5 files changed, 51 insertions, 2 deletions

diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index 77da2e849623..a047eb973e3b 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -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)) {
+                                netif_carrier_off(bond->dev);
+                                return 1;
+                        }
+                } else if (!netif_carrier_ok(bond->dev)) {
                         netif_carrier_on(bond->dev);
                         return 1;
                 }
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);
diff --git a/drivers/net/bonding/bond_procfs.c b/drivers/net/bonding/bond_procfs.c
index c97307ddd1c9..95de93b90386 100644
--- a/drivers/net/bonding/bond_procfs.c
+++ b/drivers/net/bonding/bond_procfs.c
@@ -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",
                            ad_select_tbl[bond->params.ad_select].modename);
 
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 03d1196b844d..b60835f58650 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -819,6 +819,38 @@ out:
 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[] = {
         &dev_attr_queue_id.attr,
         &dev_attr_all_slaves_active.attr,
         &dev_attr_resend_igmp.attr,
+        &dev_attr_min_links.attr,
         NULL,
 };
 
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 382903f0562e..2936171f5332 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -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;