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author | davidxu <davidxu@FreeBSD.org> | 2012-03-21 07:16:58 +0000 |
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committer | davidxu <davidxu@FreeBSD.org> | 2012-03-21 07:16:58 +0000 |
commit | d02d68a8c81850f2b127b0364bb2bcf017db8c9f (patch) | |
tree | 2677654e24d040709ec04f6d55b09c5826636b1b /lib/libc | |
parent | fd4cb16e863d0646f3495a0cc56ac84b12e50806 (diff) | |
download | FreeBSD-src-d02d68a8c81850f2b127b0364bb2bcf017db8c9f.zip FreeBSD-src-d02d68a8c81850f2b127b0364bb2bcf017db8c9f.tar.gz |
Revert previous change. It is an incomplete change from old branch. :-(
Diffstat (limited to 'lib/libc')
-rw-r--r-- | lib/libc/gen/sem_new.c | 99 |
1 files changed, 39 insertions, 60 deletions
diff --git a/lib/libc/gen/sem_new.c b/lib/libc/gen/sem_new.c index f0d97e6..af64310 100644 --- a/lib/libc/gen/sem_new.c +++ b/lib/libc/gen/sem_new.c @@ -61,8 +61,7 @@ __weak_reference(_sem_unlink, sem_unlink); __weak_reference(_sem_wait, sem_wait); #define SEM_PREFIX "/tmp/SEMD" -#define SEM_MAGIC1 ((u_int32_t)0x73656d31) -#define SEM_MAGIC ((u_int32_t)0x73656d32) +#define SEM_MAGIC ((u_int32_t)0x73656d31) struct sem_nameinfo { int open_count; @@ -110,7 +109,7 @@ static inline int sem_check_validity(sem_t *sem) { - if (sem->_magic == SEM_MAGIC || sem->_magic == SEM_MAGIC1) + if (sem->_magic == SEM_MAGIC) return (0); else { errno = EINVAL; @@ -131,7 +130,7 @@ _sem_init(sem_t *sem, int pshared, unsigned int value) sem->_magic = SEM_MAGIC; sem->_kern._count = (u_int32_t)value; sem->_kern._has_waiters = 0; - sem->_kern._flags = (pshared ? USYNC_PROCESS_SHARED : 0) | SEM_VER2; + sem->_kern._flags = pshared ? USYNC_PROCESS_SHARED : 0; return (0); } @@ -208,7 +207,7 @@ _sem_open(const char *name, int flags, ...) tmp._magic = SEM_MAGIC; tmp._kern._has_waiters = 0; tmp._kern._count = value; - tmp._kern._flags = USYNC_PROCESS_SHARED | SEM_NAMED | SEM_VER2; + tmp._kern._flags = USYNC_PROCESS_SHARED | SEM_NAMED; if (_write(fd, &tmp, sizeof(tmp)) != sizeof(tmp)) { flock(fd, LOCK_UN); goto error; @@ -326,11 +325,20 @@ _sem_getvalue(sem_t * __restrict sem, int * __restrict sval) if (sem_check_validity(sem) != 0) return (-1); - *sval = (int)sem->_kern._count & ~SEM_WAITERS; + *sval = (int)sem->_kern._count; return (0); } static __inline int +usem_wake(struct _usem *sem) +{ + rmb(); + if (!sem->_has_waiters) + return (0); + return _umtx_op(sem, UMTX_OP_SEM_WAKE, 0, NULL, NULL); +} + +static __inline int usem_wait(struct _usem *sem, const struct timespec *abstime) { struct _umtx_time *tm_p, timeout; @@ -350,51 +358,48 @@ usem_wait(struct _usem *sem, const struct timespec *abstime) (void *)tm_size, __DECONST(void*, tm_p)); } -static inline int -_trywait(sem_t *sem) -{ - int count; - - if ((sem->_kern._flags & SEM_VER2) != 0) { - while (((count = sem->_kern._count) & ~SEM_WAITERS) > 0) { - if (atomic_cmpset_acq_int(&sem->_kern._count, count, count - 1)) - return (0); - } - } else { - while ((count = sem->_kern._count) > 0) { - if (atomic_cmpset_acq_int(&sem->_kern._count, count, count - 1)) - return (0); - } - } - return (EAGAIN); -} - int _sem_trywait(sem_t *sem) { - int status; + int val; if (sem_check_validity(sem) != 0) return (-1); - if ((status = _trywait(sem)) == 0) - return (0); - errno = status; + + while ((val = sem->_kern._count) > 0) { + if (atomic_cmpset_acq_int(&sem->_kern._count, val, val - 1)) + return (0); + } + errno = EAGAIN; return (-1); } +#define TIMESPEC_SUB(dst, src, val) \ + do { \ + (dst)->tv_sec = (src)->tv_sec - (val)->tv_sec; \ + (dst)->tv_nsec = (src)->tv_nsec - (val)->tv_nsec; \ + if ((dst)->tv_nsec < 0) { \ + (dst)->tv_sec--; \ + (dst)->tv_nsec += 1000000000; \ + } \ + } while (0) + + int _sem_timedwait(sem_t * __restrict sem, const struct timespec * __restrict abstime) { - int retval; + int val, retval; if (sem_check_validity(sem) != 0) return (-1); retval = 0; for (;;) { - if (_trywait(sem) == 0) - return (0); + while ((val = sem->_kern._count) > 0) { + if (atomic_cmpset_acq_int(&sem->_kern._count, val, val - 1)) + return (0); + } if (retval) { _pthread_testcancel(); @@ -433,36 +438,10 @@ _sem_wait(sem_t *sem) int _sem_post(sem_t *sem) { - int count; if (sem_check_validity(sem) != 0) return (-1); - if ((sem->_kern._flags & SEM_VER2) != 0) { - for (;;) { - count = sem->_kern._count; - if ((count & SEM_WAITERS) == 0) { - if (__predict_false(count == SEM_VALUE_MAX)) { - errno = ERANGE; - return (-1); - } - if (atomic_cmpset_rel_int(&sem->_kern._count, count, count+1)) - return (0); - } else { - return _umtx_op(&sem->_kern, UMTX_OP_SEM_WAKE, 0, NULL, NULL); - } - } - } else { - do { - count = sem->_kern._count; - if (__predict_false(count == SEM_VALUE_MAX)) { - errno = ERANGE; - return (-1); - } - } while (!atomic_cmpset_rel_int(&sem->_kern._count, count, count+1)); - rmb(); - if (!sem->_kern._has_waiters) - return (0); - return _umtx_op(&sem->_kern, UMTX_OP_SEM_WAKE, 0, NULL, NULL); - } + atomic_add_rel_int(&sem->_kern._count, 1); + return usem_wake(&sem->_kern); } |