bonding: add min links parameter to 802.3ad

This adds support for a configuring the minimum number of links that
must be active before asserting carrier. It is similar to the Cisco
EtherChannel min-links feature. This allows setting the minimum number
of member ports that must be up (link-up state) before marking the
bond device as up (carrier on). This is useful for situations where
higher level services such as clustering want to ensure a minimum
number of low bandwidth links are active before switchover.

See:
   http://bugzilla.vyatta.com/show_bug.cgi?id=7196

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index ebb1d219b45c..61265f74ed3d 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -98,6 +98,7 @@ static char *mode;
 static char *primary;
 static char *primary_reselect;
 static char *lacp_rate;
+static int min_links;
 static char *ad_select;
 static char *xmit_hash_policy;
 static int arp_interval = BOND_LINK_ARP_INTERV;
@@ -150,6 +151,9 @@ module_param(ad_select, charp, 0);
 MODULE_PARM_DESC(ad_select, "803.ad aggregation selection logic; "
                             "0 for stable (default), 1 for bandwidth, "
                             "2 for count");
+module_param(min_links, int, 0);
+MODULE_PARM_DESC(min_links, "Minimum number of available links before turning on carrier");
+
 module_param(xmit_hash_policy, charp, 0);
 MODULE_PARM_DESC(xmit_hash_policy, "balance-xor and 802.3ad hashing method; "
                                    "0 for layer 2 (default), 1 for layer 3+4, "
@@ -4798,6 +4802,7 @@ static int bond_check_params(struct bond_params *params)
         params->tx_queues = tx_queues;
         params->all_slaves_active = all_slaves_active;
         params->resend_igmp = resend_igmp;
+        params->min_links = min_links;
 
         if (primary) {
                 strncpy(params->primary, primary, IFNAMSIZ);