From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 13/13] rcutorture: formal: prepare for ACCESS_ONCE() removal
Date: Tue, 10 Oct 2017 07:52:52 -0700 [thread overview]
Message-ID: <20171010145252.GX3521@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171010125039.GI27659@leverpostej>
On Tue, Oct 10, 2017 at 01:50:39PM +0100, Mark Rutland wrote:
> 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.
We can drop ACCESS_ONCE() in this case.
Thanx, Paul
next prev parent reply other threads:[~2017-10-10 14:52 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-09 18:28 [PATCH 00/13] Preparatory work to kill off ACCESS_ONCE() Mark Rutland
2017-10-09 18:28 ` [PATCH 01/13] dm integrity: " Mark Rutland
2017-10-09 18:28 ` [PATCH 02/13] EDAC, altera: " Mark Rutland
2017-10-09 23:12 ` Thor Thayer
2017-10-10 9:30 ` Mark Rutland
2017-10-09 18:28 ` [PATCH 03/13] firmware/ivc: " Mark Rutland
2017-10-09 18:28 ` [PATCH 04/13] fs: dcache: " Mark Rutland
2017-10-09 18:28 ` [PATCH 05/13] fs: ncpfs: " Mark Rutland
2017-10-09 18:28 ` [PATCH 06/13] media: dvb_ringbuffer: " Mark Rutland
2017-10-09 18:28 ` [PATCH 07/13] net: netlink/netfilter: " Mark Rutland
2017-10-09 18:28 ` [PATCH 08/13] net/ipv4/tcp_input.c: " Mark Rutland
2017-10-09 19:03 ` Mark Rutland
2017-10-09 18:28 ` [PATCH 09/13] net: average: " Mark Rutland
2017-10-10 9:28 ` Mark Rutland
2017-10-09 18:28 ` [PATCH 10/13] samples: mic/mpssd/mpssd.c: " Mark Rutland
2017-10-09 18:28 ` [PATCH 11/13] selftests/powerpc: " Mark Rutland
2017-10-10 0:45 ` Michael Ellerman
2017-10-10 9:32 ` Mark Rutland
2017-10-09 18:28 ` [PATCH 12/13] workqueue: " Mark Rutland
2017-10-10 14:06 ` Tejun Heo
2017-10-10 16:21 ` Mark Rutland
2017-10-09 18:28 ` [PATCH 13/13] rcutorture: formal: prepare for ACCESS_ONCE() removal Mark Rutland
2017-10-09 19:51 ` Paul E. McKenney
2017-10-10 9:54 ` Mark Rutland
2017-10-10 12:47 ` Paul E. McKenney
2017-10-10 12:50 ` Mark Rutland
2017-10-10 14:52 ` Paul E. McKenney [this message]
2017-10-10 16:24 ` Mark Rutland
2017-10-10 16:35 ` Paul E. McKenney
2017-10-10 16:27 ` Joe Perches
2017-10-10 16:35 ` Paul E. McKenney
2017-10-10 16:41 ` Mark Rutland
2017-10-10 16:57 ` Joe Perches
2017-10-10 17:06 ` Mark Rutland
2017-10-09 20:02 ` [PATCH 00/13] Preparatory work to kill off ACCESS_ONCE() Paul E. McKenney
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