netdev - Re: [PATCH net-next 2/2] sunvnet: vnet_start

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: <542C61DD.8010504@oracle.com>
Date:	Wed, 01 Oct 2014 16:19:41 -0400
From:	Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	davem@...emloft.net, raghuram.kothakota@...cle.com,
	netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/2] sunvnet: vnet_start_xmit() must hold a refcnt
 on port.

On 10/01/2014 04:15 PM, Eric Dumazet wrote:
> On Wed, 2014-10-01 at 15:44 -0400, Sowmini Varadhan wrote:
>> On (10/01/14 12:05), Eric Dumazet wrote:
>>>
>>> Hmpff... This calls for rcu protection here !
>>>
>>
>> I did consider that, but given that the lists containing the ports are
>> accessed in multiple contexts, some of which can sleep, and given that
>> the vnet port is similar in spirit to the net_device, I followed the
>> net_device model of dev_put etc.
>
> dev_put() uses per cpu variables, an order of magnitude faster than a
> atomic put/get :(

I could make this a per-cpu variable, it would not be too hard to change
vnet_put/hold etc. That's not a problem.

--Sowmini


--
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