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Diffstat (limited to 'include/asm-x86/mutex_32.h')
| -rw-r--r-- | include/asm-x86/mutex_32.h | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/include/asm-x86/mutex_32.h b/include/asm-x86/mutex_32.h deleted file mode 100644 index 73e928ef5f0..00000000000 --- a/include/asm-x86/mutex_32.h +++ /dev/null @@ -1,125 +0,0 @@ -/* - * Assembly implementation of the mutex fastpath, based on atomic - * decrement/increment. - * - * started by Ingo Molnar: - * - * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> - */ -#ifndef _ASM_MUTEX_H -#define _ASM_MUTEX_H - -#include <asm/alternative.h> - -/** - * __mutex_fastpath_lock - try to take the lock by moving the count - * from 1 to a 0 value - * @count: pointer of type atomic_t - * @fn: function to call if the original value was not 1 - * - * Change the count from 1 to a value lower than 1, and call <fn> if it - * wasn't 1 originally. This function MUST leave the value lower than 1 - * even when the "1" assertion wasn't true. - */ -#define __mutex_fastpath_lock(count, fail_fn) \ -do { \ - unsigned int dummy; \ - \ - typecheck(atomic_t *, count); \ - typecheck_fn(void (*)(atomic_t *), fail_fn); \ - \ - asm volatile(LOCK_PREFIX " decl (%%eax)\n" \ - " jns 1f \n" \ - " call " #fail_fn "\n" \ - "1:\n" \ - : "=a" (dummy) \ - : "a" (count) \ - : "memory", "ecx", "edx"); \ -} while (0) - - -/** - * __mutex_fastpath_lock_retval - try to take the lock by moving the count - * from 1 to a 0 value - * @count: pointer of type atomic_t - * @fail_fn: function to call if the original value was not 1 - * - * Change the count from 1 to a value lower than 1, and call <fail_fn> if it - * wasn't 1 originally. This function returns 0 if the fastpath succeeds, - * or anything the slow path function returns - */ -static inline int __mutex_fastpath_lock_retval(atomic_t *count, - int (*fail_fn)(atomic_t *)) -{ - if (unlikely(atomic_dec_return(count) < 0)) - return fail_fn(count); - else - return 0; -} - -/** - * __mutex_fastpath_unlock - try to promote the mutex from 0 to 1 - * @count: pointer of type atomic_t - * @fail_fn: function to call if the original value was not 0 - * - * try to promote the mutex from 0 to 1. if it wasn't 0, call <fail_fn>. - * In the failure case, this function is allowed to either set the value - * to 1, or to set it to a value lower than 1. - * - * If the implementation sets it to a value of lower than 1, the - * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs - * to return 0 otherwise. - */ -#define __mutex_fastpath_unlock(count, fail_fn) \ -do { \ - unsigned int dummy; \ - \ - typecheck(atomic_t *, count); \ - typecheck_fn(void (*)(atomic_t *), fail_fn); \ - \ - asm volatile(LOCK_PREFIX " incl (%%eax)\n" \ - " jg 1f\n" \ - " call " #fail_fn "\n" \ - "1:\n" \ - : "=a" (dummy) \ - : "a" (count) \ - : "memory", "ecx", "edx"); \ -} while (0) - -#define __mutex_slowpath_needs_to_unlock() 1 - -/** - * __mutex_fastpath_trylock - try to acquire the mutex, without waiting - * - * @count: pointer of type atomic_t - * @fail_fn: fallback function - * - * Change the count from 1 to a value lower than 1, and return 0 (failure) - * if it wasn't 1 originally, or return 1 (success) otherwise. This function - * MUST leave the value lower than 1 even when the "1" assertion wasn't true. - * Additionally, if the value was < 0 originally, this function must not leave - * it to 0 on failure. - */ -static inline int __mutex_fastpath_trylock(atomic_t *count, - int (*fail_fn)(atomic_t *)) -{ - /* - * We have two variants here. The cmpxchg based one is the best one - * because it never induce a false contention state. It is included - * here because architectures using the inc/dec algorithms over the - * xchg ones are much more likely to support cmpxchg natively. - * - * If not we fall back to the spinlock based variant - that is - * just as efficient (and simpler) as a 'destructive' probing of - * the mutex state would be. - */ -#ifdef __HAVE_ARCH_CMPXCHG - if (likely(atomic_cmpxchg(count, 1, 0) == 1)) - return 1; - return 0; -#else - return fail_fn(count); -#endif -} - -#endif |