Subject: Re: [PATCH 1/1] bonding: delay up state without speed and duplex in 802.3ad mode

From: Jay Vosburgh <[email-masked]>
Date: Thu, 17 Dec 2015 20:54:06 -0800

<[email-masked]> wrote:

>From: yzhu1 <[email-masked]>
>
>In 802.3ad mode, the speed and duplex is needed. But in some NICs,
>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 robust and compatible with more NICs, it is
>necessary to delay the up state without speed and duplex in 802.3ad
>mode.

	You misunderstood my comment.  What I meant is that the device
driver for the network device should change to either delay carrier up
or issue a second notifier when speed and duplex are available.  If the
driver doesn't handle duplex and speed notification properly, it will
likely have trouble with more than just bonding.

	You also didn't mention the identity of the network device that
requires this special handling.  Is the driver part of the linux kernel?

	-J

>Signed-off-by: yzhu1 <[email-masked]>
>---
> drivers/net/bonding/bond_main.c |   34 ++++++++++++++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 9e0f8a7..a1d8708 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -419,6 +419,35 @@ const char *bond_slave_link_status(s8 link)
> 	}
> }
> 
>+/* This function is to check the speed and duplex of a NIC.
>+ * Since the speed and duplex of a slave device are very
>+ * important to the bonding in the 802.3ad mode. As such,
>+ * it is necessary to check the speed and duplex of a slave
>+ * device in 802.3ad mode.
>+ *
>+ * speed != SPEED_UNKNOWN and duplex == DUPLEX_FULL  :  1
>+ *                                           others  :  0
>+ */
>+static int __check_speed_duplex(struct net_device *netdev)
>+{
>+	struct ethtool_cmd ecmd;
>+	u32 slave_speed = SPEED_UNKNOWN;
>+	int res;
>+
>+	res = __ethtool_get_settings(netdev, &ecmd);
>+	if (res < 0)
>+		return 0;
>+
>+	slave_speed = ethtool_cmd_speed(&ecmd);
>+	if (slave_speed == 0 || slave_speed == ((__u32) -1))
>+		return 0;
>+
>+	if (DUPLEX_FULL != ecmd.duplex)
>+		return 0;
>+
>+	return 1;
>+}
>+
> /* if <dev> supports MII link status reporting, check its link status.
>  *
>  * We either do MII/ETHTOOL ioctls, or check netif_carrier_ok(),
>@@ -445,6 +474,11 @@ static int bond_check_dev_link(struct bonding *bond,
> 	if (!reporting && !netif_running(slave_dev))
> 		return 0;
> 
>+	/* Check the speed and duplex of the slave device in 802.3ad mode. */
>+	if ((BOND_MODE(bond) == BOND_MODE_8023AD) &&
>+	   !__check_speed_duplex(slave_dev))
>+		return 0;
>+
> 	if (bond->params.use_carrier)
> 		return netif_carrier_ok(slave_dev) ? BMSR_LSTATUS : 0;
> 
>-- 
>1.7.9.5
>

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