bonding: documentation and code cleanup for resend_igmp

Improves the documentation about how IGMP resend parameter
works, fix two missing checks and coding style issues.

Signed-off-by: Flavio Leitner <fbl@redhat.com>
Acked-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 23 insertions, 12 deletions

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 1f45bd887d65..675612ff41ae 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -770,8 +770,17 @@ resend_igmp
         a failover event. One membership report is issued immediately after
         the failover, subsequent packets are sent in each 200ms interval.
 
-        The valid range is 0 - 255; the default value is 1. This option
-        was added for bonding version 3.7.0.
+        The valid range is 0 - 255; the default value is 1. A value of 0
+        prevents the IGMP membership report from being issued in response
+        to the failover event.
+
+        This option is useful for bonding modes balance-rr (0), active-backup
+        (1), balance-tlb (5) and balance-alb (6), in which a failover can
+        switch the IGMP traffic from one slave to another.  Therefore a fresh
+        IGMP report must be issued to cause the switch to forward the incoming
+        IGMP traffic over the newly selected slave.
+
+        This option was added for bonding version 3.7.0.
 
 3. Configuring Bonding Devices
 ==============================
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 9ec4a505a79f..6141667c5fb7 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -852,7 +852,7 @@ static void bond_resend_igmp_join_requests(struct bonding *bond)
 static void bond_resend_igmp_join_requests_delayed(struct work_struct *work)
 {
         struct bonding *bond = container_of(work, struct bonding,
-                                                        mcast_work.work);
+                                            mcast_work.work);
         bond_resend_igmp_join_requests(bond);
 }
 
@@ -1172,10 +1172,12 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
         }
 
         /* resend IGMP joins since active slave has changed or
-         * all were sent on curr_active_slave */
-        if (((USES_PRIMARY(bond->params.mode) && new_active) ||
-             bond->params.mode == BOND_MODE_ROUNDROBIN) &&
-            netif_running(bond->dev)) {
+         * all were sent on curr_active_slave.
+         * resend only if bond is brought up with the affected
+         * bonding modes and the retransmission is enabled */
+        if (netif_running(bond->dev) && (bond->params.resend_igmp > 0) &&
+            ((USES_PRIMARY(bond->params.mode) && new_active) ||
+             bond->params.mode == BOND_MODE_ROUNDROBIN)) {
                 bond->igmp_retrans = bond->params.resend_igmp;
                 queue_delayed_work(bond->wq, &bond->mcast_work, 0);
         }
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index bb1319f9f173..88fcb25e554a 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1533,8 +1533,8 @@ static DEVICE_ATTR(all_slaves_active, S_IRUGO | S_IWUSR,
  * Show and set the number of IGMP membership reports to send on link failure
  */
 static ssize_t bonding_show_resend_igmp(struct device *d,
-                                         struct device_attribute *attr,
-                                         char *buf)
+                                        struct device_attribute *attr,
+                                        char *buf)
 {
         struct bonding *bond = to_bond(d);
 
@@ -1542,8 +1542,8 @@ static ssize_t bonding_show_resend_igmp(struct device *d,
 }
 
 static ssize_t bonding_store_resend_igmp(struct device *d,
-                                          struct device_attribute *attr,
-                                          const char *buf, size_t count)
+                                         struct device_attribute *attr,
+                                         const char *buf, size_t count)
 {
         int new_value, ret = count;
         struct bonding *bond = to_bond(d);
@@ -1555,7 +1555,7 @@ static ssize_t bonding_store_resend_igmp(struct device *d,
                 goto out;
         }
 
-        if (new_value < 0) {
+        if (new_value < 0 || new_value > 255) {
                 pr_err("%s: Invalid resend_igmp value %d not in range 0-255; rejected.\n",
                        bond->dev->name, new_value);
                 ret = -EINVAL;