Messages in this thread | | | Date | Tue, 10 Oct 2017 13:50:39 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH 13/13] rcutorture: formal: prepare for ACCESS_ONCE() removal |
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On Tue, Oct 10, 2017 at 05:47:12AM -0700, Paul E. McKenney wrote: > On Tue, Oct 10, 2017 at 10:54:14AM +0100, Mark Rutland wrote: > > On Mon, Oct 09, 2017 at 12:51:12PM -0700, Paul E. McKenney wrote: > > > On Mon, Oct 09, 2017 at 07:28:50PM +0100, Mark Rutland wrote: > > > > diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h > > > > index 6687acc..ee4e4f8 100644 > > > > --- a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h > > > > +++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h > > > > @@ -34,8 +34,9 @@ > > > > #define rs_smp_mb() do {} while (0) > > > > #endif > > > > > > > > -#define ACCESS_ONCE(x) (*(volatile typeof(x) *) &(x)) > > > > -#define READ_ONCE(x) ACCESS_ONCE(x) > > > > -#define WRITE_ONCE(x, val) (ACCESS_ONCE(x) = (val)) > > > > +#define __ACCESS_ONCE(x) (*(volatile typeof(x) *) &(x)) > > > > +#define ACCESS_ONCE(x) __ACCESS_ONCE(x) > > > > +#define READ_ONCE(x) __ACCESS_ONCE(x) > > > > +#define WRITE_ONCE(x, val) (__ACCESS_ONCE(x) = (val)) > > > > > > How about something like the following? > > > > > > #define READ_ONCE(x) (*(volatile typeof(x) *) &(x)) > > > #define WRITE_ONCE(x) ((*(volatile typeof(x) *) &(x)) = (val)) > > > > Sure; folded in and pushed out. :) > > Thank you! > > > I've assumed that the ACCESS_ONCE() definition needs to be kept until > > that's ripped out treewide. Please shout if that's not the case! > > You have it right. This case is an exception because this code is > used only by RCU, which has long since had ACCESS_ONCE() ripped out.
Sorry; I meant that in this case, I leave this code as:
#define ACCESS_ONCE(x) (*(volatile typeof(x) *) &(x)) #define READ_ONCE(x) (*(volatile typeof(x) *) &(x)) #define WRITE_ONCE(x) ((*(volatile typeof(x) *) &(x)) = (val))
... if you mean that we can drop ACCESS_ONCE() in this case, then I can rip that out.
Thanks, Mark.
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