WebSVN – HelenOS-historic – Diff – /uspace/trunk/libc/generic/futex.c



    atomic_set(futex, val);
}
 
int futex_down(atomic_t *futex)
{
    return futex_down_timeout(futex, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE);
}
 
int futex_trydown(atomic_t *futex)
{
    return futex_down_timeout(futex, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NON_BLOCKING);
}
 
/** Try to down the futex.
 *
 * @param futex Futex.
 * @param usec Microseconds to wait. Zero value means sleep without timeout.
 * @param flags Select mode of operation. See comment for waitq_sleep_timeout().
 *
 * @return ENOENT if there is no such virtual address. One of ESYNCH_OK_ATOMIC
 *     and ESYNCH_OK_BLOCKED on success or ESYNCH_TIMEOUT if the lock was
 *     not acquired because of a timeout or ESYNCH_WOULD_BLOCK if the
 *     operation could not be carried out atomically (if requested so).
 */
int futex_down_timeout(atomic_t *futex, uint32_t usec, int flags)
{
    int rc;
   
    while (atomic_predec(futex) < 0) {
        rc = __SYSCALL3(SYS_FUTEX_SLEEP, (sysarg_t) &futex->count, (sysarg_t) usec, (sysarg_t) flags);
       
        switch (rc) {
        case ESYNCH_OK_ATOMIC:
            /*
             * Because of a race condition between timeout and futex_up()

Subversion Repositories HelenOS-historic

(root)/uspace/trunk/libc/generic/futex.c @ 1653 – Rev 1152 → 1503

Rev 1152		Rev 1503
Line 79...		Line 79...
79	atomic_set(futex, val);	79	atomic_set(futex, val);
80	}	80	}
81		81
82	int futex_down(atomic_t *futex)	82	int futex_down(atomic_t *futex)
83	{	83	{
84	return futex_down_timeout(futex, SYNCH_NO_TIMEOUT, SYNCH_BLOCKING);	84	return futex_down_timeout(futex, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE);
85	}	85	}
86		86
87	int futex_trydown(atomic_t *futex)	87	int futex_trydown(atomic_t *futex)
88	{	88	{
89	return futex_down_timeout(futex, SYNCH_NO_TIMEOUT, SYNCH_NON_BLOCKING);	89	return futex_down_timeout(futex, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NON_BLOCKING);
90	}	90	}
91		91
92	/** Try to down the futex.	92	/** Try to down the futex.
93	*	93	*
94	* @param futex Futex.	94	* @param futex Futex.
95	* @param usec Microseconds to wait. Zero value means sleep without timeout.	95	* @param usec Microseconds to wait. Zero value means sleep without timeout.
96	* @param trydown If usec is zero and trydown is non-zero, only conditional	96	* @param flags Select mode of operation. See comment for waitq_sleep_timeout().
97	*	97	*
98	* @return ENOENT if there is no such virtual address. One of ESYNCH_OK_ATOMIC	98	* @return ENOENT if there is no such virtual address. One of ESYNCH_OK_ATOMIC
99	* and ESYNCH_OK_BLOCKED on success or ESYNCH_TIMEOUT if the lock was	99	* and ESYNCH_OK_BLOCKED on success or ESYNCH_TIMEOUT if the lock was
100	* not acquired because of a timeout or ESYNCH_WOULD_BLOCK if the	100	* not acquired because of a timeout or ESYNCH_WOULD_BLOCK if the
101	* operation could not be carried out atomically (if requested so).	101	* operation could not be carried out atomically (if requested so).
102	*/	102	*/
103	int futex_down_timeout(atomic_t *futex, uint32_t usec, int trydown)	103	int futex_down_timeout(atomic_t *futex, uint32_t usec, int flags)
104	{	104	{
105	int rc;	105	int rc;
106		106
107	while (atomic_predec(futex) < 0) {	107	while (atomic_predec(futex) < 0) {
108	rc = __SYSCALL3(SYS_FUTEX_SLEEP, (sysarg_t) &futex->count, (sysarg_t) usec, (sysarg_t) trydown);	108	rc = __SYSCALL3(SYS_FUTEX_SLEEP, (sysarg_t) &futex->count, (sysarg_t) usec, (sysarg_t) flags);
109		109
110	switch (rc) {	110	switch (rc) {
111	case ESYNCH_OK_ATOMIC:	111	case ESYNCH_OK_ATOMIC:
112	/*	112	/*
113	* Because of a race condition between timeout and futex_up()	113	* Because of a race condition between timeout and futex_up()