In the mlx4 case, this will cause that VF's comm channel to be disabled
before the VM has an opportunity to invoke the VF device's "shutdown"
method.

The result is that the VF driver on the VM will experience a command
timeout during the shutdown process when the Hypervisor does not deliver
a command-completion event to the VM.

To avoid FW command timeouts on the VM when the driver's shutdown method
is invoked, we detect the absence of the VF's comm channel at the very
start of the shutdown process. If the comm-channel has already been
disabled, we cause all FW commands during the device shutdown process to
immediately return success (and thus avoid all command timeouts).

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx4/catas.c |    2 +-
 drivers/net/ethernet/mellanox/mlx4/intf.c  |   12 ++++++++++++
 drivers/net/ethernet/mellanox/mlx4/mlx4.h  |    1 +
 3 files changed, 14 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx4/catas.c
+++ b/drivers/net/ethernet/mellanox/mlx4/catas.c
@@ -158,7 +158,7 @@ static int mlx4_reset_slave(struct mlx4_
 	return -ETIMEDOUT;
 }
 
-static int mlx4_comm_internal_err(u32 slave_read)
+int mlx4_comm_internal_err(u32 slave_read)
 {
 	return (u32)COMM_CHAN_EVENT_INTERNAL_ERR ==
 		(slave_read & (u32)COMM_CHAN_EVENT_INTERNAL_ERR) ? 1 : 0;
--- a/drivers/net/ethernet/mellanox/mlx4/intf.c
+++ b/drivers/net/ethernet/mellanox/mlx4/intf.c
@@ -222,6 +222,18 @@ void mlx4_unregister_device(struct mlx4_
 		return;
 
 	mlx4_stop_catas_poll(dev);
+	if (dev->persist->interface_state & MLX4_INTERFACE_STATE_DELETION &&
+	    mlx4_is_slave(dev)) {
+		/* In mlx4_remove_one on a VF */
+		u32 slave_read =
+			swab32(readl(&mlx4_priv(dev)->mfunc.comm->slave_read));
+
+		if (mlx4_comm_internal_err(slave_read)) {
+			mlx4_dbg(dev, "%s: comm channel is down, entering error state.\n",
+				 __func__);
+			mlx4_enter_error_state(dev->persist);
+		}
+	}
 	mutex_lock(&intf_mutex);
 
 	list_for_each_entry(intf, &intf_list, list)
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
@@ -1220,6 +1220,7 @@ void mlx4_qp_event(struct mlx4_dev *dev,
 void mlx4_srq_event(struct mlx4_dev *dev, u32 srqn, int event_type);
 
 void mlx4_enter_error_state(struct mlx4_dev_persistent *persist);
+int mlx4_comm_internal_err(u32 slave_read);
 
 int mlx4_SENSE_PORT(struct mlx4_dev *dev, int port,
 		    enum mlx4_port_type *type);


Patches currently in stable-queue which might be from jackm@dev.mellanox.co.il are

queue-4.9/net-mlx4_core-avoid-command-timeouts-during-vf-driver-device-shutdown.patch