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>

1 files changed, 11 insertions, 2 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
 ==============================