Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Make <asm-x86/spinlock.h> use ACCESS_ONCE()
..instead of cooking up its own uglier local version of it.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+4
-14
+4
-14
include/asm-x86/spinlock.h
+4
-14
include/asm-x86/spinlock.h
···
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*/
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#ifdef CONFIG_X86_32
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-
typedef char _slock_t;
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-
# define LOCK_INS_DEC "decb"
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-
# define LOCK_INS_XCH "xchgb"
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# define LOCK_INS_MOV "movb"
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-
# define LOCK_INS_CMP "cmpb"
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# define LOCK_PTR_REG "a"
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#else
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typedef int _slock_t;
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# define LOCK_INS_DEC "decl"
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# define LOCK_INS_XCH "xchgl"
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# define LOCK_INS_MOV "movl"
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# define LOCK_INS_CMP "cmpl"
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# define LOCK_PTR_REG "D"
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#endif
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···
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#if (NR_CPUS < 256)
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static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
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{
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int tmp = *(volatile signed int *)(&(lock)->slock);
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+
int tmp = ACCESS_ONCE(lock->slock);
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return (((tmp >> 8) & 0xff) != (tmp & 0xff));
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}
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static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
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{
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int tmp = *(volatile signed int *)(&(lock)->slock);
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+
int tmp = ACCESS_ONCE(lock->slock);
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return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1;
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}
···
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#else
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static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
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{
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int tmp = *(volatile signed int *)(&(lock)->slock);
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+
int tmp = ACCESS_ONCE(lock->slock);
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return (((tmp >> 16) & 0xffff) != (tmp & 0xffff));
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}
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static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
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{
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-
int tmp = *(volatile signed int *)(&(lock)->slock);
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+
int tmp = ACCESS_ONCE(lock->slock);
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return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1;
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}