[PATCH 3.18 09/24] bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave

From: Greg Kroah-Hartman
Date: Fri Apr 27 2018 - 11:33:42 EST

3.18-stable review patch. If anyone has any objections, please let me know.


From: Xin Long <lucien.xin@xxxxxxxxx>

[ Upstream commit ddea788c63094f7c483783265563dd5b50052e28 ]

After Commit 8a8efa22f51b ("bonding: sync netpoll code with bridge"), it
would set slave_dev npinfo in slave_enable_netpoll when enslaving a dev
if bond->dev->npinfo was set.

However now slave_dev npinfo is set with bond->dev->npinfo before calling
slave_enable_netpoll. With slave_dev npinfo set, __netpoll_setup called
in slave_enable_netpoll will not call slave dev's .ndo_netpoll_setup().
It causes that the lower dev of this slave dev can't set its npinfo.

One way to reproduce it:

# modprobe bonding
# brctl addbr br0
# brctl addif br0 eth1
# ifconfig bond0 up
# ifenslave bond0 eth2
# systemctl restart netconsole
# ifenslave bond0 br0
# ifconfig eth2 down
# systemctl restart netconsole

The netpoll won't really work.

This patch is to remove that slave_dev npinfo setting in bond_enslave().

Fixes: 8a8efa22f51b ("bonding: sync netpoll code with bridge")
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/net/bonding/bond_main.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1505,8 +1505,7 @@ int bond_enslave(struct net_device *bond
} /* switch(bond_mode) */

- slave_dev->npinfo = bond->dev->npinfo;
- if (slave_dev->npinfo) {
+ if (bond->dev->npinfo) {
if (slave_enable_netpoll(new_slave)) {
netdev_info(bond_dev, "master_dev is using netpoll, but new slave device does not support netpoll\n");
res = -EBUSY;