Subject: Re: [PATCH net] macvlan: don't touch promisc without passthrough

From: John Fastabend <[email-masked]>
Date: Wed, 12 Jun 2013 23:02:01 -0700

On 06/12/2013 06:56 AM, Sergei Shtylyov wrote:
> Hello.
>
> On 12-06-2013 15:34, Michael S. Tsirkin wrote:
>
>> commit df8ef8f3aaa6692970a436204c4429210addb23a in linux 3.5 added a way
>
>     Please also specify that commit's summary line in parens.
>
>> to control NOPROMISC macvlan flag through netlink.
>
>> However, with a non passthrough device we don't set promisc on open or
>> clear it on stop, even if NOPROMISC is off.  As a result:
>
>> If userspace clears NOPROMISC on open, then does not clear it on a
>> netlink command, promisc counter is not decremented on stop and there
>> will be no way to clear it once macvlan is detached.
>
>> If userspace does not clear NOPROMISC on open, then sets NOPROMISC on a
>> netlink command, promisc counter will be decremented from 0 and overflow
>> to fffffffff with no way to clear promisc afterwards.
>
>> To fix, simply ignore NOPROMISC flag in a netlink command for
>> non-passthrough devices, same as we do at open/stop.
>
>> While at it - since we touch this code anyway - check
>> dev_set_promiscuity return code and pass it to users (though an error
>> here is unlikely).
>
>> Cc: "David S. Miller" <[email-masked]>
>> CC: Roopa Prabhu <[email-masked]>
>> Cc: John Fastabend <[email-masked]>
>> Signed-off-by: Michael S. Tsirkin <[email-masked]>
>> ---
>
>> Please review, and consider for 3.10 and -stable.
>

Other than those few nits looks good to me thanks!

Reviewed-by: John Fastabend <[email-masked]>

-- 
John Fastabend         Intel Corporation