Re: [PATCH v4 net-next 02/12] bonding: permit using arp_validate with non-ab modes

On Mon, Feb 17, 2014 at 04:22:21PM +0100, Nikolay Aleksandrov wrote:

On 02/17/2014 03:41 PM, Veaceslav Falico wrote:

quoted

Currently it's disabled because it's sometimes hard, in typical configs, to
make it work - because of the nature how the loadbalance modes work - as
it's hard to deliver valid arp replies to correct slaves by the switch.

However we still can use arp_validation in loadbalance with several other
configs, per example with arp_validate == 2 for backup with one broadcast
domain, without the switch(es) doing any balancing - this way we'd be (a
bit more) sure that the slave is up.

So, enable it to let users decide which one works/suits them best. Also
remove the mode limitation from BOND_OPT_ARP_VALIDATE.

CC: Jay Vosburgh <redacted>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <redacted>
---
 Documentation/networking/bonding.txt | 6 +++---
 drivers/net/bonding/bond_main.c      | 4 ----
 drivers/net/bonding/bond_options.c   | 1 -
 3 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 5cdb229..96b4ad8 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt

@@ -270,9 +270,9 @@ arp_ip_target
 arp_validate

 	Specifies whether or not ARP probes and replies should be
-	validated in the active-backup mode.  This causes the ARP
-	monitor to examine the incoming ARP requests and replies, and
-	only consider a slave to be up if it is receiving the
+	validated in any mode that supports arp monitoring.  This causes
+	the ARP monitor to examine the incoming ARP requests and replies,
+	and only consider a slave to be up if it is receiving the
 	appropriate ARP traffic.

 	Possible values are:

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 3c50bec..91c0248 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c

@@ -4183,10 +4183,6 @@ static int bond_check_params(struct bond_params *params)
 	}

 	if (arp_validate) {
-		if (bond_mode != BOND_MODE_ACTIVEBACKUP) {
-			pr_err("arp_validate only supported in active-backup mode\n");
-			return -EINVAL;
-		}
 		if (!arp_interval) {
 			pr_err("arp_validate requires arp_interval\n");
 			return -EINVAL;

diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index f3eb44d..d566cab 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c

@@ -151,7 +151,6 @@ static struct bond_option bond_opts[] = {
 		.id = BOND_OPT_ARP_VALIDATE,
 		.name = "arp_validate",
 		.desc = "validate src/dst of ARP probes",
-		.unsuppmodes = BOND_MODE_ALL_EX(BIT(BOND_MODE_ACTIVEBACKUP)),
 		.values = bond_arp_validate_tbl,
 		.set = bond_option_arp_validate_set
 	},

Sorry for not noticing before, but I just remembered the reason why all the
checks are there when changing the recv_probe, especially from the options.
The problem was that lacp mode also uses the recv_probe, so after this patch we
can overwrite the recv_probe while it's running in lacp mode, because
bond_option_arp_validate_set changes the recv_probe. We can actually only set it
to NULL because arp_interval can't be set in those modes, but still we can break
the mode and there'll be need for at least down/up cycle to fix it.
I think rlb also uses the recv_probe so this applies to it as well.

Yep, missed that too, thanks a lot Nik. It should just be the same as for
BOND_OPT_ARP_INTERVAL:

  177                 .unsuppmodes = BIT(BOND_MODE_8023AD) | BIT(BOND_MODE_TLB) |
  178                                BIT(BOND_MODE_ALB),

which makes sense - as in those modes it's indeed more than useless.

I'll change it and send v5.

Nik