netdev - Re: [PATCH] net: Prevent multiple NAPI instances co-existing in the list

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CA+U0gVi1cVB4qbXAkPp1LMmNOaDOD2UaAL4riA6O_Q_SnvMQTA@mail.gmail.com>
Date:	Fri, 9 Jan 2015 10:26:48 +0800
From:	Dennis Chen <kernel.org.gnu@...il.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	netdev <netdev@...r.kernel.org>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Miller <davem@...emloft.net>
Subject: Re: [PATCH] net: Prevent multiple NAPI instances co-existing in the list

I am very curious about the reason that you're removing the atomic ops
in the stack, what's the benifit?

On Thu, Jan 8, 2015 at 10:51 PM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> On Thu, 2015-01-08 at 16:22 +0800, Dennis Chen wrote:
>> Some drivers may clear the NAPI_STATE_SCHED bit upon the state of the
>> NAPI instance after exhaust the budget in the poll function, which
>> will open a window for next device interrupt handler to insert a same
>> instance to the list after calling list_add_tail(&n->poll_list,
>> repoll) if we don't set this bit.
>>
>> Signed-off-by: Dennis Chen <kernel.org.gnu@...il.com>
>> ---
>
>
> Well no.
>
> I am removing some atomic ops in the stack, please do not add new ones,
> especially if no driver is that buggy.
>
> The unlikely() wont help the expensive stuff being done here.
>
>



-- 
Den
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html