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

From: Jay Vosburgh <[email-masked]>
Date: Tue, 20 Aug 2019 16:14:34 -0700

<[email-masked]> wrote:

>From: Sha Zhang <[email-masked]>
>
>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 <[email-masked]>
>---
> 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;
>+				}
>+			}

	I don't believe that testing duplex here is correct; is_enabled
is not controlled by duplex, but by carrier state.  Duplex does affect
whether or not a port is permitted to aggregate, but that's entirely
separate logic (the AD_PORT_LACP_ENABLED flag).

	Would it be better to call bond_3ad_handle_link_change() here,
instead of manually testing duplex and setting is_enabled?

	-J

> 			continue;
> 		case BOND_LINK_UP:
>-- 
>1.8.3.1

---
	-Jay Vosburgh, [email-masked]