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SubjectRe: [PATCH v2 20/32] metag: define __smp_xxx
On Tue, Jan 05, 2016 at 12:09:30AM +0000, James Hogan wrote:
> Hi Michael,
>
> On Thu, Dec 31, 2015 at 09:08:22PM +0200, Michael S. Tsirkin wrote:
> > This defines __smp_xxx barriers for metag,
> > for use by virtualization.
> >
> > smp_xxx barriers are removed as they are
> > defined correctly by asm-generic/barriers.h
> >
> > Note: as __smp_XX macros should not depend on CONFIG_SMP, they can not
> > use the existing fence() macro since that is defined differently between
> > SMP and !SMP. For this reason, this patch introduces a wrapper
> > metag_fence() that doesn't depend on CONFIG_SMP.
> > fence() is then defined using that, depending on CONFIG_SMP.
>
> I'm not a fan of the inconsistent commit message wrapping. I wrap to 72
> columns (although I now notice SubmittingPatches says to use 75...).
>
> >
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > arch/metag/include/asm/barrier.h | 32 +++++++++++++++-----------------
> > 1 file changed, 15 insertions(+), 17 deletions(-)
> >
> > diff --git a/arch/metag/include/asm/barrier.h b/arch/metag/include/asm/barrier.h
> > index b5b778b..84880c9 100644
> > --- a/arch/metag/include/asm/barrier.h
> > +++ b/arch/metag/include/asm/barrier.h
> > @@ -44,13 +44,6 @@ static inline void wr_fence(void)
> > #define rmb() barrier()
> > #define wmb() mb()
> >
> > -#ifndef CONFIG_SMP
> > -#define fence() do { } while (0)
> > -#define smp_mb() barrier()
> > -#define smp_rmb() barrier()
> > -#define smp_wmb() barrier()
> > -#else
>
> !SMP kernel text differs, but only because of new presence of unused
> metag_fence() inline function. If I #if 0 that out, then it matches, so
> thats fine.
>
> > -
> > #ifdef CONFIG_METAG_SMP_WRITE_REORDERING
> > /*
> > * Write to the atomic memory unlock system event register (command 0). This is
> > @@ -60,26 +53,31 @@ static inline void wr_fence(void)
> > * incoherence). It is therefore ineffective if used after and on the same
> > * thread as a write.
> > */
> > -static inline void fence(void)
> > +static inline void metag_fence(void)
> > {
> > volatile int *flushptr = (volatile int *) LINSYSEVENT_WR_ATOMIC_UNLOCK;
> > barrier();
> > *flushptr = 0;
> > barrier();
> > }
> > -#define smp_mb() fence()
> > -#define smp_rmb() fence()
> > -#define smp_wmb() barrier()
> > +#define __smp_mb() metag_fence()
> > +#define __smp_rmb() metag_fence()
> > +#define __smp_wmb() barrier()
> > #else
> > -#define fence() do { } while (0)
> > -#define smp_mb() barrier()
> > -#define smp_rmb() barrier()
> > -#define smp_wmb() barrier()
> > +#define metag_fence() do { } while (0)
> > +#define __smp_mb() barrier()
> > +#define __smp_rmb() barrier()
> > +#define __smp_wmb() barrier()
>
> Whitespace is now messed up. Admitedly its already inconsistent
> tabs/spaces, but it'd be nice if the definitions at least still all
> lined up. You're touching all the definitions which use spaces anyway,
> so feel free to convert them to tabs while you're at it.
>
> Other than those niggles, it looks sensible to me:
> Acked-by: James Hogan <james.hogan@imgtec.com>
>
> Cheers
> James

Thanks!

I did this in my tree (replaced spaces with tabs in the new
definitions); not reposting just because of this change.

> > #endif
> > +
> > +#ifdef CONFIG_SMP
> > +#define fence() metag_fence()
> > +#else
> > +#define fence() do { } while (0)
> > #endif
> >
> > -#define smp_mb__before_atomic() barrier()
> > -#define smp_mb__after_atomic() barrier()
> > +#define __smp_mb__before_atomic() barrier()
> > +#define __smp_mb__after_atomic() barrier()
> >
> > #include <asm-generic/barrier.h>
> >
> > --
> > MST
> >


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