Subject: Re: [PATCH 1/1] bonding: restrict up state in 802.3ad mode

From: Jay Vosburgh <[email-masked]>
Date: Thu, 17 Dec 2015 13:57:16 -0800

<[email-masked]> wrote:

>From: Zhu Yanjun <[email-masked]>
>
>In 802.3ad mode, the speed and duplex is needed. But in some NIC,
>there is a time span between NIC up state and getting speed and duplex.
>As such, sometimes a slave in 802.3ad mode is in up state without
>speed and duplex. This will make bonding in 802.3ad mode can not
>work well. 
>To make bonding driver be compatible with more NICs, it is
>necessary to restrict the up state in 802.3ad mode.

	What device is this?  It seems a bit odd that an Ethernet device
can be carrier up but not have the duplex and speed available.

	Also, what are the option settings for bonding?  Specifically,
is "use_carrier" set to 0?  The default setting is 1.

	In general, though, bonding expects a speed or duplex change to
be announced via a NETDEV_UPDATE or NETDEV_UP notifier, which would
propagate to the 802.3ad logic.

	If the device here is going carrier up prior to having speed or
duplex available, then maybe it should call netdev_state_change() when
the duplex and speed are available, or delay calling netif_carrier_on().

>Signed-off-by: Zhu Yanjun <[email-masked]>
>---
> drivers/net/bonding/bond_main.c |   19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 9e0f8a7..0a80fb3 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -1991,6 +1991,25 @@ static int bond_miimon_inspect(struct bonding *bond)
> 
> 		link_state = bond_check_dev_link(bond, slave->dev, 0);
> 
>+		/* Since some NIC has time span between netif_running and
>+		 * getting speed and duples. That is, after a NIC is up (netif_running),
>+		 * there is a time span before this NIC is negotiated with speed and duplex.
>+		 * During this time span, the slave in 802.3ad is configured without speed
>+		 * and duplex. This 802.3ad bonding will not work because it needs slave's speed
>+		 * and duplex to generate key field.
>+		 * As such, we restrict up in 802.3ad mode to: netif_running && peed != SPEED_UNKNOWN &&
>+		 * duplex != DUPLEX_UNKNOWN
>+		 */
>+		if ((BMSR_LSTATUS == link_state) &&
>+		    (BOND_MODE(bond) == BOND_MODE_8023AD)) {
>+			bond_update_speed_duplex(slave);
>+			if ((slave->speed == SPEED_UNKNOWN) ||
>+			    (slave->duplex == DUPLEX_UNKNOWN)) {
>+				link_state = 0;
>+				netdev_info(bond->dev, "In 802.3ad mode, it is not enough to up without speed and duplex");
>+			}
>+		}

	Also, as a functional note on this patch, the above looks like
it will spam the log repeatedly every miimon interval for as long as the
"carrier up but no speed/duplex" situation persists.

	-J

> 		switch (slave->link) {
> 		case BOND_LINK_UP:
> 			if (link_state)
>-- 
>1.7.9.5

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