From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Benjamin Poirier <bpoirier@suse.de>
Cc: netdev@vger.kernel.org, Patrick McHardy <kaber@trash.net>,
"David S. Miller" <davem@davemloft.net>,
Andrew Morton <akpm@linux-foundation.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
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 2/2] netfilter: conntrack: replace mutex with cmpxchg
Date: Wed, 2 May 2012 02:51:02 +0200 [thread overview]
Message-ID: <20120502005102.GB14999@1984> (raw)
In-Reply-To: <1335551333-6103-2-git-send-email-bpoirier@suse.de>
On Fri, Apr 27, 2012 at 02:28:53PM -0400, Benjamin Poirier wrote:
> This mutex protects a single pointer.
You seem to be using an old Linux kernel tree. This doesn't apply.
> ---
> net/netfilter/nf_conntrack_ecache.c | 38 +++++++++-------------------------
> 1 files changed, 10 insertions(+), 28 deletions(-)
>
> diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c
> index 0134009..603eb69 100644
> --- a/net/netfilter/nf_conntrack_ecache.c
> +++ b/net/netfilter/nf_conntrack_ecache.c
> @@ -25,8 +25,6 @@
> #include <net/netfilter/nf_conntrack_core.h>
> #include <net/netfilter/nf_conntrack_extend.h>
>
> -static DEFINE_MUTEX(nf_ct_ecache_mutex);
> -
> /* deliver cached events and clear cache entry - must be called with locally
> * disabled softirqs */
> void nf_ct_deliver_cached_events(struct nf_conn *ct)
> @@ -80,52 +78,36 @@ EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
> int nf_conntrack_register_notifier(struct net *net,
> struct nf_ct_event_notifier *new)
> {
> - int ret = 0;
> -
> - mutex_lock(&nf_ct_ecache_mutex);
> - if (net->ct.nf_conntrack_event_cb != NULL)
> - ret = -EBUSY;
> + if (cmpxchg(&net->ct.nf_conntrack_event_cb, NULL, new) != NULL)
> + return -EBUSY;
> else
> - net->ct.nf_conntrack_event_cb = new;
> - mutex_unlock(&nf_ct_ecache_mutex);
> -
> - return ret;
> + return 0;
> }
> EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
>
> void nf_conntrack_unregister_notifier(struct net *net,
> struct nf_ct_event_notifier *new)
> {
> - mutex_lock(&nf_ct_ecache_mutex);
> - BUG_ON(net->ct.nf_conntrack_event_cb != new);
> - net->ct.nf_conntrack_event_cb = NULL;
> - mutex_unlock(&nf_ct_ecache_mutex);
> + if (xchg(&net->ct.nf_conntrack_event_cb, NULL) != new)
> + BUG();
> }
> EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier);
>
> int nf_ct_expect_register_notifier(struct net *net,
> struct nf_exp_event_notifier *new)
> {
> - int ret = 0;
> -
> - mutex_lock(&nf_ct_ecache_mutex);
> - if (net->ct.nf_expect_event_cb != NULL)
> - ret = -EBUSY;
> + if (cmpxchg(&net->ct.nf_expect_event_cb, NULL, new) != NULL)
> + return -EBUSY;
> else
> - net->ct.nf_expect_event_cb = new;
> - mutex_unlock(&nf_ct_ecache_mutex);
> -
> - return ret;
> + return 0;
> }
> EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier);
>
> void nf_ct_expect_unregister_notifier(struct net *net,
> struct nf_exp_event_notifier *new)
> {
> - mutex_lock(&nf_ct_ecache_mutex);
> - BUG_ON(net->ct.nf_expect_event_cb != new);
> - net->ct.nf_expect_event_cb = NULL;
> - mutex_unlock(&nf_ct_ecache_mutex);
> + if (xchg(&net->ct.nf_expect_event_cb, NULL) != new)
> + BUG();
> }
> EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier);
>
> --
> 1.7.7
>
> --
> To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2012-05-02 0:51 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 [this message]
2012-04-27 18:58 ` [PATCH RFC 1/2] netfilter: conntrack: remove RCU usage in conntrack notifier Eric Dumazet
2012-04-27 20:14 ` Benjamin Poirier
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