netdev - Re: [Patch net-next] ipv4: get rid of ip_ra

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Message-ID: <CAM_iQpXexP9OzzqyPJ-yHmyq-ZF=cNboaG8566yaxZKbn0+TTg@mail.gmail.com>
Date:   Thu, 27 Apr 2017 16:46:25 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [Patch net-next] ipv4: get rid of ip_ra_lock

On Thu, Apr 27, 2017 at 5:46 AM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> On Wed, 2017-04-26 at 13:55 -0700, Cong Wang wrote:
>> After commit 1215e51edad1 ("ipv4: fix a deadlock in ip_ra_control")
>> we always take RTNL lock for ip_ra_control() which is the only place
>> we update the list ip_ra_chain, so the ip_ra_lock is no longer needed,
>> we just need to disable BH there.
>>
>> Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
>> ---
>
> Looks great, but reading again this code, I believe we do not need to
> disable BH at all ?
>

Hmm, if we don't disable BH here, a reader in BH could jump in and
break this critical section? Or that is fine for RCU?