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1 | /* |
1 | /* |
2 | * Copyright (c) 2001-2004 Jakub Jermar |
2 | * Copyright (c) 2001-2004 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
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 |
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. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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 |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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 |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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 |
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. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | /** @addtogroup sync |
29 | /** @addtogroup sync |
30 | * @{ |
30 | * @{ |
31 | */ |
31 | */ |
32 | 32 | ||
33 | /** |
33 | /** |
34 | * @file |
34 | * @file |
35 | * @brief Wait queue. |
35 | * @brief Wait queue. |
36 | * |
36 | * |
37 | * Wait queue is the basic synchronization primitive upon which all |
37 | * Wait queue is the basic synchronization primitive upon which all |
38 | * other synchronization primitives build. |
38 | * other synchronization primitives build. |
39 | * |
39 | * |
40 | * It allows threads to wait for an event in first-come, first-served |
40 | * It allows threads to wait for an event in first-come, first-served |
41 | * fashion. Conditional operation as well as timeouts and interruptions |
41 | * fashion. Conditional operation as well as timeouts and interruptions |
42 | * are supported. |
42 | * are supported. |
43 | */ |
43 | */ |
44 | 44 | ||
45 | #include <synch/waitq.h> |
45 | #include <synch/waitq.h> |
46 | #include <synch/synch.h> |
46 | #include <synch/synch.h> |
47 | #include <synch/spinlock.h> |
47 | #include <synch/spinlock.h> |
48 | #include <proc/thread.h> |
48 | #include <proc/thread.h> |
49 | #include <proc/scheduler.h> |
49 | #include <proc/scheduler.h> |
50 | #include <arch/asm.h> |
50 | #include <arch/asm.h> |
51 | #include <arch/types.h> |
51 | #include <arch/types.h> |
52 | #include <time/timeout.h> |
52 | #include <time/timeout.h> |
53 | #include <arch.h> |
53 | #include <arch.h> |
54 | #include <context.h> |
54 | #include <context.h> |
55 | #include <adt/list.h> |
55 | #include <adt/list.h> |
56 | 56 | ||
57 | static void waitq_timeouted_sleep(void *data); |
57 | static void waitq_timeouted_sleep(void *data); |
58 | 58 | ||
59 | /** Initialize wait queue |
59 | /** Initialize wait queue |
60 | * |
60 | * |
61 | * Initialize wait queue. |
61 | * Initialize wait queue. |
62 | * |
62 | * |
63 | * @param wq Pointer to wait queue to be initialized. |
63 | * @param wq Pointer to wait queue to be initialized. |
64 | */ |
64 | */ |
65 | void waitq_initialize(waitq_t *wq) |
65 | void waitq_initialize(waitq_t *wq) |
66 | { |
66 | { |
67 | spinlock_initialize(&wq->lock, "waitq_lock"); |
67 | spinlock_initialize(&wq->lock, "waitq_lock"); |
68 | list_initialize(&wq->head); |
68 | list_initialize(&wq->head); |
69 | wq->missed_wakeups = 0; |
69 | wq->missed_wakeups = 0; |
70 | } |
70 | } |
71 | 71 | ||
72 | /** Handle timeout during waitq_sleep_timeout() call |
72 | /** Handle timeout during waitq_sleep_timeout() call |
73 | * |
73 | * |
74 | * This routine is called when waitq_sleep_timeout() timeouts. |
74 | * This routine is called when waitq_sleep_timeout() timeouts. |
75 | * Interrupts are disabled. |
75 | * Interrupts are disabled. |
76 | * |
76 | * |
77 | * It is supposed to try to remove 'its' thread from the wait queue; |
77 | * It is supposed to try to remove 'its' thread from the wait queue; |
78 | * it can eventually fail to achieve this goal when these two events |
78 | * it can eventually fail to achieve this goal when these two events |
79 | * overlap. In that case it behaves just as though there was no |
79 | * overlap. In that case it behaves just as though there was no |
80 | * timeout at all. |
80 | * timeout at all. |
81 | * |
81 | * |
82 | * @param data Pointer to the thread that called waitq_sleep_timeout(). |
82 | * @param data Pointer to the thread that called waitq_sleep_timeout(). |
83 | */ |
83 | */ |
84 | void waitq_timeouted_sleep(void *data) |
84 | void waitq_timeouted_sleep(void *data) |
85 | { |
85 | { |
86 | thread_t *t = (thread_t *) data; |
86 | thread_t *t = (thread_t *) data; |
87 | waitq_t *wq; |
87 | waitq_t *wq; |
88 | bool do_wakeup = false; |
88 | bool do_wakeup = false; |
89 | 89 | ||
90 | spinlock_lock(&threads_lock); |
90 | spinlock_lock(&threads_lock); |
91 | if (!thread_exists(t)) |
91 | if (!thread_exists(t)) |
92 | goto out; |
92 | goto out; |
93 | 93 | ||
94 | grab_locks: |
94 | grab_locks: |
95 | spinlock_lock(&t->lock); |
95 | spinlock_lock(&t->lock); |
96 | if ((wq = t->sleep_queue)) { /* assignment */ |
96 | if ((wq = t->sleep_queue)) { /* assignment */ |
97 | if (!spinlock_trylock(&wq->lock)) { |
97 | if (!spinlock_trylock(&wq->lock)) { |
98 | spinlock_unlock(&t->lock); |
98 | spinlock_unlock(&t->lock); |
99 | goto grab_locks; /* avoid deadlock */ |
99 | goto grab_locks; /* avoid deadlock */ |
100 | } |
100 | } |
101 | 101 | ||
102 | list_remove(&t->wq_link); |
102 | list_remove(&t->wq_link); |
103 | t->saved_context = t->sleep_timeout_context; |
103 | t->saved_context = t->sleep_timeout_context; |
104 | do_wakeup = true; |
104 | do_wakeup = true; |
105 | t->sleep_queue = NULL; |
105 | t->sleep_queue = NULL; |
106 | spinlock_unlock(&wq->lock); |
106 | spinlock_unlock(&wq->lock); |
107 | } |
107 | } |
108 | 108 | ||
109 | t->timeout_pending = false; |
109 | t->timeout_pending = false; |
110 | spinlock_unlock(&t->lock); |
110 | spinlock_unlock(&t->lock); |
111 | 111 | ||
112 | if (do_wakeup) |
112 | if (do_wakeup) |
113 | thread_ready(t); |
113 | thread_ready(t); |
114 | 114 | ||
115 | out: |
115 | out: |
116 | spinlock_unlock(&threads_lock); |
116 | spinlock_unlock(&threads_lock); |
117 | } |
117 | } |
118 | 118 | ||
- | 119 | /** Interrupt sleeping thread. |
|
- | 120 | * |
|
- | 121 | * This routine attempts to interrupt a thread from its sleep in a waitqueue. |
|
- | 122 | * If the thread is not found sleeping, no action is taken. |
|
- | 123 | * |
|
- | 124 | * @param t Thread to be interrupted. |
|
- | 125 | */ |
|
- | 126 | void waitq_interrupt_sleep(thread_t *t) |
|
- | 127 | { |
|
- | 128 | waitq_t *wq; |
|
- | 129 | bool do_wakeup = false; |
|
- | 130 | ipl_t ipl; |
|
- | 131 | ||
- | 132 | ipl = interrupts_disable(); |
|
- | 133 | spinlock_lock(&threads_lock); |
|
- | 134 | if (!thread_exists(t)) |
|
- | 135 | goto out; |
|
- | 136 | ||
- | 137 | grab_locks: |
|
- | 138 | spinlock_lock(&t->lock); |
|
- | 139 | if ((wq = t->sleep_queue)) { /* assignment */ |
|
- | 140 | if (!(t->sleep_interruptible)) { |
|
- | 141 | /* |
|
- | 142 | * The sleep cannot be interrupted. |
|
- | 143 | */ |
|
- | 144 | spinlock_unlock(&t->lock); |
|
- | 145 | goto out; |
|
- | 146 | } |
|
- | 147 | ||
- | 148 | if (!spinlock_trylock(&wq->lock)) { |
|
- | 149 | spinlock_unlock(&t->lock); |
|
- | 150 | goto grab_locks; /* avoid deadlock */ |
|
- | 151 | } |
|
- | 152 | ||
- | 153 | if (t->timeout_pending && timeout_unregister(&t->sleep_timeout)) |
|
- | 154 | t->timeout_pending = false; |
|
- | 155 | ||
- | 156 | list_remove(&t->wq_link); |
|
- | 157 | t->saved_context = t->sleep_interruption_context; |
|
- | 158 | do_wakeup = true; |
|
- | 159 | t->sleep_queue = NULL; |
|
- | 160 | spinlock_unlock(&wq->lock); |
|
- | 161 | } |
|
- | 162 | spinlock_unlock(&t->lock); |
|
- | 163 | ||
- | 164 | if (do_wakeup) |
|
- | 165 | thread_ready(t); |
|
- | 166 | ||
- | 167 | out: |
|
- | 168 | spinlock_unlock(&threads_lock); |
|
- | 169 | interrupts_restore(ipl); |
|
- | 170 | } |
|
119 | 171 | ||
120 | /** Sleep until either wakeup, timeout or interruption occurs |
172 | /** Sleep until either wakeup, timeout or interruption occurs |
121 | * |
173 | * |
122 | * This is a sleep implementation which allows itself to time out or to be |
174 | * This is a sleep implementation which allows itself to time out or to be |
123 | * interrupted from the sleep, restoring a failover context. |
175 | * interrupted from the sleep, restoring a failover context. |
124 | * |
176 | * |
125 | * Sleepers are organised in a FIFO fashion in a structure called wait queue. |
177 | * Sleepers are organised in a FIFO fashion in a structure called wait queue. |
126 | * |
178 | * |
127 | * This function is really basic in that other functions as waitq_sleep() |
179 | * This function is really basic in that other functions as waitq_sleep() |
128 | * and all the *_timeout() functions use it. |
180 | * and all the *_timeout() functions use it. |
129 | * |
181 | * |
130 | * @param wq Pointer to wait queue. |
182 | * @param wq Pointer to wait queue. |
131 | * @param usec Timeout in microseconds. |
183 | * @param usec Timeout in microseconds. |
132 | * @param flags Specify mode of the sleep. |
184 | * @param flags Specify mode of the sleep. |
133 | * |
185 | * |
134 | * The sleep can be interrupted only if the |
186 | * The sleep can be interrupted only if the |
135 | * SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags. |
187 | * SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags. |
136 | * |
188 | * |
137 | * If usec is greater than zero, regardless of the value of the |
189 | * If usec is greater than zero, regardless of the value of the |
138 | * SYNCH_FLAGS_NON_BLOCKING bit in flags, the call will not return until either |
190 | * SYNCH_FLAGS_NON_BLOCKING bit in flags, the call will not return until either |
139 | * timeout, interruption or wakeup comes. |
191 | * timeout, interruption or wakeup comes. |
140 | * |
192 | * |
141 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is not set in flags, |
193 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is not set in flags, |
142 | * the call will not return until wakeup or interruption comes. |
194 | * the call will not return until wakeup or interruption comes. |
143 | * |
195 | * |
144 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the |
196 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the |
145 | * call will immediately return, reporting either success or failure. |
197 | * call will immediately return, reporting either success or failure. |
146 | * |
198 | * |
147 | * @return One of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT, ESYNCH_INTERRUPTED, |
199 | * @return One of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT, ESYNCH_INTERRUPTED, |
148 | * ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED. |
200 | * ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED. |
149 | * |
201 | * |
150 | * @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time of the |
202 | * @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time of the |
151 | * call there was no pending wakeup. |
203 | * call there was no pending wakeup. |
152 | * |
204 | * |
153 | * @li ESYNCH_TIMEOUT means that the sleep timed out. |
205 | * @li ESYNCH_TIMEOUT means that the sleep timed out. |
154 | * |
206 | * |
155 | * @li ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread. |
207 | * @li ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread. |
156 | * |
208 | * |
157 | * @li ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was |
209 | * @li ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was |
158 | * a pending wakeup at the time of the call. The caller was not put |
210 | * a pending wakeup at the time of the call. The caller was not put |
159 | * asleep at all. |
211 | * asleep at all. |
160 | * |
212 | * |
161 | * @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was |
213 | * @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was |
162 | * attempted. |
214 | * attempted. |
163 | */ |
215 | */ |
164 | int waitq_sleep_timeout(waitq_t *wq, uint32_t usec, int flags) |
216 | int waitq_sleep_timeout(waitq_t *wq, uint32_t usec, int flags) |
165 | { |
217 | { |
166 | ipl_t ipl; |
218 | ipl_t ipl; |
167 | int rc; |
219 | int rc; |
168 | 220 | ||
169 | ipl = waitq_sleep_prepare(wq); |
221 | ipl = waitq_sleep_prepare(wq); |
170 | rc = waitq_sleep_timeout_unsafe(wq, usec, flags); |
222 | rc = waitq_sleep_timeout_unsafe(wq, usec, flags); |
171 | waitq_sleep_finish(wq, rc, ipl); |
223 | waitq_sleep_finish(wq, rc, ipl); |
172 | return rc; |
224 | return rc; |
173 | } |
225 | } |
174 | 226 | ||
175 | /** Prepare to sleep in a waitq. |
227 | /** Prepare to sleep in a waitq. |
176 | * |
228 | * |
177 | * This function will return holding the lock of the wait queue |
229 | * This function will return holding the lock of the wait queue |
178 | * and interrupts disabled. |
230 | * and interrupts disabled. |
179 | * |
231 | * |
180 | * @param wq Wait queue. |
232 | * @param wq Wait queue. |
181 | * |
233 | * |
182 | * @return Interrupt level as it existed on entry to this function. |
234 | * @return Interrupt level as it existed on entry to this function. |
183 | */ |
235 | */ |
184 | ipl_t waitq_sleep_prepare(waitq_t *wq) |
236 | ipl_t waitq_sleep_prepare(waitq_t *wq) |
185 | { |
237 | { |
186 | ipl_t ipl; |
238 | ipl_t ipl; |
187 | 239 | ||
188 | restart: |
240 | restart: |
189 | ipl = interrupts_disable(); |
241 | ipl = interrupts_disable(); |
190 | 242 | ||
191 | if (THREAD) { /* needed during system initiailzation */ |
243 | if (THREAD) { /* needed during system initiailzation */ |
192 | /* |
244 | /* |
193 | * Busy waiting for a delayed timeout. |
245 | * Busy waiting for a delayed timeout. |
194 | * This is an important fix for the race condition between |
246 | * This is an important fix for the race condition between |
195 | * a delayed timeout and a next call to waitq_sleep_timeout(). |
247 | * a delayed timeout and a next call to waitq_sleep_timeout(). |
196 | * Simply, the thread is not allowed to go to sleep if |
248 | * Simply, the thread is not allowed to go to sleep if |
197 | * there are timeouts in progress. |
249 | * there are timeouts in progress. |
198 | */ |
250 | */ |
199 | spinlock_lock(&THREAD->lock); |
251 | spinlock_lock(&THREAD->lock); |
200 | if (THREAD->timeout_pending) { |
252 | if (THREAD->timeout_pending) { |
201 | spinlock_unlock(&THREAD->lock); |
253 | spinlock_unlock(&THREAD->lock); |
202 | interrupts_restore(ipl); |
254 | interrupts_restore(ipl); |
203 | goto restart; |
255 | goto restart; |
204 | } |
256 | } |
205 | spinlock_unlock(&THREAD->lock); |
257 | spinlock_unlock(&THREAD->lock); |
206 | } |
258 | } |
207 | 259 | ||
208 | spinlock_lock(&wq->lock); |
260 | spinlock_lock(&wq->lock); |
209 | return ipl; |
261 | return ipl; |
210 | } |
262 | } |
211 | 263 | ||
212 | /** Finish waiting in a wait queue. |
264 | /** Finish waiting in a wait queue. |
213 | * |
265 | * |
214 | * This function restores interrupts to the state that existed prior |
266 | * This function restores interrupts to the state that existed prior |
215 | * to the call to waitq_sleep_prepare(). If necessary, the wait queue |
267 | * to the call to waitq_sleep_prepare(). If necessary, the wait queue |
216 | * lock is released. |
268 | * lock is released. |
217 | * |
269 | * |
218 | * @param wq Wait queue. |
270 | * @param wq Wait queue. |
219 | * @param rc Return code of waitq_sleep_timeout_unsafe(). |
271 | * @param rc Return code of waitq_sleep_timeout_unsafe(). |
220 | * @param ipl Interrupt level returned by waitq_sleep_prepare(). |
272 | * @param ipl Interrupt level returned by waitq_sleep_prepare(). |
221 | */ |
273 | */ |
222 | void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl) |
274 | void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl) |
223 | { |
275 | { |
224 | switch (rc) { |
276 | switch (rc) { |
225 | case ESYNCH_WOULD_BLOCK: |
277 | case ESYNCH_WOULD_BLOCK: |
226 | case ESYNCH_OK_ATOMIC: |
278 | case ESYNCH_OK_ATOMIC: |
227 | spinlock_unlock(&wq->lock); |
279 | spinlock_unlock(&wq->lock); |
228 | break; |
280 | break; |
229 | default: |
281 | default: |
230 | break; |
282 | break; |
231 | } |
283 | } |
232 | interrupts_restore(ipl); |
284 | interrupts_restore(ipl); |
233 | } |
285 | } |
234 | 286 | ||
235 | /** Internal implementation of waitq_sleep_timeout(). |
287 | /** Internal implementation of waitq_sleep_timeout(). |
236 | * |
288 | * |
237 | * This function implements logic of sleeping in a wait queue. |
289 | * This function implements logic of sleeping in a wait queue. |
238 | * This call must be preceeded by a call to waitq_sleep_prepare() |
290 | * This call must be preceeded by a call to waitq_sleep_prepare() |
239 | * and followed by a call to waitq_slee_finish(). |
291 | * and followed by a call to waitq_slee_finish(). |
240 | * |
292 | * |
241 | * @param wq See waitq_sleep_timeout(). |
293 | * @param wq See waitq_sleep_timeout(). |
242 | * @param usec See waitq_sleep_timeout(). |
294 | * @param usec See waitq_sleep_timeout(). |
243 | * @param flags See waitq_sleep_timeout(). |
295 | * @param flags See waitq_sleep_timeout(). |
244 | * |
296 | * |
245 | * @return See waitq_sleep_timeout(). |
297 | * @return See waitq_sleep_timeout(). |
246 | */ |
298 | */ |
247 | int waitq_sleep_timeout_unsafe(waitq_t *wq, uint32_t usec, int flags) |
299 | int waitq_sleep_timeout_unsafe(waitq_t *wq, uint32_t usec, int flags) |
248 | { |
300 | { |
249 | /* checks whether to go to sleep at all */ |
301 | /* checks whether to go to sleep at all */ |
250 | if (wq->missed_wakeups) { |
302 | if (wq->missed_wakeups) { |
251 | wq->missed_wakeups--; |
303 | wq->missed_wakeups--; |
252 | return ESYNCH_OK_ATOMIC; |
304 | return ESYNCH_OK_ATOMIC; |
253 | } |
305 | } |
254 | else { |
306 | else { |
255 | if ((flags & SYNCH_FLAGS_NON_BLOCKING) && (usec == 0)) { |
307 | if ((flags & SYNCH_FLAGS_NON_BLOCKING) && (usec == 0)) { |
256 | /* return immediatelly instead of going to sleep */ |
308 | /* return immediatelly instead of going to sleep */ |
257 | return ESYNCH_WOULD_BLOCK; |
309 | return ESYNCH_WOULD_BLOCK; |
258 | } |
310 | } |
259 | } |
311 | } |
260 | 312 | ||
261 | /* |
313 | /* |
262 | * Now we are firmly decided to go to sleep. |
314 | * Now we are firmly decided to go to sleep. |
263 | */ |
315 | */ |
264 | spinlock_lock(&THREAD->lock); |
316 | spinlock_lock(&THREAD->lock); |
265 | 317 | ||
266 | if (flags & SYNCH_FLAGS_INTERRUPTIBLE) { |
318 | if (flags & SYNCH_FLAGS_INTERRUPTIBLE) { |
267 | 319 | ||
268 | /* |
320 | /* |
269 | * If the thread was already interrupted, |
321 | * If the thread was already interrupted, |
270 | * don't go to sleep at all. |
322 | * don't go to sleep at all. |
271 | */ |
323 | */ |
272 | if (THREAD->interrupted) { |
324 | if (THREAD->interrupted) { |
273 | spinlock_unlock(&THREAD->lock); |
325 | spinlock_unlock(&THREAD->lock); |
274 | spinlock_unlock(&wq->lock); |
326 | spinlock_unlock(&wq->lock); |
275 | return ESYNCH_INTERRUPTED; |
327 | return ESYNCH_INTERRUPTED; |
276 | } |
328 | } |
277 | 329 | ||
278 | /* |
330 | /* |
279 | * Set context that will be restored if the sleep |
331 | * Set context that will be restored if the sleep |
280 | * of this thread is ever interrupted. |
332 | * of this thread is ever interrupted. |
281 | */ |
333 | */ |
282 | THREAD->sleep_interruptible = true; |
334 | THREAD->sleep_interruptible = true; |
283 | if (!context_save(&THREAD->sleep_interruption_context)) { |
335 | if (!context_save(&THREAD->sleep_interruption_context)) { |
284 | /* Short emulation of scheduler() return code. */ |
336 | /* Short emulation of scheduler() return code. */ |
285 | spinlock_unlock(&THREAD->lock); |
337 | spinlock_unlock(&THREAD->lock); |
286 | return ESYNCH_INTERRUPTED; |
338 | return ESYNCH_INTERRUPTED; |
287 | } |
339 | } |
288 | 340 | ||
289 | } else { |
341 | } else { |
290 | THREAD->sleep_interruptible = false; |
342 | THREAD->sleep_interruptible = false; |
291 | } |
343 | } |
292 | 344 | ||
293 | if (usec) { |
345 | if (usec) { |
294 | /* We use the timeout variant. */ |
346 | /* We use the timeout variant. */ |
295 | if (!context_save(&THREAD->sleep_timeout_context)) { |
347 | if (!context_save(&THREAD->sleep_timeout_context)) { |
296 | /* Short emulation of scheduler() return code. */ |
348 | /* Short emulation of scheduler() return code. */ |
297 | spinlock_unlock(&THREAD->lock); |
349 | spinlock_unlock(&THREAD->lock); |
298 | return ESYNCH_TIMEOUT; |
350 | return ESYNCH_TIMEOUT; |
299 | } |
351 | } |
300 | THREAD->timeout_pending = true; |
352 | THREAD->timeout_pending = true; |
301 | timeout_register(&THREAD->sleep_timeout, (uint64_t) usec, |
353 | timeout_register(&THREAD->sleep_timeout, (uint64_t) usec, |
302 | waitq_timeouted_sleep, THREAD); |
354 | waitq_timeouted_sleep, THREAD); |
303 | } |
355 | } |
304 | 356 | ||
305 | list_append(&THREAD->wq_link, &wq->head); |
357 | list_append(&THREAD->wq_link, &wq->head); |
306 | 358 | ||
307 | /* |
359 | /* |
308 | * Suspend execution. |
360 | * Suspend execution. |
309 | */ |
361 | */ |
310 | THREAD->state = Sleeping; |
362 | THREAD->state = Sleeping; |
311 | THREAD->sleep_queue = wq; |
363 | THREAD->sleep_queue = wq; |
312 | 364 | ||
313 | spinlock_unlock(&THREAD->lock); |
365 | spinlock_unlock(&THREAD->lock); |
314 | 366 | ||
315 | /* wq->lock is released in scheduler_separated_stack() */ |
367 | /* wq->lock is released in scheduler_separated_stack() */ |
316 | scheduler(); |
368 | scheduler(); |
317 | 369 | ||
318 | return ESYNCH_OK_BLOCKED; |
370 | return ESYNCH_OK_BLOCKED; |
319 | } |
371 | } |
320 | 372 | ||
321 | 373 | ||
322 | /** Wake up first thread sleeping in a wait queue |
374 | /** Wake up first thread sleeping in a wait queue |
323 | * |
375 | * |
324 | * Wake up first thread sleeping in a wait queue. This is the SMP- and IRQ-safe |
376 | * Wake up first thread sleeping in a wait queue. This is the SMP- and IRQ-safe |
325 | * wrapper meant for general use. |
377 | * wrapper meant for general use. |
326 | * |
378 | * |
327 | * Besides its 'normal' wakeup operation, it attempts to unregister possible |
379 | * Besides its 'normal' wakeup operation, it attempts to unregister possible |
328 | * timeout. |
380 | * timeout. |
329 | * |
381 | * |
330 | * @param wq Pointer to wait queue. |
382 | * @param wq Pointer to wait queue. |
331 | * @param all If this is non-zero, all sleeping threads will be woken up and |
383 | * @param all If this is non-zero, all sleeping threads will be woken up and |
332 | * missed count will be zeroed. |
384 | * missed count will be zeroed. |
333 | */ |
385 | */ |
334 | void waitq_wakeup(waitq_t *wq, bool all) |
386 | void waitq_wakeup(waitq_t *wq, bool all) |
335 | { |
387 | { |
336 | ipl_t ipl; |
388 | ipl_t ipl; |
337 | 389 | ||
338 | ipl = interrupts_disable(); |
390 | ipl = interrupts_disable(); |
339 | spinlock_lock(&wq->lock); |
391 | spinlock_lock(&wq->lock); |
340 | 392 | ||
341 | _waitq_wakeup_unsafe(wq, all); |
393 | _waitq_wakeup_unsafe(wq, all); |
342 | 394 | ||
343 | spinlock_unlock(&wq->lock); |
395 | spinlock_unlock(&wq->lock); |
344 | interrupts_restore(ipl); |
396 | interrupts_restore(ipl); |
345 | } |
397 | } |
346 | 398 | ||
347 | /** Internal SMP- and IRQ-unsafe version of waitq_wakeup() |
399 | /** Internal SMP- and IRQ-unsafe version of waitq_wakeup() |
348 | * |
400 | * |
349 | * This is the internal SMP- and IRQ-unsafe version of waitq_wakeup(). It |
401 | * This is the internal SMP- and IRQ-unsafe version of waitq_wakeup(). It |
350 | * assumes wq->lock is already locked and interrupts are already disabled. |
402 | * assumes wq->lock is already locked and interrupts are already disabled. |
351 | * |
403 | * |
352 | * @param wq Pointer to wait queue. |
404 | * @param wq Pointer to wait queue. |
353 | * @param all If this is non-zero, all sleeping threads will be woken up and |
405 | * @param all If this is non-zero, all sleeping threads will be woken up and |
354 | * missed count will be zeroed. |
406 | * missed count will be zeroed. |
355 | */ |
407 | */ |
356 | void _waitq_wakeup_unsafe(waitq_t *wq, bool all) |
408 | void _waitq_wakeup_unsafe(waitq_t *wq, bool all) |
357 | { |
409 | { |
358 | thread_t *t; |
410 | thread_t *t; |
359 | 411 | ||
360 | loop: |
412 | loop: |
361 | if (list_empty(&wq->head)) { |
413 | if (list_empty(&wq->head)) { |
362 | wq->missed_wakeups++; |
414 | wq->missed_wakeups++; |
363 | if (all) |
415 | if (all) |
364 | wq->missed_wakeups = 0; |
416 | wq->missed_wakeups = 0; |
365 | return; |
417 | return; |
366 | } |
418 | } |
367 | 419 | ||
368 | t = list_get_instance(wq->head.next, thread_t, wq_link); |
420 | t = list_get_instance(wq->head.next, thread_t, wq_link); |
369 | 421 | ||
370 | /* |
422 | /* |
371 | * Lock the thread prior to removing it from the wq. |
423 | * Lock the thread prior to removing it from the wq. |
372 | * This is not necessary because of mutual exclusion |
424 | * This is not necessary because of mutual exclusion |
373 | * (the link belongs to the wait queue), but because |
425 | * (the link belongs to the wait queue), but because |
374 | * of synchronization with waitq_timeouted_sleep() |
426 | * of synchronization with waitq_timeouted_sleep() |
375 | * and thread_interrupt_sleep(). |
427 | * and thread_interrupt_sleep(). |
376 | * |
428 | * |
377 | * In order for these two functions to work, the following |
429 | * In order for these two functions to work, the following |
378 | * invariant must hold: |
430 | * invariant must hold: |
379 | * |
431 | * |
380 | * t->sleep_queue != NULL <=> t sleeps in a wait queue |
432 | * t->sleep_queue != NULL <=> t sleeps in a wait queue |
381 | * |
433 | * |
382 | * For an observer who locks the thread, the invariant |
434 | * For an observer who locks the thread, the invariant |
383 | * holds only when the lock is held prior to removing |
435 | * holds only when the lock is held prior to removing |
384 | * it from the wait queue. |
436 | * it from the wait queue. |
385 | */ |
437 | */ |
386 | spinlock_lock(&t->lock); |
438 | spinlock_lock(&t->lock); |
387 | list_remove(&t->wq_link); |
439 | list_remove(&t->wq_link); |
388 | 440 | ||
389 | if (t->timeout_pending && timeout_unregister(&t->sleep_timeout)) |
441 | if (t->timeout_pending && timeout_unregister(&t->sleep_timeout)) |
390 | t->timeout_pending = false; |
442 | t->timeout_pending = false; |
391 | t->sleep_queue = NULL; |
443 | t->sleep_queue = NULL; |
392 | spinlock_unlock(&t->lock); |
444 | spinlock_unlock(&t->lock); |
393 | 445 | ||
394 | thread_ready(t); |
446 | thread_ready(t); |
395 | 447 | ||
396 | if (all) |
448 | if (all) |
397 | goto loop; |
449 | goto loop; |
398 | } |
450 | } |
399 | 451 | ||
400 | /** @} |
452 | /** @} |
401 | */ |
453 | */ |
402 | 454 |