C++ (Cpp) check_simple_locks Examples

Example #1

File: lock.c Project: 0xffea/gnumach

/*
 *	Routine:	lock_try_read_to_write
 *	Function:
 *		Improves a read-only lock to one with
 *		write permission.  If another reader has
 *		already requested an upgrade to a write lock,
 *		the read lock is still held upon return.
 *
 *		Returns FALSE if the upgrade *failed*.
 */
boolean_t lock_try_read_to_write(
	register lock_t	l)
{
	check_simple_locks();
	simple_lock(&l->interlock);

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock
		 */
		l->read_count--;
		l->recursion_depth++;
		simple_unlock(&l->interlock);
		return TRUE;
	}

	if (l->want_upgrade) {
		simple_unlock(&l->interlock);
		return FALSE;
	}
	l->want_upgrade = TRUE;
	l->read_count--;

	while (l->read_count != 0) {
		l->waiting = TRUE;
		thread_sleep(l,
			simple_lock_addr(l->interlock), FALSE);
		simple_lock(&l->interlock);
	}

	simple_unlock(&l->interlock);
	return TRUE;
}

Example #2

File: lock.c Project: 0xffea/gnumach

void lock_write(
	register lock_t	l)
{
	register int	i;

	check_simple_locks();
	simple_lock(&l->interlock);

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock.
		 */
		l->recursion_depth++;
		simple_unlock(&l->interlock);
		return;
	}

	/*
	 *	Try to acquire the want_write bit.
	 */
	while (l->want_write) {
		if ((i = lock_wait_time) > 0) {
			simple_unlock(&l->interlock);
			while (--i > 0 && l->want_write)
				continue;
			simple_lock(&l->interlock);
		}

		if (l->can_sleep && l->want_write) {
			l->waiting = TRUE;
			thread_sleep(l,
				simple_lock_addr(l->interlock), FALSE);
			simple_lock(&l->interlock);
		}
	}
	l->want_write = TRUE;

	/* Wait for readers (and upgrades) to finish */

	while ((l->read_count != 0) || l->want_upgrade) {
		if ((i = lock_wait_time) > 0) {
			simple_unlock(&l->interlock);
			while (--i > 0 && (l->read_count != 0 ||
					l->want_upgrade))
				continue;
			simple_lock(&l->interlock);
		}

		if (l->can_sleep && (l->read_count != 0 || l->want_upgrade)) {
			l->waiting = TRUE;
			thread_sleep(l,
				simple_lock_addr(l->interlock), FALSE);
			simple_lock(&l->interlock);
		}
	}
	simple_unlock(&l->interlock);
}

Example #3

File: lock.c Project: 0xffea/gnumach

/*
 *	Routine:	lock_read_to_write
 *	Function:
 *		Improves a read-only lock to one with
 *		write permission.  If another reader has
 *		already requested an upgrade to a write lock,
 *		no lock is held upon return.
 *
 *		Returns TRUE if the upgrade *failed*.
 */
boolean_t lock_read_to_write(
	register lock_t	l)
{
	register int	i;

	check_simple_locks();
	simple_lock(&l->interlock);

	l->read_count--;

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock.
		 */
		l->recursion_depth++;
		simple_unlock(&l->interlock);
		return(FALSE);
	}

	if (l->want_upgrade) {
		/*
		 *	Someone else has requested upgrade.
		 *	Since we've released a read lock, wake
		 *	him up.
		 */
		if (l->waiting && (l->read_count == 0)) {
			l->waiting = FALSE;
			thread_wakeup(l);
		}

		simple_unlock(&l->interlock);
		return TRUE;
	}

	l->want_upgrade = TRUE;

	while (l->read_count != 0) {
		if ((i = lock_wait_time) > 0) {
			simple_unlock(&l->interlock);
			while (--i > 0 && l->read_count != 0)
				continue;
			simple_lock(&l->interlock);
		}

		if (l->can_sleep && l->read_count != 0) {
			l->waiting = TRUE;
			thread_sleep(l,
				simple_lock_addr(l->interlock), FALSE);
			simple_lock(&l->interlock);
		}
	}

	simple_unlock(&l->interlock);
	return FALSE;
}

Example #4

File: ipc_port.c Project: outbackdingo/uBSD

void
ipc_port_release_send(
	ipc_port_t	port)
{
	ipc_port_t nsrequest = IP_NULL;
	mach_port_mscount_t mscount;

	assert(IP_VALID(port));

	ip_lock(port);

	if (!ip_active(port)) {
		ip_unlock(port);
		ip_release(port);
		return;
	}

	assert(port->ip_srights > 0);

	if (--port->ip_srights == 0 &&
	    port->ip_nsrequest != IP_NULL) {
		nsrequest = port->ip_nsrequest;
		port->ip_nsrequest = IP_NULL;
		mscount = port->ip_mscount;
		ip_unlock(port);
		ipc_notify_no_senders(nsrequest, mscount);
#if 0		
		/*
		 * Check that there are no other locks taken, because
		 * [norma_]ipc_notify_no_senders routines may block.
		 */
		check_simple_locks();
#endif		
	} else
		ip_unlock(port);
	ip_release(port);
}

Example #5

File: lock.c Project: 0xffea/gnumach

void lock_read(
	register lock_t	l)
{
	register int	i;

	check_simple_locks();
	simple_lock(&l->interlock);

	if (l->thread == current_thread()) {
		/*
		 *	Recursive lock.
		 */
		l->read_count++;
		simple_unlock(&l->interlock);
		return;
	}

	while (l->want_write || l->want_upgrade) {
		if ((i = lock_wait_time) > 0) {
			simple_unlock(&l->interlock);
			while (--i > 0 && (l->want_write || l->want_upgrade))
				continue;
			simple_lock(&l->interlock);
		}

		if (l->can_sleep && (l->want_write || l->want_upgrade)) {
			l->waiting = TRUE;
			thread_sleep(l,
				simple_lock_addr(l->interlock), FALSE);
			simple_lock(&l->interlock);
		}
	}

	l->read_count++;
	simple_unlock(&l->interlock);
}