Re: [Xen-devel] [PATCH v2 06/32] s390: reuse asm-generic/barrier.h

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

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:
> > 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@xxxxxxxxxx>
> > Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
> > ---
> >  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

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