Re: [RFC net-next] bonding: Retry updating slave MAC after a failure

[Jay Vosburgh <jv@jvosburgh.net>]

Paritosh Potukuchi <paritoshpotukuchi@gmail.com> wrote:

>I came across this TODO in bond_set_mac_address() :
>
>        /* TODO: consider downing the slave
>         * and retry ?
>         * User should expect communications
>         * breakage anyway until ARP finish
>         * updating, so...
>         */
>
>Currently, if the dev_set_mac_address() fails on a slave, we go
>ahead and unwind the bond and its slaves.
>
>As the TODO suggests, one possible solution is to try setting
>the MAC again, after putting down the interface. This is because some 
>drivers may reject changing the MAC when the device is UP.
>
>The solution I am proposing is as follows:
>
>dev_set_mac_address on the slave
>        - If this fails, temporarily stop the slave - ndo_stop
>                - If stop fails, unwind
>        - call dev_set_mac_address() on the slave
>                - If this fails, unwind
>        - Bring up the slave by calling ndo_open
>                - If this fails, unwind
>If dev_set_mac_address on slave passes, we go to the next slave
>
>
>Before working on a patch, I wanted to get feedback on whether
>this interpretation of the TODO makes sense and whether there
>are concerns with temporarily stopping and restarting a slave
>during bond_set_mac_address().

	I think the proper thing to do is remove this comment block and
make no other changes.

	This comment dates to sometime before git, when it was common
for network device drivers to lack the ability to change the MAC while
the interface is up.  To the best of my knowledge, that isn't a issue
today.

	-J

---
	-Jay Vosburgh, jv@jvosburgh.net