netdev - Re: [RFC v3 3/6] can: make struct proto const

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: <4D7FD9ED.1080004@hartkopp.net>
Date:	Tue, 15 Mar 2011 22:28:13 +0100
From:	Oliver Hartkopp <socketcan@...tkopp.net>
To:	Kurt Van Dijck <kurt.van.dijck@....be>,
	Eric Dumazet <eric.dumazet@...il.com>
CC:	socketcan-core@...ts.berlios.de, netdev@...r.kernel.org
Subject: Re: [RFC v3 3/6] can: make struct proto const

On 14.03.2011 18:17, Kurt Van Dijck wrote:
> On Mon, Mar 14, 2011 at 05:42:23PM +0100, Eric Dumazet wrote:
>> Le lundi 14 mars 2011 à 16:02 +0100, Kurt Van Dijck a écrit :
>>
>>> I see your point.
>>> The reason I modified this was, as described, checkpatch.pl was complaining.
>>> Anyway, this sequence was protected by a spinlock 'proto_tab_lock'.
>>> I don't think it was a race.
>>>
>>> Did I miss something?
>>
>> As soon as proto_tab[proto] = cp; is done, another thread on another cpu
>> can read the pointer and follow it.
>>
>> Hmm, I missed can_create() also uses the spinlock protection, so you're
>> probably right.
>>
>> It seems a bit overkill :(
>> phonet uses RCU for example.

Hello Eric,

the RCU code in phonet is worth to consider. But loading and removing of
protocols is far away from being a hot path ... what would be the advantages
to move to RCU here?

> I'll keep that in mind.
> Switching CAN protos to RCU is far beyond to goal of this patch :-)

Anyway making the struct proto a const (and set the default defines in the CAN
protocols) is a nice cleanup. Let's wait for the feedback about the RCU from
Eric ... then this patch could be put into mainline independently from the
j1939 protocol.

Thanks,
Oliver
--
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