[PATCH 4.9 03/30] bonding: fix active-backup transition

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

------------------

From: Mahesh Bandewar <maheshb@google.com>

commit 3f3c278c94dd994fe0d9f21679ae19b9c0a55292 upstream.

Earlier patch c4adfc822bf5 ("bonding: make speed, duplex setting
consistent with link state") made an attempt to keep slave state
consistent with speed and duplex settings. Unfortunately link-state
transition is used to change the active link especially when used
in conjunction with mii-mon. The above mentioned patch broke that
logic. Also when speed and duplex settings for a link are updated
during a link-event, the link-status should not be changed to
invoke correct transition logic.

This patch fixes this issue by moving the link-state update outside
of the bond_update_speed_duplex() fn and to the places where this fn
is called and update link-state selectively.

Fixes: c4adfc822bf5 ("bonding: make speed, duplex setting consistent
with link state")
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Reviewed-by: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Nate Clark <nate@neworld.us>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/bonding/bond_main.c |   13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -384,20 +384,15 @@ static int bond_update_speed_duplex(stru
 	slave->duplex = DUPLEX_UNKNOWN;
 
 	res = __ethtool_get_link_ksettings(slave_dev, &ecmd);
-	if (res < 0) {
-		slave->link = BOND_LINK_DOWN;
+	if (res < 0)
 		return 1;
-	}
-	if (ecmd.base.speed == 0 || ecmd.base.speed == ((__u32)-1)) {
-		slave->link = BOND_LINK_DOWN;
+	if (ecmd.base.speed == 0 || ecmd.base.speed == ((__u32)-1))
 		return 1;
-	}
 	switch (ecmd.base.duplex) {
 	case DUPLEX_FULL:
 	case DUPLEX_HALF:
 		break;
 	default:
-		slave->link = BOND_LINK_DOWN;
 		return 1;
 	}
 
@@ -1536,7 +1531,8 @@ int bond_enslave(struct net_device *bond
 	new_slave->delay = 0;
 	new_slave->link_failure_count = 0;
 
-	bond_update_speed_duplex(new_slave);
+	if (bond_update_speed_duplex(new_slave))
+		new_slave->link = BOND_LINK_DOWN;
 
 	new_slave->last_rx = jiffies -
 		(msecs_to_jiffies(bond->params.arp_interval) + 1);
@@ -2141,6 +2137,7 @@ static void bond_miimon_commit(struct bo
 
 		case BOND_LINK_UP:
 			if (bond_update_speed_duplex(slave)) {
+				slave->link = BOND_LINK_DOWN;
 				netdev_warn(bond->dev,
 					    "failed to get link speed/duplex for %s\n",
 					    slave->dev->name);