netdev - Re: [PATCH net-next 1/3] bonding: Set the correct value to fail_over

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Date:	Wed, 22 Jan 2014 12:51:27 -0800
From:	Jay Vosburgh <fubar@...ibm.com>
To:	Ding Tianhong <dingtianhong@...wei.com>
cc:	Veaceslav Falico <vfalico@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Netdev <netdev@...r.kernel.org>,
	Andy Gospodarek <andy@...yhouse.net>
Subject: Re: [PATCH net-next 1/3] bonding: Set the correct value to fail_over_mac at enslavement

Ding Tianhong <dingtianhong@...wei.com> wrote:

>If the new slave don't support setting the MAC address, there are
>two ways to handle this situation:
>
>1). If the new slave is the first slave, set bond to the new slave's
>    MAC address, if the mode is active-backup, set fail_over_mac to
>    active, otherwise set fail_over_mac to none.

	This should be "if the mode is active-backup, set fail_over_mac
to active, otherwise do not change fail_over_mac."  Setting to none here
would undo any setting of fail_over_mac that the user had set prior to
adding the first slave.

>2). If the new slave is not the first slave and the fail_over_mac is
>    active, it means that the slave could work normally in active-backup
>    mode, otherwise if the fail_over_mac is none, the slave could not
>    work normally for no active-backup mode, so bond could not ensalve
>    the new dev.

	This (#2) is not a code change, correct?  You're just restating
the existing behavior of the code, right?

	Also, I don't see where this patch set updates the slave removal
processing where the slave's original MAC is restored.  At present, this
is done by a test against fail_over_mac, but should be tested against
the mode and fail_over_mac.

	My comment to the prior version of this patchset, again:

	The correct way to fix this in general is to permit setting an
option at any time, but only have it take effect in active-backup mode.
This minimizes ordering requirements when setting options.

	I would instead modify the bond enslave and removal processing
to check the mode in addition to fail_over_mac when setting a slave's
MAC during enslavement.  The change active slave processing already only
calls the fail_over_mac function when in active-backup mode.  This
should also be a simpler change set.

	These comments still apply to this version of the patchset.

	-J

>Cc: Jay Vosburgh <fubar@...ibm.com>
>Cc: Veaceslav Falico <vfalico@...hat.com>
>Cc: Andy Gospodarek <andy@...yhouse.net>
>Signed-off-by: Ding Tianhong <dingtianhong@...wei.com>
>---
> drivers/net/bonding/bond_main.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 3220b48..598f100 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -1334,9 +1334,17 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>
> 	if (slave_ops->ndo_set_mac_address == NULL) {
> 		if (!bond_has_slaves(bond)) {
>-			pr_warning("%s: Warning: The first slave device specified does not support setting the MAC address. Setting fail_over_mac to active.",
>+			pr_warning("%s: Warning: The first slave device specified does not support setting the MAC address.\n",
> 				   bond_dev->name);
>-			bond->params.fail_over_mac = BOND_FOM_ACTIVE;
>+			if (bond->params.mode == BOND_MODE_ACTIVEBACKUP) {
>+				bond->params.fail_over_mac = BOND_FOM_ACTIVE;
>+				pr_warning("%s: Setting fail_over_mac to active for active-backup mode.\n",
>+					   bond_dev->name);
>+			} else {
>+				bond->params.fail_over_mac = BOND_FOM_NONE;
>+				pr_warning("%s: Setting fail_over_mac to none for no active-backup modes",
>+					   bond_dev->name);
>+			}
> 		} else if (bond->params.fail_over_mac != BOND_FOM_ACTIVE) {
> 			pr_err("%s: Error: The slave device specified does not support setting the MAC address, but fail_over_mac is not set to active.\n",
> 			       bond_dev->name);
>-- 
>1.8.0

---
	-Jay Vosburgh, IBM Linux Technology Center, fubar@...ibm.com

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