MFC - Fix an errno leak in libthread_xu's calls to umtx.
[dragonfly.git] / lib / libthread_xu / thread / thr_umtx.c
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1/*-
2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
3 * Copyright (c) 2005 Matthew Dillon <dillon@backplane.com>
4 *
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 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
3db51647 28 * $DragonFly: src/lib/libthread_xu/thread/thr_umtx.c,v 1.4 2008/04/14 20:12:41 dillon Exp $
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29 */
30
31#include <assert.h>
32#include <errno.h>
33#include <unistd.h>
34#include <sys/time.h>
35
36#include "thr_private.h"
37
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38/*
39 * This function is used to acquire a contested lock.
40 */
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41int
42__thr_umtx_lock(volatile umtx_t *mtx, int timo)
43{
ec7c2f67 44 int v, errval, ret = 0;
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45
46 /* contested */
47 do {
48 v = *mtx;
49 if (v == 2 || atomic_cmpset_acq_int(mtx, 1, 2)) {
50 if (timo == 0)
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51 _umtx_sleep_err(mtx, 2, timo);
52 else if ( (errval = _umtx_sleep_err(mtx, 2, timo)) != 0) {
53 if (errval == EAGAIN) {
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54 if (atomic_cmpset_acq_int(mtx, 0, 2))
55 ret = 0;
56 else
57 ret = ETIMEDOUT;
58 break;
59 }
60 }
71b3fa15 61 }
a8408233 62 } while (!atomic_cmpset_acq_int(mtx, 0, 2));
71b3fa15 63
a8408233 64 return (ret);
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65}
66
67void
68__thr_umtx_unlock(volatile umtx_t *mtx)
69{
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70 int v;
71
72 for (;;) {
73 v = *mtx;
74 if (atomic_cmpset_acq_int(mtx, v, v-1)) {
75 if (v != 1) {
76 *mtx = 0;
ec7c2f67 77 _umtx_wakeup_err(mtx, 1);
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78 }
79 break;
80 }
71b3fa15 81 }
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82}
83
84int
85__thr_umtx_timedlock(volatile umtx_t *mtx, const struct timespec *timeout)
86{
87 struct timespec ts, ts2, ts3;
88 int timo, ret;
89
90 if ((timeout->tv_sec < 0) ||
91 (timeout->tv_sec == 0 && timeout->tv_nsec <= 0))
92 return (ETIMEDOUT);
93
94 /* XXX there should have MONO timer! */
95 clock_gettime(CLOCK_REALTIME, &ts);
96 TIMESPEC_ADD(&ts, &ts, timeout);
97 ts2 = *timeout;
98
99 for (;;) {
100 if (ts2.tv_nsec) {
101 timo = (int)(ts2.tv_nsec / 1000);
102 if (timo == 0)
103 timo = 1;
104 } else {
105 timo = 1000000;
106 }
107 ret = __thr_umtx_lock(mtx, timo);
108 if (ret != ETIMEDOUT)
109 break;
110 clock_gettime(CLOCK_REALTIME, &ts3);
111 TIMESPEC_SUB(&ts2, &ts, &ts3);
112 if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0)) {
113 ret = ETIMEDOUT;
114 break;
115 }
116 }
117 return (ret);
118}
119
120int
9219c44c 121_thr_umtx_wait(volatile umtx_t *mtx, int exp, const struct timespec *timeout,
3db51647 122 int clockid)
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123{
124 struct timespec ts, ts2, ts3;
ec7c2f67 125 int timo, errval, ret = 0;
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126
127 if (*mtx != exp)
128 return (0);
129
130 if (timeout == NULL) {
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131 while ( (errval = _umtx_sleep_err(mtx, exp, 10000000)) < 0) {
132 if (errval == EBUSY)
3db51647 133 break;
ec7c2f67 134 if (errval == EINTR) {
71b3fa15 135 ret = EINTR;
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136 break;
137 }
ec7c2f67 138 if (errval == ETIMEDOUT || errval == EWOULDBLOCK) {
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139 if (*mtx != exp) {
140 fprintf(stderr, "thr_umtx_wait: FAULT VALUE CHANGE %d -> %d oncond %p\n", exp, *mtx, mtx);
141 }
142 }
143 if (*mtx != exp)
144 return(0);
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145 }
146 return (ret);
147 }
148
149 if ((timeout->tv_sec < 0) ||
150 (timeout->tv_sec == 0 && timeout->tv_nsec <= 0))
151 return (ETIMEDOUT);
152
9219c44c 153 clock_gettime(clockid, &ts);
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154 TIMESPEC_ADD(&ts, &ts, timeout);
155 ts2 = *timeout;
156
157 for (;;) {
158 if (ts2.tv_nsec) {
159 timo = (int)(ts2.tv_nsec / 1000);
160 if (timo == 0)
161 timo = 1;
162 } else {
163 timo = 1000000;
164 }
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165 if ( (errval = _umtx_sleep_err(mtx, exp, timo)) < 0) {
166 if (errval == EBUSY) {
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167 ret = 0;
168 break;
ec7c2f67 169 } else if (errval == EINTR) {
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170 ret = EINTR;
171 break;
172 }
173 }
9219c44c 174 clock_gettime(clockid, &ts3);
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175 TIMESPEC_SUB(&ts2, &ts, &ts3);
176 if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0)) {
177 ret = ETIMEDOUT;
178 break;
179 }
180 }
181 return (ret);
182}
183
184void _thr_umtx_wake(volatile umtx_t *mtx, int count)
185{
ec7c2f67 186 _umtx_wakeup_err(mtx, count);
71b3fa15 187}