mirror of
https://github.com/torvalds/linux.git
synced 2025-11-04 10:40:15 +02:00
e986a0d6cb
The atomic bitops can actually be implemented pretty efficiently using the atomic_*() ops, rather than explicit use of spinlocks. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Cc: yamada.masahiro@socionext.com Link: https://lore.kernel.org/lkml/1529412794-17720-7-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_GENERIC_BITOPS_ATOMIC_H_
|
|
#define _ASM_GENERIC_BITOPS_ATOMIC_H_
|
|
|
|
#include <linux/atomic.h>
|
|
#include <linux/compiler.h>
|
|
#include <asm/barrier.h>
|
|
|
|
/*
|
|
* Implementation of atomic bitops using atomic-fetch ops.
|
|
* See Documentation/atomic_bitops.txt for details.
|
|
*/
|
|
|
|
static inline void set_bit(unsigned int nr, volatile unsigned long *p)
|
|
{
|
|
p += BIT_WORD(nr);
|
|
atomic_long_or(BIT_MASK(nr), (atomic_long_t *)p);
|
|
}
|
|
|
|
static inline void clear_bit(unsigned int nr, volatile unsigned long *p)
|
|
{
|
|
p += BIT_WORD(nr);
|
|
atomic_long_andnot(BIT_MASK(nr), (atomic_long_t *)p);
|
|
}
|
|
|
|
static inline void change_bit(unsigned int nr, volatile unsigned long *p)
|
|
{
|
|
p += BIT_WORD(nr);
|
|
atomic_long_xor(BIT_MASK(nr), (atomic_long_t *)p);
|
|
}
|
|
|
|
static inline int test_and_set_bit(unsigned int nr, volatile unsigned long *p)
|
|
{
|
|
long old;
|
|
unsigned long mask = BIT_MASK(nr);
|
|
|
|
p += BIT_WORD(nr);
|
|
if (READ_ONCE(*p) & mask)
|
|
return 1;
|
|
|
|
old = atomic_long_fetch_or(mask, (atomic_long_t *)p);
|
|
return !!(old & mask);
|
|
}
|
|
|
|
static inline int test_and_clear_bit(unsigned int nr, volatile unsigned long *p)
|
|
{
|
|
long old;
|
|
unsigned long mask = BIT_MASK(nr);
|
|
|
|
p += BIT_WORD(nr);
|
|
if (!(READ_ONCE(*p) & mask))
|
|
return 0;
|
|
|
|
old = atomic_long_fetch_andnot(mask, (atomic_long_t *)p);
|
|
return !!(old & mask);
|
|
}
|
|
|
|
static inline int test_and_change_bit(unsigned int nr, volatile unsigned long *p)
|
|
{
|
|
long old;
|
|
unsigned long mask = BIT_MASK(nr);
|
|
|
|
p += BIT_WORD(nr);
|
|
old = atomic_long_fetch_xor(mask, (atomic_long_t *)p);
|
|
return !!(old & mask);
|
|
}
|
|
|
|
#endif /* _ASM_GENERIC_BITOPS_ATOMIC_H */
|