[ 3.5.y.z extended stable ] Patch "sfc: lock TX queues when calling netif_device_detach()" has been added to staging queue

[Luis Henriques]

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

    sfc: lock TX queues when calling netif_device_detach()

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 90ea0a93789d55f63519808d0607dd2dee0141af Mon Sep 17 00:00:00 2001
From: Daniel Pieczko <dpieczko at solarflare.com>
Date: Wed, 17 Oct 2012 13:21:23 +0100
Subject: [PATCH] sfc: lock TX queues when calling netif_device_detach()

commit c2f3b8e3a44b6fe9e36704e30157ebe1a88c08b1 upstream.

The assertion of netif_device_present() at the top of
efx_hard_start_xmit() may fail if we don't do this.

Signed-off-by: Ben Hutchings <bhutchings at solarflare.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/sfc/efx.c      |  5 ++---
 drivers/net/ethernet/sfc/efx.h      | 13 +++++++++++++
 drivers/net/ethernet/sfc/selftest.c |  2 +-
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 16c4634..3d49f44 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -2224,7 +2224,7 @@ int efx_reset(struct efx_nic *efx, enum reset_type method)
 	netif_info(efx, drv, efx->net_dev, "resetting (%s)\n",
 		   RESET_TYPE(method));

-	netif_device_detach(efx->net_dev);
+	efx_device_detach_sync(efx);
 	efx_reset_down(efx, method);

 	rc = efx->type->reset(efx, method);
@@ -2718,8 +2718,7 @@ static int efx_pm_freeze(struct device *dev)
 	struct efx_nic *efx = pci_get_drvdata(to_pci_dev(dev));

 	efx->state = STATE_FINI;
-
-	netif_device_detach(efx->net_dev);
+	efx_device_detach_sync(efx);

 	efx_stop_all(efx);
 	efx_stop_interrupts(efx, false);
diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index 70755c9..320cf7b 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -162,4 +162,17 @@ extern void efx_link_status_changed(struct efx_nic *efx);
 extern void efx_link_set_advertising(struct efx_nic *efx, u32);
 extern void efx_link_set_wanted_fc(struct efx_nic *efx, u8);

+static inline void efx_device_detach_sync(struct efx_nic *efx)
+{
+	struct net_device *dev = efx->net_dev;
+
+	/* Lock/freeze all TX queues so that we can be sure the
+	 * TX scheduler is stopped when we're done and before
+	 * netif_device_present() becomes false.
+	 */
+	netif_tx_lock(dev);
+	netif_device_detach(dev);
+	netif_tx_unlock(dev);
+}
+
 #endif /* EFX_EFX_H */
diff --git a/drivers/net/ethernet/sfc/selftest.c b/drivers/net/ethernet/sfc/selftest.c
index 5f5b160..4a51ea3 100644
--- a/drivers/net/ethernet/sfc/selftest.c
+++ b/drivers/net/ethernet/sfc/selftest.c
@@ -721,7 +721,7 @@ int efx_selftest(struct efx_nic *efx, struct efx_self_tests *tests,
 	/* Detach the device so the kernel doesn't transmit during the
 	 * loopback test and the watchdog timeout doesn't fire.
 	 */
-	netif_device_detach(efx->net_dev);
+	efx_device_detach_sync(efx);

 	if (efx->type->test_chip) {
 		rc_reset = efx->type->test_chip(efx, tests);
--
1.8.1.2