netdev - Re: [PATCH v4 net-next 6/7] net: ethtool: add a mutex protecting RSS contexts

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: <70e5af64-b696-dec1-1afd-730559b96bfd@gmail.com>
Date: Thu, 5 Oct 2023 21:56:47 +0100
From: Edward Cree <ecree.xilinx@...il.com>
To: Jakub Kicinski <kuba@...nel.org>, edward.cree@....com
Cc: linux-net-drivers@....com, davem@...emloft.net, edumazet@...gle.com,
 pabeni@...hat.com, netdev@...r.kernel.org, habetsm.xilinx@...il.com,
 sudheer.mogilappagari@...el.com, jdamato@...tly.com, andrew@...n.ch,
 mw@...ihalf.com, linux@...linux.org.uk, sgoutham@...vell.com,
 gakula@...vell.com, sbhatta@...vell.com, hkelam@...vell.com,
 saeedm@...dia.com, leon@...nel.org
Subject: Re: [PATCH v4 net-next 6/7] net: ethtool: add a mutex protecting RSS
 contexts

On 05/10/2023 00:16, Jakub Kicinski wrote:
> On Wed, 27 Sep 2023 19:13:37 +0100 edward.cree@....com wrote:
>> While this is not needed to serialise the ethtool entry points (which
>>  are all under RTNL), drivers may have cause to asynchronously access
>>  dev->ethtool->rss_ctx; taking dev->ethtool->rss_lock allows them to
>>  do this safely without needing to take the RTNL.
> 
> Can we use a replay mechanism, like we do in TC offloads and VxLAN/UDP
> ports? The driver which lost config can ask for the rss contexts to be
> "replayed" and the core will issue a series of ->create calls for all
> existing entries?

I like that idea, yes.  Will try to implement it for v5.
There is a question as to how the core should react if the ->create call
 then fails; see my reply to Martin on #7.

> Regarding the lock itself - can we hide it under ethtool_rss_lock(dev)
> / ethtool_rss_unlock(dev) helpers?

Sure.  If I can't get replay to work then I'll do that.

-ed