On Mon, Jan 04, 2016 at 02:20:42PM +0100, Peter Zijlstra wrote:

On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote:

quoted

On s390 read_barrier_depends, smp_read_barrier_depends
smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the
asm-generic variants exactly. Drop the local definitions and pull in
asm-generic/barrier.h instead.

This is in preparation to refactoring this code area.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/s390/include/asm/barrier.h | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h
index 7ffd0b1..c358c31 100644
--- a/arch/s390/include/asm/barrier.h
+++ b/arch/s390/include/asm/barrier.h

@@ -30,14 +30,6 @@
 #define smp_rmb()			rmb()
 #define smp_wmb()			wmb()
 
-#define read_barrier_depends()		do { } while (0)
-#define smp_read_barrier_depends()	do { } while (0)
-
-#define smp_mb__before_atomic()		smp_mb()
-#define smp_mb__after_atomic()		smp_mb()

As per:

  lkml.kernel.org/r/20150921112252.3c2937e1@mschwide

s390 should change this to barrier() instead of smp_mb() and hence
should not use the generic versions.

Thanks Peter!

OK so I will just rename this to __smp_mb__before_atomic and
__smp_mb__after_atomic but keep them around.

I'm not changing these - that's best left to s390 maintainers.

Should I add a TODO comment to change them to barrier so
we don't forget?

-- 
MST