From: Nikolay Aleksandrov <nikolay@redhat.com>
To: Veaceslav Falico <vfalico@redhat.com>
Cc: dingtianhong <dingtianhong@huawei.com>,
Jay Vosburgh <fubar@us.ibm.com>,
Andy Gospodarek <andy@greyhouse.net>,
"David S. Miller" <davem@davemloft.net>,
Netdev <netdev@vger.kernel.org>
Subject: Re: [3/4] bonding: the calling of bond->slave_cnt need protection
Date: Sat, 20 Jul 2013 14:42:37 +0200 [thread overview]
Message-ID: <51EA85BD.2080409@redhat.com> (raw)
In-Reply-To: <20130720104746.GC9149@redhat.com>
On 07/20/2013 12:47 PM, Veaceslav Falico wrote:
> On Sat, Jul 20, 2013 at 03:23:57PM +0800, dingtianhong wrote:
>> The bonding_store_mode has rtnl protection, so no need to get read lock
>> for bond->slave_cnt, but the bonding_store_fail_over_mac need to protect
>> the bond->slave_cnt, so add read_lock().
>>
>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
>>
<snip>
>
> Maybe it's Saturday, but I really don't see *any* point in this locking.
>
> I think you've meant that we need the rtnl protection while reading
> slave_cnt AND updating the .fail_over_mac, so that in between we won't add
> new slaves with outdated params.
>
> Something like this (untested):
>
Indeed, Veaceslav's way is the correct one (I've looked at this race
before), but IMO it's not worth it to protect fail_over_mac as the worst
that could happen is inconsistency with the MAC addresses which isn't
fatal. Anyway, I still haven't had my coffee and might be missing something :-)
Cheers,
Nik
next prev parent reply other threads:[~2013-07-20 12:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-20 7:23 [PATCH 3/4] bonding: the calling of bond->slave_cnt need protection Ding Tianhong
2013-07-20 10:47 ` [3/4] " Veaceslav Falico
2013-07-20 12:42 ` Nikolay Aleksandrov [this message]
2013-07-20 15:00 ` Veaceslav Falico
2013-07-22 0:47 ` Ding Tianhong
2013-07-22 0:42 ` Ding Tianhong
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