Commit 655f8919 authored by stephen hemminger's avatar stephen hemminger Committed by David S. Miller
Browse files

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.


Signed-off-by: default avatarStephen Hemminger <>
Signed-off-by: default avatarFlavio Leitner <>
Signed-off-by: default avatarAndy Gospodarek <>
Signed-off-by: default avatarDavid S. Miller <>
parent 56f8a75c
......@@ -2342,8 +2342,17 @@ void bond_3ad_handle_link_change(struct slave *slave, char link)
int bond_3ad_set_carrier(struct bonding *bond)
if (__get_active_agg(&(SLAVE_AD_INFO(bond->first_slave).aggregator))) {
if (!netif_carrier_ok(bond->dev)) {
struct aggregator *active;
active = __get_active_agg(&(SLAVE_AD_INFO(bond->first_slave).aggregator));
if (active) {
/* are enough slaves available to consider link up? */
if (active->num_of_ports < bond->params.min_links) {
if (netif_carrier_ok(bond->dev)) {
return 1;
} else if (!netif_carrier_ok(bond->dev)) {
return 1;
......@@ -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, " 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);
......@@ -125,6 +125,7 @@ static void bond_info_show_master(struct seq_file *seq)
seq_puts(seq, "\n802.3ad info\n");
seq_printf(seq, "LACP rate: %s\n",
(bond->params.lacp_fast) ? "fast" : "slow");
seq_printf(seq, "Min links: %d\n", bond->params.min_links);
seq_printf(seq, "Aggregator selection policy (ad_select): %s\n",
......@@ -819,6 +819,38 @@ static ssize_t bonding_store_lacp(struct device *d,
static DEVICE_ATTR(lacp_rate, S_IRUGO | S_IWUSR,
bonding_show_lacp, bonding_store_lacp);
static ssize_t bonding_show_min_links(struct device *d,
struct device_attribute *attr,
char *buf)
struct bonding *bond = to_bond(d);
return sprintf(buf, "%d\n", bond->params.min_links);
static ssize_t bonding_store_min_links(struct device *d,
struct device_attribute *attr,
const char *buf, size_t count)
struct bonding *bond = to_bond(d);
int ret;
unsigned int new_value;
ret = kstrtouint(buf, 0, &new_value);
if (ret < 0) {
pr_err("%s: Ignoring invalid min links value %s.\n",
bond->dev->name, buf);
return ret;
pr_info("%s: Setting min links value to %u\n",
bond->dev->name, new_value);
bond->params.min_links = new_value;
return count;
static DEVICE_ATTR(min_links, S_IRUGO | S_IWUSR,
bonding_show_min_links, bonding_store_min_links);
static ssize_t bonding_show_ad_select(struct device *d,
struct device_attribute *attr,
char *buf)
......@@ -1601,6 +1633,7 @@ static struct attribute *per_bond_attrs[] = {
......@@ -147,6 +147,7 @@ struct bond_params {
int updelay;
int downdelay;
int lacp_fast;
unsigned int min_links;
int ad_select;
char primary[IFNAMSIZ];
int primary_reselect;
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