1/*-
2 *   BSD LICENSE
3 *
4 *   Copyright(c) 2015 Intel Corporation. All rights reserved.
5 *   All rights reserved.
6 *
7 *   Redistribution and use in source and binary forms, with or without
8 *   modification, are permitted provided that the following conditions
9 *   are met:
10 *
11 *     * Redistributions of source code must retain the above copyright
12 *       notice, this list of conditions and the following disclaimer.
13 *     * Redistributions in binary form must reproduce the above copyright
14 *       notice, this list of conditions and the following disclaimer in
15 *       the documentation and/or other materials provided with the
16 *       distribution.
17 *     * Neither the name of Intel Corporation nor the names of its
18 *       contributors may be used to endorse or promote products derived
19 *       from this software without specific prior written permission.
20 *
21 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34/*
35 * Some portions of this software may have been derived from the
36 * https://github.com/halayli/lthread which carrys the following license.
37 *
38 * Copyright (C) 2012, Hasan Alayli <halayli@gmail.com>
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 *    notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 *    notice, this list of conditions and the following disclaimer in the
47 *    documentation and/or other materials provided with the distribution.
48 *
49 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 */
61
62#include <stdio.h>
63#include <stdlib.h>
64#include <string.h>
65#include <stdint.h>
66#include <stddef.h>
67#include <limits.h>
68#include <inttypes.h>
69#include <unistd.h>
70#include <pthread.h>
71#include <fcntl.h>
72#include <sys/time.h>
73#include <sys/mman.h>
74#include <errno.h>
75
76#include <rte_log.h>
77#include <rte_common.h>
78
79#include "lthread_api.h"
80#include "lthread_diag_api.h"
81#include "lthread_diag.h"
82#include "lthread_int.h"
83#include "lthread_sched.h"
84#include "lthread_queue.h"
85#include "lthread_objcache.h"
86#include "lthread_timer.h"
87#include "lthread_mutex.h"
88#include "lthread_cond.h"
89
90/*
91 * Create a condition variable
92 */
93int
94lthread_cond_init(char *name, struct lthread_cond **cond,
95		  __rte_unused const struct lthread_condattr *attr)
96{
97	struct lthread_cond *c;
98
99	if (cond == NULL)
100		return POSIX_ERRNO(EINVAL);
101
102	/* allocate a condition variable from cache */
103	c = _lthread_objcache_alloc((THIS_SCHED)->cond_cache);
104
105	if (c == NULL)
106		return POSIX_ERRNO(EAGAIN);
107
108	c->blocked = _lthread_queue_create("blocked");
109	if (c->blocked == NULL) {
110		_lthread_objcache_free((THIS_SCHED)->cond_cache, (void *)c);
111		return POSIX_ERRNO(EAGAIN);
112	}
113
114	if (name == NULL)
115		strncpy(c->name, "no name", sizeof(c->name));
116	else
117		strncpy(c->name, name, sizeof(c->name));
118	c->name[sizeof(c->name)-1] = 0;
119
120	c->root_sched = THIS_SCHED;
121
122	(*cond) = c;
123	DIAG_CREATE_EVENT((*cond), LT_DIAG_COND_CREATE);
124	return 0;
125}
126
127/*
128 * Destroy a condition variable
129 */
130int lthread_cond_destroy(struct lthread_cond *c)
131{
132	if (c == NULL) {
133		DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EINVAL));
134		return POSIX_ERRNO(EINVAL);
135	}
136
137	/* try to free it */
138	if (_lthread_queue_destroy(c->blocked) < 0) {
139		/* queue in use */
140		DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EBUSY));
141		return POSIX_ERRNO(EBUSY);
142	}
143
144	/* okay free it */
145	_lthread_objcache_free(c->root_sched->cond_cache, c);
146	DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, 0);
147	return 0;
148}
149
150/*
151 * Wait on a condition variable
152 */
153int lthread_cond_wait(struct lthread_cond *c, __rte_unused uint64_t reserved)
154{
155	struct lthread *lt = THIS_LTHREAD;
156
157	if (c == NULL) {
158		DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, POSIX_ERRNO(EINVAL));
159		return POSIX_ERRNO(EINVAL);
160	}
161
162
163	DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, 0);
164
165	/* queue the current thread in the blocked queue
166	 * this will be written when we return to the scheduler
167	 * to ensure that the current thread context is saved
168	 * before any signal could result in it being dequeued and
169	 * resumed
170	 */
171	lt->pending_wr_queue = c->blocked;
172	_suspend();
173
174	/* the condition happened */
175	return 0;
176}
177
178/*
179 * Signal a condition variable
180 * attempt to resume any blocked thread
181 */
182int lthread_cond_signal(struct lthread_cond *c)
183{
184	struct lthread *lt;
185
186	if (c == NULL) {
187		DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, POSIX_ERRNO(EINVAL));
188		return POSIX_ERRNO(EINVAL);
189	}
190
191	lt = _lthread_queue_remove(c->blocked);
192
193	if (lt != NULL) {
194		/* okay wake up this thread */
195		DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, lt);
196		_ready_queue_insert((struct lthread_sched *)lt->sched, lt);
197	}
198	return 0;
199}
200
201/*
202 * Broadcast a condition variable
203 */
204int lthread_cond_broadcast(struct lthread_cond *c)
205{
206	struct lthread *lt;
207
208	if (c == NULL) {
209		DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, POSIX_ERRNO(EINVAL));
210		return POSIX_ERRNO(EINVAL);
211	}
212
213	DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
214	do {
215		/* drain the queue waking everybody */
216		lt = _lthread_queue_remove(c->blocked);
217
218		if (lt != NULL) {
219			DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, lt);
220			/* wake up */
221			_ready_queue_insert((struct lthread_sched *)lt->sched,
222					    lt);
223		}
224	} while (!_lthread_queue_empty(c->blocked));
225	_reschedule();
226	DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
227	return 0;
228}
229
230/*
231 * return the diagnostic ref val stored in a condition var
232 */
233uint64_t
234lthread_cond_diag_ref(struct lthread_cond *c)
235{
236	if (c == NULL)
237		return 0;
238	return c->diag_ref;
239}
240