Messages in this thread | | | Date | Wed, 29 Oct 2014 05:42:03 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH tip/core/rcu 9/9] rcu: Provide counterpart to rcu_dereference() for non-RCU situations |
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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" <paulmck@linux.vnet.ibm.com> > > > > 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 <viro@ZenIV.linux.org.uk> > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > --- > > > +#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.
Thanx, Paul
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