hv_netvsc: Fix a network regression after ifdown/ifup

debian/changelog

@@ -291,6 +291,9 @@ linux (4.16.13-1) UNRELEASED; urgency=medium
   [ Ben Hutchings ]
   * ext4: Fix duplicate softdep fields in module info
 
+  [ Bastian Blank ]
+  * hv_netvsc: Fix a network regression after ifdown/ifup
+
  -- Salvatore Bonaccorso <carnil@debian.org>  Wed, 30 May 2018 08:41:30 +0200
 
 linux (4.16.12-1) unstable; urgency=medium

debian/patches/bugfix/all/hv_netvsc-Fix-a-network-regression-after-ifdown-ifup.patch

@@ -0,0 +1,43 @@
+From 52acf73b6e9a6962045feb2ba5a8921da2201915 Mon Sep 17 00:00:00 2001
+From: Dexuan Cui <decui@microsoft.com>
+Date: Wed, 6 Jun 2018 21:32:51 +0000
+Subject: [PATCH] hv_netvsc: Fix a network regression after ifdown/ifup
+
+Recently people reported the NIC stops working after
+"ifdown eth0; ifup eth0". It turns out in this case the TX queues are not
+enabled, after the refactoring of the common detach logic: when the NIC
+has sub-channels, usually we enable all the TX queues after all
+sub-channels are set up: see rndis_set_subchannel() ->
+netif_device_attach(), but in the case of "ifdown eth0; ifup eth0" where
+the number of channels doesn't change, we also must make sure the TX queues
+are enabled. The patch fixes the regression.
+
+Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
+Signed-off-by: Dexuan Cui <decui@microsoft.com>
+Cc: Stephen Hemminger <sthemmin@microsoft.com>
+Cc: K. Y. Srinivasan <kys@microsoft.com>
+Cc: Haiyang Zhang <haiyangz@microsoft.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/hyperv/netvsc_drv.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
+index bef4d55a108c..8eec156418ea 100644
+--- a/drivers/net/hyperv/netvsc_drv.c
++++ b/drivers/net/hyperv/netvsc_drv.c
+@@ -127,8 +127,10 @@ static int netvsc_open(struct net_device *net)
+ 	}
+ 
+ 	rdev = nvdev->extension;
+-	if (!rdev->link_state)
++	if (!rdev->link_state) {
+ 		netif_carrier_on(net);
++		netif_tx_wake_all_queues(net);
++	}
+ 
+ 	if (vf_netdev) {
+ 		/* Setting synthetic device up transparently sets
+-- 
+2.17.1
+

debian/patches/series

@@ -99,6 +99,7 @@ bugfix/all/partially-revert-usb-kconfig-using-select-for-usb_co.patch
 bugfix/all/kbuild-include-addtree-remove-quotes-before-matching-path.patch
 debian/revert-objtool-fix-config_stack_validation-y-warning.patch
 bugfix/all/i40e-build-for-64-bit-targets-only.patch
+bugfix/all/hv_netvsc-Fix-a-network-regression-after-ifdown-ifup.patch
 
 # Miscellaneous features
 features/all/kbuild-use-fmacro-prefix-map-to-make-__file__-a-rela.patch