Subject: Re: [PATCH 6/13] bridge: Add core IGMP snooping support

From: "Paul E. McKenney" <[email-masked]>
Date: Wed, 10 Mar 2010 08:26:58 -0800

On Wed, Mar 10, 2010 at 10:07:29PM +0800, Herbert Xu wrote:
> On Wed, Mar 10, 2010 at 05:13:18AM -0800, Paul E. McKenney wrote:
> >
> > If CONFIG_PROVE_RCU is set, rcu_dereference() checks for rcu_read_lock()
> > and rcu_dereference_bh() checks for either rcu_read_lock_bh() or BH
> > being disabled.  Yes, this is a bit restrictive, but there are a few too
> > many to check by hand these days.
> 
> Fair enough.  We should get those fixed then.  In fact I reckon
> most of them should be using the BH variant so we might be able
> to kill a few rcu_read_lock's which would be a real gain.

I have -tip commit a898def29e4119bc01ebe7ca97423181f4c0ea2d that
converts some of the rcu_dereference()s in net/core/filter.c,
net/core/dev.c, net/decnet/dn_route.c, net/packet/af_packet.c, and
net/ipv4/route.c to rcu_dereference_bh().

How should we coordinate the removal of the rcu_read_lock() calls?

							Thanx, Paul