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author | Ingo Molnar <mingo@elte.hu> | 2008-08-14 12:19:59 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-08-14 12:19:59 +0200 |
commit | 8d7ccaa545490cdffdfaff0842436a8dd85cf47b (patch) | |
tree | 8129b5907161bc6ae26deb3645ce1e280c5e1f51 /arch/ia64/include/asm/mutex.h | |
parent | b2139aa0eec330c711c5a279db361e5ef1178e78 (diff) | |
parent | 30a2f3c60a84092c8084dfe788b710f8d0768cd4 (diff) | |
download | linux-8d7ccaa545490cdffdfaff0842436a8dd85cf47b.tar.gz linux-8d7ccaa545490cdffdfaff0842436a8dd85cf47b.tar.bz2 linux-8d7ccaa545490cdffdfaff0842436a8dd85cf47b.zip |
Merge commit 'v2.6.27-rc3' into x86/prototypes
Conflicts:
include/asm-x86/dma-mapping.h
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/ia64/include/asm/mutex.h')
-rw-r--r-- | arch/ia64/include/asm/mutex.h | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/arch/ia64/include/asm/mutex.h b/arch/ia64/include/asm/mutex.h new file mode 100644 index 000000000000..bed73a643a56 --- /dev/null +++ b/arch/ia64/include/asm/mutex.h @@ -0,0 +1,92 @@ +/* + * ia64 implementation of the mutex fastpath. + * + * Copyright (C) 2006 Ken Chen <kenneth.w.chen@intel.com> + * + */ + +#ifndef _ASM_MUTEX_H +#define _ASM_MUTEX_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 + * @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 MUST leave the value lower than + * 1 even when the "1" assertion wasn't true. + */ +static inline void +__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) +{ + if (unlikely(ia64_fetchadd4_acq(count, -1) != 1)) + fail_fn(count); +} + +/** + * __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(ia64_fetchadd4_acq(count, -1) != 1)) + return fail_fn(count); + return 0; +} + +/** + * __mutex_fastpath_unlock - try to promote the count 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 count 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, then the + * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs + * to return 0 otherwise. + */ +static inline void +__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *)) +{ + int ret = ia64_fetchadd4_rel(count, 1); + if (unlikely(ret < 0)) + fail_fn(count); +} + +#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. + * + * If the architecture has no effective trylock variant, it should call the + * <fail_fn> spinlock-based trylock variant unconditionally. + */ +static inline int +__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *)) +{ + if (cmpxchg_acq(count, 1, 0) == 1) + return 1; + return 0; +} + +#endif |