On 10/29, Paul E. McKenney wrote: > > On Wed, Oct 29, 2014 at 11:57:04AM +0100, Peter Zijlstra wrote: > > On Tue, Oct 28, 2014 at 03:10:02PM -0700, Paul E. McKenney wrote: > > > From: "Paul E. McKenney" <[email protected]> > > > > > > Although rcu_dereference() and friends can be used in situations where > > > object lifetimes are being managed by something other than RCU, the > > > resulting sparse and lockdep-RCU noise can be annoying. This commit > > > therefore supplies a lockless_dereference(), which provides the > > > protection for dereferences without the RCU-related debugging noise. > > > > > > Reported-by: Al Viro <[email protected]> > > > Signed-off-by: Paul E. McKenney <[email protected]> > > > --- > > > > > +#define lockless_dereference(p) \ > > > +({ \ > > > + typeof(p) _________p1 = ACCESS_ONCE(p); \ > > > + smp_read_barrier_depends(); /* Dependency order vs. p above. */ \ > > > + (_________p1); \ > > > +}) > > > > Should we not have at least a single user along with this? > > And we do. In fact, Al Viro has pulled this into his vfs.git tree and > so I will be dropping this patch in favor of his.
And it seems that most of smp_read_barrier_depends() users can be changed to use this helper. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
