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Commit 193d2aad authored by David S. Miller's avatar David S. Miller
Browse files

sparc: Support atomic64_dec_if_positive properly. 



Sparc32 already supported it, as a consequence of using the
generic atomic64 implementation.  And the sparc64 implementation
is rather trivial.

This allows us to set ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE for all
of sparc, and avoid the annoying warning from lib/atomic64_test.c

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0bce04be

arch/sparc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ config SPARC 
	select HAVE_ARCH_TRACEHOOK

	select SYSCTL_EXCEPTION_TRACE

	select ARCH_WANT_OPTIONAL_GPIOLIB

	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

	select RTC_CLASS

	select RTC_DRV_M48T59

	select HAVE_IRQ_WORK

arch/sparc/include/asm/atomic_64.h

+3 −1
Original line number Diff line number Diff line 
/* atomic.h: Thankfully the V9 is at least reasonable for this

 *           stuff.

 *

 * Copyright (C) 1996, 1997, 2000 David S. Miller (davem@redhat.com)

 * Copyright (C) 1996, 1997, 2000, 2012 David S. Miller (davem@redhat.com)

 */



#ifndef __ARCH_SPARC64_ATOMIC__
@@ -106,6 +106,8 @@ static inline long atomic64_add_unless(atomic64_t *v, long a, long u) 


#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)



extern long atomic64_dec_if_positive(atomic64_t *v);



/* Atomic operations are already serializing */

#define smp_mb__before_atomic_dec()	barrier()

#define smp_mb__after_atomic_dec()	barrier()

arch/sparc/lib/atomic_64.S

+15 −1
Original line number Diff line number Diff line 
/* atomic.S: These things are too big to do inline.

 *

 * Copyright (C) 1999, 2007 David S. Miller (davem@davemloft.net)

 * Copyright (C) 1999, 2007 2012 David S. Miller (davem@davemloft.net)

 */



#include <linux/linkage.h>
@@ -117,3 +117,17 @@ ENTRY(atomic64_sub_ret) /* %o0 = decrement, %o1 = atomic_ptr */ 
	 sub	%g1, %o0, %o0

2:	BACKOFF_SPIN(%o2, %o3, 1b)

ENDPROC(atomic64_sub_ret)



ENTRY(atomic64_dec_if_positive) /* %o0 = atomic_ptr */

	BACKOFF_SETUP(%o2)

1:	ldx	[%o0], %g1

	brlez,pn %g1, 3f

	 sub	%g1, 1, %g7

	casx	[%o0], %g1, %g7

	cmp	%g1, %g7

	bne,pn	%xcc, BACKOFF_LABEL(2f, 1b)

	 nop

3:	retl

	 sub	%g1, 1, %o0

2:	BACKOFF_SPIN(%o2, %o3, 1b)

ENDPROC(atomic64_dec_if_positive)

arch/sparc/lib/ksyms.c

+1 −0
Original line number Diff line number Diff line
@@ -116,6 +116,7 @@ EXPORT_SYMBOL(atomic64_add); 
EXPORT_SYMBOL(atomic64_add_ret);

EXPORT_SYMBOL(atomic64_sub);

EXPORT_SYMBOL(atomic64_sub_ret);

EXPORT_SYMBOL(atomic64_dec_if_positive);



/* Atomic bit operations. */

EXPORT_SYMBOL(test_and_set_bit);