Re: [Open-FCoE] [PATCH] fcoe: correct checking for bonding

[Jiri Pirko <jpirko@redhat.com>]

Mon, Feb 28, 2011 at 06:54:29PM CET, joe.eykholt@gmail.com wrote:
>On 2/28/11 9:15 AM, Jay Vosburgh wrote:
>>Jiri Pirko<jpirko@redhat.com>  wrote:
>>
>>>Check for IFF_BONDING as this flag is set-up for all bonding devices.
>>>
>>>Signed-off-by: Jiri Pirko<jpirko@redhat.com>
>>>---
>>>drivers/scsi/fcoe/fcoe.c |    4 +---
>>>1 files changed, 1 insertions(+), 3 deletions(-)
>>>
>>>diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
>>>index 9f9600b..67714a4 100644
>>>--- a/drivers/scsi/fcoe/fcoe.c
>>>+++ b/drivers/scsi/fcoe/fcoe.c
>>>@@ -285,9 +285,7 @@ static int fcoe_interface_setup(struct fcoe_interface *fcoe,
>>>	}
>>>
>>>	/* Do not support for bonding device */
>>>-	if ((netdev->priv_flags&  IFF_MASTER_ALB) ||
>>>-	    (netdev->priv_flags&  IFF_SLAVE_INACTIVE) ||
>>>-	    (netdev->priv_flags&  IFF_MASTER_8023AD)) {
>>>+	if (netdev->priv_flags&  IFF_BONDING) {
>>>		FCOE_NETDEV_DBG(netdev, "Bonded interfaces not supported\n");
>>>		return -EOPNOTSUPP;
>>>	}
>>
>>	Based on past discussions, I believe the intent of the code is
>>to permit FCOE over bonding only for active-backup mode, and possibly
>>for -xor/-rr as well.
>>
>>	I'm not sure if the slave or the master is what's being tested
>>here, so I'm not sure what the right thing to do is.  I suspect it's the
>>master, as I recall discussion of one configuration involving
>>active-backup mode balancing FCOE traffic over both the active and
>>inactive slaves.  FCOE uses the "orig_dev" logic in __netif_receive_skb
>>to have the packets delivered even on the nominally inactive slave.
>>
>>	-J
>>
>>---
>>	-Jay Vosburgh, IBM Linux Technology Center, fubar@us.ibm.com
>
>Right.  That was the intent.  It should work on the physical dev, but probably
>not on the master of the bond.
>
>If you have a master/slave bond for IPv4 between eth1 and eth2, say,
>and they are going to two different DCE (FCoE) switches, presumably on
>different VSANs but with ultimate access to the same disks,
>then you want to split the FCoE traffic in active/active
>mode using separate FCoE instances on eth1 and eth2 even though IP
>is using active/standby on bond0.  This should work.  But, putting fcoe
>on bond0 isn't going to do what you want.
>
>However, it seems like the check above shouldn't be checking
>IFF_SLAVE_INACTIVE.   I can't test this.

OK. So I guess the right check should be for:
(netdev->priv_flags & IFF_BONDING && netdev->flags & IFF_MASTER)

This would disable adding all bond devices (like bond0 etc) and allows
to use enslaved physdevs.

Note that checking for mode is irrelevant here. Mode could be easily
changed later without fcoe knowing that.

Jirka
>
>	Joe
>