[PATCH] bonding: force enable lacp port after link state recovery for 802.3ad

[<zhangsha.zhang@huawei.com>]

From: Sha Zhang <zhangsha.zhang@huawei.com>

After the commit 334031219a84 ("bonding/802.3ad: fix slave link
initialization transition states") merged,
the slave's link status will be changed to BOND_LINK_FAIL
from BOND_LINK_DOWN in the following scenario:
- Driver reports loss of carrier and
  bonding driver receives NETDEV_CHANGE notifier
- slave's duplex and speed is zerod and
  its port->is_enabled is cleard to 'false';
- Driver reports link recovery and
  bonding driver receives NETDEV_UP notifier;
- If speed/duplex getting failed here, the link status
  will be changed to BOND_LINK_FAIL;
- The MII monotor later recover the slave's speed/duplex
  and set link status to BOND_LINK_UP, but remains
  the 'port->is_enabled' to 'false'.

In this scenario, the lacp port will not be enabled even its speed
and duplex are valid. The bond will not send LACPDU's, and its
state is 'AD_STATE_DEFAULTED' forever. The simplest fix I think
is to force enable lacp after port slave speed check in
bond_miimon_commit. As enabled, the lacp port can run its state machine
normally after link recovery.

Signed-off-by: Sha Zhang <zhangsha.zhang@huawei.com>
---
 drivers/net/bonding/bond_main.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 931d9d9..379253a 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2194,6 +2194,7 @@ static void bond_miimon_commit(struct bonding *bond)
 {
 	struct list_head *iter;
 	struct slave *slave, *primary;
+	struct port *port;
 
 	bond_for_each_slave(bond, slave, iter) {
 		switch (slave->new_link) {
@@ -2205,8 +2206,13 @@ static void bond_miimon_commit(struct bonding *bond)
 			 * link status
 			 */
 			if (BOND_MODE(bond) == BOND_MODE_8023AD &&
-			    slave->link == BOND_LINK_UP)
+			    slave->link == BOND_LINK_UP) {
 				bond_3ad_adapter_speed_duplex_changed(slave);
+				if (slave->duplex == DUPLEX_FULL) {
+					port = &(SLAVE_AD_INFO(slave)->port);
+					port->is_enabled = true;
+				}
+			}
 			continue;
 
 		case BOND_LINK_UP:
-- 
1.8.3.1