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alpha: lock bitops

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Alpha can avoid one mb when acquiring a lock with test_and_set_bit_lock.

[bunk@kernel.org: alpha bitops.h must #include <asm/barrier.h>]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nick Piggin 2007-10-18 03:06:51 -07:00 committed by Linus Torvalds
parent 7c29ca5b8d
commit 44086d5286
1 changed files with 42 additions and 1 deletions
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43
include/asm-alpha/bitops.h
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@ -2,6 +2,7 @@
#define _ALPHA_BITOPS_H
#include <asm/compiler.h>
#include <asm/barrier.h>
/*
* Copyright 1994, Linus Torvalds.
@ -69,6 +70,13 @@ clear_bit(unsigned long nr, volatile void * addr)
:"Ir" (1UL << (nr & 31)), "m" (*m));
}
static inline void
clear_bit_unlock(unsigned long nr, volatile void * addr)
{
smp_mb();
clear_bit(nr, addr);
}
/*
* WARNING: non atomic version.
*/
@ -80,6 +88,13 @@ __clear_bit(unsigned long nr, volatile void * addr)
*m &= ~(1 << (nr & 31));
}
static inline void
__clear_bit_unlock(unsigned long nr, volatile void * addr)
{
smp_mb();
__clear_bit(nr, addr);
}
static inline void
change_bit(unsigned long nr, volatile void * addr)
{
@ -139,6 +154,33 @@ test_and_set_bit(unsigned long nr, volatile void *addr)
return oldbit != 0;
}
static inline int
test_and_set_bit_lock(unsigned long nr, volatile void *addr)
{
unsigned long oldbit;
unsigned long temp;
int *m = ((int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%4\n"
" and %0,%3,%2\n"
" bne %2,2f\n"
" xor %0,%3,%0\n"
" stl_c %0,%1\n"
" beq %0,3f\n"
"2:\n"
#ifdef CONFIG_SMP
" mb\n"
#endif
".subsection 2\n"
"3: br 1b\n"
".previous"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
return oldbit != 0;
}
/*
* WARNING: non atomic version.
*/
@ -376,7 +418,6 @@ static inline unsigned int hweight8(unsigned int w)
#else
#include <asm-generic/bitops/hweight.h>
#endif
#include <asm-generic/bitops/lock.h>
#endif /* __KERNEL__ */