[PATCH 4.9 04/30] bonding: require speed/duplex only for 802.3ad, alb and tlb

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

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

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

From: Andreas Born <futur.andy@googlemail.com>

commit ad729bc9acfb7c47112964b4877ef5404578ed13 upstream.

The patch c4adfc822bf5 ("bonding: make speed, duplex setting consistent
with link state") puts the link state to down if
bond_update_speed_duplex() cannot retrieve speed and duplex settings.
Assumably the patch was written with 802.3ad mode in mind which relies
on link speed/duplex settings. For other modes like active-backup these
settings are not required. Thus, only for these other modes, this patch
reintroduces support for slaves that do not support reporting speed or
duplex such as wireless devices. This fixes the regression reported in
bug 196547 (https://bugzilla.kernel.org/show_bug.cgi?id=196547).

Fixes: c4adfc822bf5 ("bonding: make speed, duplex setting consistent
with link state")
Signed-off-by: Andreas Born <futur.andy@googlemail.com>
Acked-by: Mahesh Bandewar <maheshb@google.com>
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 |    6 ++++--
 include/net/bonding.h           |    5 +++++
 2 files changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1531,7 +1531,8 @@ int bond_enslave(struct net_device *bond
 	new_slave->delay = 0;
 	new_slave->link_failure_count = 0;
 
-	if (bond_update_speed_duplex(new_slave))
+	if (bond_update_speed_duplex(new_slave) &&
+	    bond_needs_speed_duplex(bond))
 		new_slave->link = BOND_LINK_DOWN;
 
 	new_slave->last_rx = jiffies -
@@ -2136,7 +2137,8 @@ static void bond_miimon_commit(struct bo
 			continue;
 
 		case BOND_LINK_UP:
-			if (bond_update_speed_duplex(slave)) {
+			if (bond_update_speed_duplex(slave) &&
+			    bond_needs_speed_duplex(bond)) {
 				slave->link = BOND_LINK_DOWN;
 				netdev_warn(bond->dev,
 					    "failed to get link speed/duplex for %s\n",
--- a/include/net/bonding.h
+++ b/include/net/bonding.h
@@ -277,6 +277,11 @@ static inline bool bond_is_lb(const stru
 	       BOND_MODE(bond) == BOND_MODE_ALB;
 }
 
+static inline bool bond_needs_speed_duplex(const struct bonding *bond)
+{
+	return BOND_MODE(bond) == BOND_MODE_8023AD || bond_is_lb(bond);
+}
+
 static inline bool bond_is_nondyn_tlb(const struct bonding *bond)
 {
 	return (BOND_MODE(bond) == BOND_MODE_TLB)  &&