On Mon, Oct 04, 2010 at 09:24:10AM -0400, Andy Gospodarek wrote:

On Thu, Sep 30, 2010 at 05:45:24PM -0300, Flavio Leitner wrote:

quoted

It fixes bonding to rejoin multicast groups added
to VLAN devices on top of bonding when a failover
happens.

Signed-off-by: Flavio Leitner <redacted>
---
 drivers/net/bonding/bond_main.c |   61 +++++++++++++++++++++++++++++++++-----
 drivers/net/bonding/bonding.h   |    1 +
 2 files changed, 54 insertions(+), 8 deletions(-)

[...]

quoted

@@ -944,7 +979,9 @@ static void bond_mc_swap(struct bonding *bond, struct slave *new_active,
 
 		netdev_for_each_mc_addr(ha, bond->dev)
 			dev_mc_add(new_active->dev, ha->addr);
-		bond_resend_igmp_join_requests(bond);
+
+		/* rejoin multicast groups */
+		queue_delayed_work(bond->wq, &bond->mcast_work, 0);
 	}
 }
 

I was hoping that one patch would just make the changes so
retransmission was supported on VLANs and the second patch would queue
the work and add the tunable for multiple retransmissions, but I guess
it wasn't clear enough.

I felt like that would divide the patches up into the bug-fix (VLANs +
multicast not working) and the new feature (multiple retransmissions
from the workqueue).

I'm not seeing how to that because the first patch changes to send
the membership directly and not using timers anymore, so the call
trace usually is:

 write_lock_bh(&bond->curr_slave_lock); <-- hold lock
 bond_select_active_slave() 
  ->bond_change_active_slave()
     ->bond_mc_swap()
        ->tx membership reports
 

then trying to send the IGMP packet directly, it will end up at:
  bond_start_xmit()
   ->bond_xmit_activebackup() (mode=1, for example)
      ->read_lock(&bond->lock);
      ->read_lock(&bond->curr_slave_lock); <-- deadlock

I will test these out this morning and make sure things look good.

I have a better patch sequence which I'm planning post replying to
this thread as soon as I finish up testing them. It is still using
workqueue though.

--
Flavio