From: Eric Dumazet <eric.dumazet@gmail.com>
To: Benjamin Poirier <bpoirier@suse.de>
Cc: netdev@vger.kernel.org, Pablo Neira Ayuso <pablo@netfilter.org>,
Patrick McHardy <kaber@trash.net>,
"David S. Miller" <davem@davemloft.net>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Frysinger <vapier@gentoo.org>, Arun Sharma <asharma@fb.com>,
netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org,
coreteam@netfilter.org, linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH RFC 1/2] netfilter: conntrack: remove RCU usage in conntrack notifier
Date: Fri, 27 Apr 2012 20:58:51 +0200 [thread overview]
Message-ID: <1335553131.2775.252.camel@edumazet-glaptop> (raw)
In-Reply-To: <1335551333-6103-1-git-send-email-bpoirier@suse.de>
On Fri, 2012-04-27 at 14:28 -0400, Benjamin Poirier wrote:
> I think that the rcu usage in this code is pointless. It should either be
> removed or, if it was intended to protect against something, it ought to make
> that clear.
>
> 1) The code does not make use of the deferred deletion/wait for completion rcu
> api (ie. synchronize_rcu(), call_rcu()).
> 2) It does not benefit from the barriers implied by the rcu primitives used.
> The code deals with callback pointers. There's no need to order writes to the
> function code (!) before writes to the function pointers here.
> ---
At a first glance, this seems pretty wrong.
code can disappear under you, thats for sure.
CONFIG_NF_CT_NETLINK=m
hint : module unload contains an rcu barrier.
next prev parent reply other threads:[~2012-04-27 18:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-27 18:28 [PATCH RFC 1/2] netfilter: conntrack: remove RCU usage in conntrack notifier Benjamin Poirier
2012-04-27 18:28 ` [PATCH RFC 2/2] netfilter: conntrack: replace mutex with cmpxchg Benjamin Poirier
2012-05-02 0:51 ` Pablo Neira Ayuso
2012-04-27 18:58 ` Eric Dumazet [this message]
2012-04-27 20:14 ` [PATCH RFC 1/2] netfilter: conntrack: remove RCU usage in conntrack notifier Benjamin Poirier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1335553131.2775.252.camel@edumazet-glaptop \
--to=eric.dumazet@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=asharma@fb.com \
--cc=bpoirier@suse.de \
--cc=coreteam@netfilter.org \
--cc=davem@davemloft.net \
--cc=kaber@trash.net \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=netfilter@vger.kernel.org \
--cc=pablo@netfilter.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=vapier@gentoo.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox