WebSVN – HelenOS – Blame – //trunk/uspace/lib/libc/generic/fibril_sync.c

Rev	Author	Line No.	Line
1113	palkovsky	1	/*
4516	jermar	2	* Copyright (c) 2009 Jakub Jermar
1113	palkovsky	3	* All rights reserved.
		4	*
		5	* Redistribution and use in source and binary forms, with or without
		6	* modification, are permitted provided that the following conditions
		7	* are met:
		8	*
		9	* - Redistributions of source code must retain the above copyright
		10	* notice, this list of conditions and the following disclaimer.
		11	* - Redistributions in binary form must reproduce the above copyright
		12	* notice, this list of conditions and the following disclaimer in the
		13	* documentation and/or other materials provided with the distribution.
		14	* - The name of the author may not be used to endorse or promote products
		15	* derived from this software without specific prior written permission.
		16	*
		17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		27	*/
		28
1719	decky	29	/** @addtogroup libc
1653	cejka	30	* @{
		31	*/
		32	/** @file
		33	*/
		34
4516	jermar	35	#include <fibril_sync.h>
		36	#include <fibril.h>
		37	#include <async.h>
4509	decky	38	#include <adt/list.h>
1392	palkovsky	39	#include <futex.h>
		40	#include <assert.h>
1113	palkovsky	41
4516	jermar	42	void fibril_mutex_initialize(fibril_mutex_t *fm)
1129	palkovsky	43	{
4516	jermar	44	fm->counter = 1;
		45	list_initialize(&fm->waiters);
1129	palkovsky	46	}
		47
4516	jermar	48	void fibril_mutex_lock(fibril_mutex_t *fm)
1129	palkovsky	49	{
4516	jermar	50	futex_down(&async_futex);
		51	if (fm->counter-- <= 0) {
		52	fibril_t f = (fibril_t ) fibril_get_id();
		53	list_append(&f->link, &fm->waiters);
		54	fibril_switch(FIBRIL_TO_MANAGER);
		55	} else {
		56	futex_up(&async_futex);
		57	}
1129	palkovsky	58	}
		59
4516	jermar	60	bool fibril_mutex_trylock(fibril_mutex_t *fm)
1113	palkovsky	61	{
4516	jermar	62	bool locked = false;
1392	palkovsky	63
4516	jermar	64	futex_down(&async_futex);
		65	if (fm->counter > 0) {
		66	fm->counter--;
		67	locked = true;
1392	palkovsky	68	}
4516	jermar	69	futex_up(&async_futex);
1610	palkovsky	70
4516	jermar	71	return locked;
1113	palkovsky	72	}
		73
4516	jermar	74	void fibril_mutex_unlock(fibril_mutex_t *fm)
1113	palkovsky	75	{
4516	jermar	76	futex_down(&async_futex);
		77	assert(fm->counter <= 0);
		78	if (fm->counter++ < 0) {
		79	link_t *tmp;
		80	fibril_t *f;
		81
		82	assert(!list_empty(&fm->waiters));
		83	tmp = fm->waiters.next;
		84	f = list_get_instance(tmp, fibril_t, link);
		85	list_remove(&f->link);
		86	fibril_add_ready((fid_t) f);
1113	palkovsky	87	}
4516	jermar	88	futex_up(&async_futex);
1392	palkovsky	89	}
		90
4516	jermar	91	void fibril_rwlock_initialize(fibril_rwlock_t *frw)
1392	palkovsky	92	{
4526	jermar	93	frw->writers = 0;
		94	frw->readers = 0;
		95	list_initialize(&frw->waiters);
1392	palkovsky	96	}
1113	palkovsky	97
4516	jermar	98	void fibril_rwlock_read_lock(fibril_rwlock_t *frw)
1392	palkovsky	99	{
4526	jermar	100	futex_down(&async_futex);
		101	if (frw->writers) {
		102	fibril_t f = (fibril_t ) fibril_get_id();
		103	f->flags &= ~FIBRIL_WRITER;
		104	list_append(&f->link, &frw->waiters);
		105	fibril_switch(FIBRIL_TO_MANAGER);
		106	} else {
		107	frw->readers++;
		108	futex_up(&async_futex);
		109	}
1113	palkovsky	110	}
1392	palkovsky	111
4516	jermar	112	void fibril_rwlock_write_lock(fibril_rwlock_t *frw)
1392	palkovsky	113	{
4526	jermar	114	futex_down(&async_futex);
		115	if (frw->writers \|\| frw->readers) {
		116	fibril_t f = (fibril_t ) fibril_get_id();
		117	f->flags \|= FIBRIL_WRITER;
		118	list_append(&f->link, &frw->waiters);
		119	fibril_switch(FIBRIL_TO_MANAGER);
		120	} else {
		121	frw->writers++;
		122	futex_up(&async_futex);
		123	}
1392	palkovsky	124	}
1427	palkovsky	125
4526	jermar	126	static void _fibril_rwlock_common_unlock(fibril_rwlock_t *frw)
		127	{
		128	futex_down(&async_futex);
		129	assert(frw->readers \|\| (frw->writers == 1));
		130	if (frw->readers) {
		131	if (--frw->readers)
		132	goto out;
		133	} else {
		134	frw->writers--;
		135	}
		136
		137	assert(!frw->readers && !frw->writers);
		138
		139	while (!list_empty(&frw->waiters)) {
		140	link_t *tmp = frw->waiters.next;
		141	fibril_t *f = list_get_instance(tmp, fibril_t, link);
		142
		143	if (f->flags & FIBRIL_WRITER) {
		144	if (frw->readers)
		145	break;
		146	list_remove(&f->link);
		147	fibril_add_ready((fid_t) f);
		148	frw->writers++;
		149	break;
		150	} else {
		151	list_remove(&f->link);
		152	fibril_add_ready((fid_t) f);
		153	frw->readers++;
		154	}
		155	}
		156	out:
		157	futex_up(&async_futex);
		158	}
		159
4516	jermar	160	void fibril_rwlock_read_unlock(fibril_rwlock_t *frw)
1427	palkovsky	161	{
4526	jermar	162	_fibril_rwlock_common_unlock(frw);
1427	palkovsky	163	}
1610	palkovsky	164
4516	jermar	165	void fibril_rwlock_write_unlock(fibril_rwlock_t *frw)
1610	palkovsky	166	{
4526	jermar	167	_fibril_rwlock_common_unlock(frw);
1610	palkovsky	168	}
		169
1719	decky	170	/** @}
1653	cejka	171	*/

Subversion Repositories HelenOS

(root)//trunk/uspace/lib/libc/generic/fibril_sync.c – Rev 4526