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SubjectRe: [PATCH RFC 21/26] powerpc: Remove spin_unlock_wait() arch-specific definitions
On Sun, Jul 02, 2017 at 11:58:07AM +0800, Boqun Feng wrote:
> On Thu, Jun 29, 2017 at 05:01:29PM -0700, Paul E. McKenney wrote:
> > There is no agreed-upon definition of spin_unlock_wait()'s semantics,
> > and it appears that all callers could do just as well with a lock/unlock
> > pair. This commit therefore removes the underlying arch-specific
> > arch_spin_unlock_wait().
> >
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Cc: Paul Mackerras <paulus@samba.org>
> > Cc: Michael Ellerman <mpe@ellerman.id.au>
> > Cc: <linuxppc-dev@lists.ozlabs.org>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Alan Stern <stern@rowland.harvard.edu>
> > Cc: Andrea Parri <parri.andrea@gmail.com>
> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
>
> Acked-by: Boqun Feng <boqun.feng@gmail.com>

And finally applied in preparation for v2 of the patch series.

Thank you!!!

Thanx, Paul

> Regards,
> Boqun
>
> > ---
> > arch/powerpc/include/asm/spinlock.h | 33 ---------------------------------
> > 1 file changed, 33 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
> > index 8c1b913de6d7..d256e448ea49 100644
> > --- a/arch/powerpc/include/asm/spinlock.h
> > +++ b/arch/powerpc/include/asm/spinlock.h
> > @@ -170,39 +170,6 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
> > lock->slock = 0;
> > }
> >
> > -static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
> > -{
> > - arch_spinlock_t lock_val;
> > -
> > - smp_mb();
> > -
> > - /*
> > - * Atomically load and store back the lock value (unchanged). This
> > - * ensures that our observation of the lock value is ordered with
> > - * respect to other lock operations.
> > - */
> > - __asm__ __volatile__(
> > -"1: " PPC_LWARX(%0, 0, %2, 0) "\n"
> > -" stwcx. %0, 0, %2\n"
> > -" bne- 1b\n"
> > - : "=&r" (lock_val), "+m" (*lock)
> > - : "r" (lock)
> > - : "cr0", "xer");
> > -
> > - if (arch_spin_value_unlocked(lock_val))
> > - goto out;
> > -
> > - while (lock->slock) {
> > - HMT_low();
> > - if (SHARED_PROCESSOR)
> > - __spin_yield(lock);
> > - }
> > - HMT_medium();
> > -
> > -out:
> > - smp_mb();
> > -}
> > -
> > /*
> > * Read-write spinlocks, allowing multiple readers
> > * but only one writer.
> > --
> > 2.5.2
> >


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