From: Eric Dumazet <eric.dumazet@gmail.com>
To: Cong Wang <amwang@redhat.com>
Cc: netdev@vger.kernel.org,
Stephen Hemminger <stephen@networkplumber.org>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [Patch net-next v5 3/3] igmp: convert RTNL lock to a spinlock
Date: Sat, 15 Jun 2013 00:55:46 -0700 [thread overview]
Message-ID: <1371282946.3252.148.camel@edumazet-glaptop> (raw)
In-Reply-To: <1371282069-26893-3-git-send-email-amwang@redhat.com>
On Sat, 2013-06-15 at 15:41 +0800, Cong Wang wrote:
> From: Cong Wang <amwang@redhat.com>
>
> It is not necessary to hold RTNL lock to protect mc_list,
> at least IPv6 mcast is using a local spinlock, IPv4 can do
> this too. This patch converts RTNL lock+RCU to spinlock+RCU.
>
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Stephen Hemminger <stephen@networkplumber.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Signed-off-by: Cong Wang <amwang@redhat.com>
> ---
> v5: no change
> v4: rebased on the latest net-next.
> v3: remove useless synchronize_rcu().
Really I think this patch is not needed and way too risky.
I already said that you added bugs, and you keep posting same bugs ?
ip_mc_join_group() seems buggy after your v5 patch ?
Let me repeat : fast path already uses RCU.
The writer parts are slow path, using a mutex is much better than a
spinlock as a mutex allows the writer to use GFP_KERNEL allocations, and
eventually be preempted/scheduled.
Just leave this code as is, this is a waste of time.
next prev parent reply other threads:[~2013-06-15 7:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-15 7:41 [Patch net-next v5 1/3] igmp: make some functions void Cong Wang
2013-06-15 7:41 ` [Patch net-next v5 2/3] ipv6,mcast: " Cong Wang
2013-06-15 7:41 ` [Patch net-next v5 3/3] igmp: convert RTNL lock to a spinlock Cong Wang
2013-06-15 7:55 ` Eric Dumazet [this message]
2013-06-15 8:12 ` Cong Wang
2013-06-15 8:26 ` Eric Dumazet
2013-06-15 8:44 ` Cong Wang
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