1 /*
2 * SPDX-License-Identifier: BSD-3-Clause
3 * Copyright 2015 Intel Corporation.
4 * Copyright 2012 Hasan Alayli <[email protected]>
5 */
6
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include <stdint.h>
11 #include <stddef.h>
12 #include <limits.h>
13 #include <inttypes.h>
14 #include <unistd.h>
15 #include <pthread.h>
16 #include <fcntl.h>
17 #include <sys/time.h>
18 #include <sys/mman.h>
19 #include <errno.h>
20
21 #include <rte_log.h>
22 #include <rte_common.h>
23
24 #include "lthread_api.h"
25 #include "lthread_diag_api.h"
26 #include "lthread_diag.h"
27 #include "lthread_int.h"
28 #include "lthread_sched.h"
29 #include "lthread_queue.h"
30 #include "lthread_objcache.h"
31 #include "lthread_timer.h"
32 #include "lthread_mutex.h"
33 #include "lthread_cond.h"
34
35 /*
36 * Create a condition variable
37 */
38 int
lthread_cond_init(char * name,struct lthread_cond ** cond,__rte_unused const struct lthread_condattr * attr)39 lthread_cond_init(char *name, struct lthread_cond **cond,
40 __rte_unused const struct lthread_condattr *attr)
41 {
42 struct lthread_cond *c;
43
44 if (cond == NULL)
45 return POSIX_ERRNO(EINVAL);
46
47 /* allocate a condition variable from cache */
48 c = _lthread_objcache_alloc((THIS_SCHED)->cond_cache);
49
50 if (c == NULL)
51 return POSIX_ERRNO(EAGAIN);
52
53 c->blocked = _lthread_queue_create("blocked");
54 if (c->blocked == NULL) {
55 _lthread_objcache_free((THIS_SCHED)->cond_cache, (void *)c);
56 return POSIX_ERRNO(EAGAIN);
57 }
58
59 if (name == NULL)
60 strncpy(c->name, "no name", sizeof(c->name));
61 else
62 strncpy(c->name, name, sizeof(c->name));
63 c->name[sizeof(c->name)-1] = 0;
64
65 c->root_sched = THIS_SCHED;
66
67 (*cond) = c;
68 DIAG_CREATE_EVENT((*cond), LT_DIAG_COND_CREATE);
69 return 0;
70 }
71
72 /*
73 * Destroy a condition variable
74 */
lthread_cond_destroy(struct lthread_cond * c)75 int lthread_cond_destroy(struct lthread_cond *c)
76 {
77 if (c == NULL) {
78 DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EINVAL));
79 return POSIX_ERRNO(EINVAL);
80 }
81
82 /* try to free it */
83 if (_lthread_queue_destroy(c->blocked) < 0) {
84 /* queue in use */
85 DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EBUSY));
86 return POSIX_ERRNO(EBUSY);
87 }
88
89 /* okay free it */
90 _lthread_objcache_free(c->root_sched->cond_cache, c);
91 DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, 0);
92 return 0;
93 }
94
95 /*
96 * Wait on a condition variable
97 */
lthread_cond_wait(struct lthread_cond * c,__rte_unused uint64_t reserved)98 int lthread_cond_wait(struct lthread_cond *c, __rte_unused uint64_t reserved)
99 {
100 struct lthread *lt = THIS_LTHREAD;
101
102 if (c == NULL) {
103 DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, POSIX_ERRNO(EINVAL));
104 return POSIX_ERRNO(EINVAL);
105 }
106
107
108 DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, 0);
109
110 /* queue the current thread in the blocked queue
111 * this will be written when we return to the scheduler
112 * to ensure that the current thread context is saved
113 * before any signal could result in it being dequeued and
114 * resumed
115 */
116 lt->pending_wr_queue = c->blocked;
117 _suspend();
118
119 /* the condition happened */
120 return 0;
121 }
122
123 /*
124 * Signal a condition variable
125 * attempt to resume any blocked thread
126 */
lthread_cond_signal(struct lthread_cond * c)127 int lthread_cond_signal(struct lthread_cond *c)
128 {
129 struct lthread *lt;
130
131 if (c == NULL) {
132 DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, POSIX_ERRNO(EINVAL));
133 return POSIX_ERRNO(EINVAL);
134 }
135
136 lt = _lthread_queue_remove(c->blocked);
137
138 if (lt != NULL) {
139 /* okay wake up this thread */
140 DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, lt);
141 _ready_queue_insert((struct lthread_sched *)lt->sched, lt);
142 }
143 return 0;
144 }
145
146 /*
147 * Broadcast a condition variable
148 */
lthread_cond_broadcast(struct lthread_cond * c)149 int lthread_cond_broadcast(struct lthread_cond *c)
150 {
151 struct lthread *lt;
152
153 if (c == NULL) {
154 DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, POSIX_ERRNO(EINVAL));
155 return POSIX_ERRNO(EINVAL);
156 }
157
158 DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
159 do {
160 /* drain the queue waking everybody */
161 lt = _lthread_queue_remove(c->blocked);
162
163 if (lt != NULL) {
164 DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, lt);
165 /* wake up */
166 _ready_queue_insert((struct lthread_sched *)lt->sched,
167 lt);
168 }
169 } while (!_lthread_queue_empty(c->blocked));
170 _reschedule();
171 DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
172 return 0;
173 }
174
175 /*
176 * return the diagnostic ref val stored in a condition var
177 */
178 uint64_t
lthread_cond_diag_ref(struct lthread_cond * c)179 lthread_cond_diag_ref(struct lthread_cond *c)
180 {
181 if (c == NULL)
182 return 0;
183 return c->diag_ref;
184 }
185