Re: [PATCH tip/core/urgent 1/4] rcu: add rcu_access_pointer and rcu_dereference_protected

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Fri, Apr 09, 2010 at 11:24:18AM +0200, Eric Dumazet wrote:
> Le vendredi 09 avril 2010 à 10:10 +0100, David Howells a écrit :
> > Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> > 
> > > +#define rcu_access_pointer(p) ((void *)ACCESS_ONCE(p))
> > > ...
> > > +#define rcu_access_pointer(p)		((void *)ACCESS_ONCE(p))
> > 
> > There's no difference between your two versions of rcu_access_pointer(), so
> > you could move that whole construct outside of the #ifdef'ed section.
> > 
> > Other than that:
> > 
> > Acked-by: David Howells <dhowells@redhat.com>
> 
> I also prefer to keep type checking if possible
> 
> #define rcu_access_pointer(p)		(ACCESS_ONCE(p))

Yikes!  I was obsessing on preventing people from dereferencing the
pointer, but you are quite right, they might be comparing it to a
constant pointer to check for array bounds or for use of a statically
allocated emergency-pool item.

I will fix and resubmit.

> Other than that:
> 
> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>

							Thanx, Paul