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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 | /** |
29 | /** |
30 | * @file waitq.c |
30 | * @file waitq.c |
31 | * @brief Wait queue. |
31 | * @brief Wait queue. |
32 | * |
32 | * |
33 | * Wait queue is the basic synchronization primitive upon which all |
33 | * Wait queue is the basic synchronization primitive upon which all |
34 | * other synchronization primitives build. |
34 | * other synchronization primitives build. |
35 | * |
35 | * |
36 | * It allows threads to wait for an event in first-come, first-served |
36 | * It allows threads to wait for an event in first-come, first-served |
37 | * fashion. Conditional operation as well as timeouts and interruptions |
37 | * fashion. Conditional operation as well as timeouts and interruptions |
38 | * are supported. |
38 | * are supported. |
39 | */ |
39 | */ |
40 | 40 | ||
41 | #include <synch/waitq.h> |
41 | #include <synch/waitq.h> |
42 | #include <synch/synch.h> |
42 | #include <synch/synch.h> |
43 | #include <synch/spinlock.h> |
43 | #include <synch/spinlock.h> |
44 | #include <proc/thread.h> |
44 | #include <proc/thread.h> |
45 | #include <proc/scheduler.h> |
45 | #include <proc/scheduler.h> |
46 | #include <arch/asm.h> |
46 | #include <arch/asm.h> |
47 | #include <arch/types.h> |
47 | #include <arch/types.h> |
48 | #include <typedefs.h> |
48 | #include <typedefs.h> |
49 | #include <time/timeout.h> |
49 | #include <time/timeout.h> |
50 | #include <arch.h> |
50 | #include <arch.h> |
51 | #include <context.h> |
51 | #include <context.h> |
52 | #include <adt/list.h> |
52 | #include <adt/list.h> |
53 | 53 | ||
54 | static void waitq_timeouted_sleep(void *data); |
54 | static void waitq_timeouted_sleep(void *data); |
55 | 55 | ||
56 | /** Initialize wait queue |
56 | /** Initialize wait queue |
57 | * |
57 | * |
58 | * Initialize wait queue. |
58 | * Initialize wait queue. |
59 | * |
59 | * |
60 | * @param wq Pointer to wait queue to be initialized. |
60 | * @param wq Pointer to wait queue to be initialized. |
61 | */ |
61 | */ |
62 | void waitq_initialize(waitq_t *wq) |
62 | void waitq_initialize(waitq_t *wq) |
63 | { |
63 | { |
64 | spinlock_initialize(&wq->lock, "waitq_lock"); |
64 | spinlock_initialize(&wq->lock, "waitq_lock"); |
65 | list_initialize(&wq->head); |
65 | list_initialize(&wq->head); |
66 | wq->missed_wakeups = 0; |
66 | wq->missed_wakeups = 0; |
67 | } |
67 | } |
68 | 68 | ||
69 | /** Handle timeout during waitq_sleep_timeout() call |
69 | /** Handle timeout during waitq_sleep_timeout() call |
70 | * |
70 | * |
71 | * This routine is called when waitq_sleep_timeout() timeouts. |
71 | * This routine is called when waitq_sleep_timeout() timeouts. |
72 | * Interrupts are disabled. |
72 | * Interrupts are disabled. |
73 | * |
73 | * |
74 | * It is supposed to try to remove 'its' thread from the wait queue; |
74 | * It is supposed to try to remove 'its' thread from the wait queue; |
75 | * it can eventually fail to achieve this goal when these two events |
75 | * it can eventually fail to achieve this goal when these two events |
76 | * overlap. In that case it behaves just as though there was no |
76 | * overlap. In that case it behaves just as though there was no |
77 | * timeout at all. |
77 | * timeout at all. |
78 | * |
78 | * |
79 | * @param data Pointer to the thread that called waitq_sleep_timeout(). |
79 | * @param data Pointer to the thread that called waitq_sleep_timeout(). |
80 | */ |
80 | */ |
81 | void waitq_timeouted_sleep(void *data) |
81 | void waitq_timeouted_sleep(void *data) |
82 | { |
82 | { |
83 | thread_t *t = (thread_t *) data; |
83 | thread_t *t = (thread_t *) data; |
84 | waitq_t *wq; |
84 | waitq_t *wq; |
85 | bool do_wakeup = false; |
85 | bool do_wakeup = false; |
86 | 86 | ||
87 | spinlock_lock(&threads_lock); |
87 | spinlock_lock(&threads_lock); |
88 | if (!thread_exists(t)) |
88 | if (!thread_exists(t)) |
89 | goto out; |
89 | goto out; |
90 | 90 | ||
91 | grab_locks: |
91 | grab_locks: |
92 | spinlock_lock(&t->lock); |
92 | spinlock_lock(&t->lock); |
93 | if ((wq = t->sleep_queue)) { /* assignment */ |
93 | if ((wq = t->sleep_queue)) { /* assignment */ |
94 | if (!spinlock_trylock(&wq->lock)) { |
94 | if (!spinlock_trylock(&wq->lock)) { |
95 | spinlock_unlock(&t->lock); |
95 | spinlock_unlock(&t->lock); |
96 | goto grab_locks; /* avoid deadlock */ |
96 | goto grab_locks; /* avoid deadlock */ |
97 | } |
97 | } |
98 | 98 | ||
99 | list_remove(&t->wq_link); |
99 | list_remove(&t->wq_link); |
100 | t->saved_context = t->sleep_timeout_context; |
100 | t->saved_context = t->sleep_timeout_context; |
101 | do_wakeup = true; |
101 | do_wakeup = true; |
102 | 102 | ||
103 | spinlock_unlock(&wq->lock); |
103 | spinlock_unlock(&wq->lock); |
104 | t->sleep_queue = NULL; |
104 | t->sleep_queue = NULL; |
105 | } |
105 | } |
106 | 106 | ||
107 | t->timeout_pending = false; |
107 | t->timeout_pending = false; |
108 | spinlock_unlock(&t->lock); |
108 | spinlock_unlock(&t->lock); |
109 | 109 | ||
110 | if (do_wakeup) |
110 | if (do_wakeup) |
111 | thread_ready(t); |
111 | thread_ready(t); |
112 | 112 | ||
113 | out: |
113 | out: |
114 | spinlock_unlock(&threads_lock); |
114 | spinlock_unlock(&threads_lock); |
115 | } |
115 | } |
116 | 116 | ||
117 | /** Interrupt sleeping thread. |
117 | /** Interrupt sleeping thread. |
118 | * |
118 | * |
119 | * This routine attempts to interrupt a thread from its sleep in a waitqueue. |
119 | * This routine attempts to interrupt a thread from its sleep in a waitqueue. |
120 | * If the thread is not found sleeping, no action is taken. |
120 | * If the thread is not found sleeping, no action is taken. |
121 | * |
121 | * |
122 | * @param t Thread to be interrupted. |
122 | * @param t Thread to be interrupted. |
123 | */ |
123 | */ |
124 | void waitq_interrupt_sleep(thread_t *t) |
124 | void waitq_interrupt_sleep(thread_t *t) |
125 | { |
125 | { |
126 | waitq_t *wq; |
126 | waitq_t *wq; |
127 | bool do_wakeup = false; |
127 | bool do_wakeup = false; |
128 | ipl_t ipl; |
128 | ipl_t ipl; |
129 | 129 | ||
130 | ipl = interrupts_disable(); |
130 | ipl = interrupts_disable(); |
131 | spinlock_lock(&threads_lock); |
131 | spinlock_lock(&threads_lock); |
132 | if (!thread_exists(t)) |
132 | if (!thread_exists(t)) |
133 | goto out; |
133 | goto out; |
134 | 134 | ||
135 | grab_locks: |
135 | grab_locks: |
136 | spinlock_lock(&t->lock); |
136 | spinlock_lock(&t->lock); |
137 | if ((wq = t->sleep_queue)) { /* assignment */ |
137 | if ((wq = t->sleep_queue)) { /* assignment */ |
138 | if (!(t->sleep_interruptible)) { |
138 | if (!(t->sleep_interruptible)) { |
139 | /* |
139 | /* |
140 | * The sleep cannot be interrupted. |
140 | * The sleep cannot be interrupted. |
141 | */ |
141 | */ |
142 | spinlock_unlock(&t->lock); |
142 | spinlock_unlock(&t->lock); |
143 | goto out; |
143 | goto out; |
144 | } |
144 | } |
145 | 145 | ||
146 | if (!spinlock_trylock(&wq->lock)) { |
146 | if (!spinlock_trylock(&wq->lock)) { |
147 | spinlock_unlock(&t->lock); |
147 | spinlock_unlock(&t->lock); |
148 | goto grab_locks; /* avoid deadlock */ |
148 | goto grab_locks; /* avoid deadlock */ |
149 | } |
149 | } |
150 | 150 | ||
151 | list_remove(&t->wq_link); |
151 | list_remove(&t->wq_link); |
152 | t->saved_context = t->sleep_interruption_context; |
152 | t->saved_context = t->sleep_interruption_context; |
153 | do_wakeup = true; |
153 | do_wakeup = true; |
154 | 154 | ||
155 | spinlock_unlock(&wq->lock); |
155 | spinlock_unlock(&wq->lock); |
156 | t->sleep_queue = NULL; |
156 | t->sleep_queue = NULL; |
157 | } |
157 | } |
158 | spinlock_unlock(&t->lock); |
158 | spinlock_unlock(&t->lock); |
159 | 159 | ||
160 | if (do_wakeup) |
160 | if (do_wakeup) |
161 | thread_ready(t); |
161 | thread_ready(t); |
162 | 162 | ||
163 | out: |
163 | out: |
164 | spinlock_unlock(&threads_lock); |
164 | spinlock_unlock(&threads_lock); |
165 | interrupts_restore(ipl); |
165 | interrupts_restore(ipl); |
166 | } |
166 | } |
167 | 167 | ||
168 | /** Sleep until either wakeup, timeout or interruption occurs |
168 | /** Sleep until either wakeup, timeout or interruption occurs |
169 | * |
169 | * |
170 | * This is a sleep implementation which allows itself to time out or to be |
170 | * This is a sleep implementation which allows itself to time out or to be |
171 | * interrupted from the sleep, restoring a failover context. |
171 | * interrupted from the sleep, restoring a failover context. |
172 | * |
172 | * |
173 | * Sleepers are organised in a FIFO fashion in a structure called wait queue. |
173 | * Sleepers are organised in a FIFO fashion in a structure called wait queue. |
174 | * |
174 | * |
175 | * This function is really basic in that other functions as waitq_sleep() |
175 | * This function is really basic in that other functions as waitq_sleep() |
176 | * and all the *_timeout() functions use it. |
176 | * and all the *_timeout() functions use it. |
177 | * |
177 | * |
178 | * @param wq Pointer to wait queue. |
178 | * @param wq Pointer to wait queue. |
179 | * @param usec Timeout in microseconds. |
179 | * @param usec Timeout in microseconds. |
180 | * @param flags Specify mode of the sleep. |
180 | * @param flags Specify mode of the sleep. |
181 | * |
181 | * |
182 | * The sleep can be interrupted only if the |
182 | * The sleep can be interrupted only if the |
183 | * SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags. |
183 | * SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags. |
184 | |
184 | |
185 | * If usec is greater than zero, regardless of the value of the |
185 | * If usec is greater than zero, regardless of the value of the |
186 | * SYNCH_FLAGS_NON_BLOCKING bit in flags, the call will not return until either timeout, |
186 | * SYNCH_FLAGS_NON_BLOCKING bit in flags, the call will not return until either timeout, |
187 | * interruption or wakeup comes. |
187 | * interruption or wakeup comes. |
188 | * |
188 | * |
189 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is not set in flags, the call |
189 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is not set in flags, the call |
190 | * will not return until wakeup or interruption comes. |
190 | * will not return until wakeup or interruption comes. |
191 | * |
191 | * |
192 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the call will |
192 | * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the call will |
193 | * immediately return, reporting either success or failure. |
193 | * immediately return, reporting either success or failure. |
194 | * |
194 | * |
195 | * @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT, ESYNCH_INTERRUPTED, |
195 | * @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT, ESYNCH_INTERRUPTED, |
196 | * ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED. |
196 | * ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED. |
197 | * |
197 | * |
198 | * @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time |
198 | * @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time |
199 | * of the call there was no pending wakeup. |
199 | * of the call there was no pending wakeup. |
200 | * |
200 | * |
201 | * @li ESYNCH_TIMEOUT means that the sleep timed out. |
201 | * @li ESYNCH_TIMEOUT means that the sleep timed out. |
202 | * |
202 | * |
203 | * @li ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread. |
203 | * @li ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread. |
204 | * |
204 | * |
205 | * @li ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was |
205 | * @li ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was |
206 | * a pending wakeup at the time of the call. The caller was not put |
206 | * a pending wakeup at the time of the call. The caller was not put |
207 | * asleep at all. |
207 | * asleep at all. |
208 | * |
208 | * |
209 | * @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was |
209 | * @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was |
210 | * attempted. |
210 | * attempted. |
211 | */ |
211 | */ |
212 | int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int flags) |
212 | int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int flags) |
213 | { |
213 | { |
214 | ipl_t ipl; |
214 | ipl_t ipl; |
215 | int rc; |
215 | int rc; |
216 | 216 | ||
217 | ipl = waitq_sleep_prepare(wq); |
217 | ipl = waitq_sleep_prepare(wq); |
218 | rc = waitq_sleep_timeout_unsafe(wq, usec, flags); |
218 | rc = waitq_sleep_timeout_unsafe(wq, usec, flags); |
219 | waitq_sleep_finish(wq, rc, ipl); |
219 | waitq_sleep_finish(wq, rc, ipl); |
220 | return rc; |
220 | return rc; |
221 | } |
221 | } |
222 | 222 | ||
223 | /** Prepare to sleep in a waitq. |
223 | /** Prepare to sleep in a waitq. |
224 | * |
224 | * |
225 | * This function will return holding the lock of the wait queue |
225 | * This function will return holding the lock of the wait queue |
226 | * and interrupts disabled. |
226 | * and interrupts disabled. |
227 | * |
227 | * |
228 | * @param wq Wait queue. |
228 | * @param wq Wait queue. |
229 | * |
229 | * |
230 | * @return Interrupt level as it existed on entry to this function. |
230 | * @return Interrupt level as it existed on entry to this function. |
231 | */ |
231 | */ |
232 | ipl_t waitq_sleep_prepare(waitq_t *wq) |
232 | ipl_t waitq_sleep_prepare(waitq_t *wq) |
233 | { |
233 | { |
234 | ipl_t ipl; |
234 | ipl_t ipl; |
235 | 235 | ||
236 | restart: |
236 | restart: |
237 | ipl = interrupts_disable(); |
237 | ipl = interrupts_disable(); |
238 | 238 | ||
239 | if (THREAD) { /* needed during system initiailzation */ |
239 | if (THREAD) { /* needed during system initiailzation */ |
240 | /* |
240 | /* |
241 | * Busy waiting for a delayed timeout. |
241 | * Busy waiting for a delayed timeout. |
242 | * This is an important fix for the race condition between |
242 | * This is an important fix for the race condition between |
243 | * a delayed timeout and a next call to waitq_sleep_timeout(). |
243 | * a delayed timeout and a next call to waitq_sleep_timeout(). |
244 | * Simply, the thread is not allowed to go to sleep if |
244 | * Simply, the thread is not allowed to go to sleep if |
245 | * there are timeouts in progress. |
245 | * there are timeouts in progress. |
246 | */ |
246 | */ |
247 | spinlock_lock(&THREAD->lock); |
247 | spinlock_lock(&THREAD->lock); |
248 | if (THREAD->timeout_pending) { |
248 | if (THREAD->timeout_pending) { |
249 | spinlock_unlock(&THREAD->lock); |
249 | spinlock_unlock(&THREAD->lock); |
250 | interrupts_restore(ipl); |
250 | interrupts_restore(ipl); |
251 | goto restart; |
251 | goto restart; |
252 | } |
252 | } |
253 | spinlock_unlock(&THREAD->lock); |
253 | spinlock_unlock(&THREAD->lock); |
254 | } |
254 | } |
255 | 255 | ||
256 | spinlock_lock(&wq->lock); |
256 | spinlock_lock(&wq->lock); |
257 | return ipl; |
257 | return ipl; |
258 | } |
258 | } |
259 | 259 | ||
260 | /** Finish waiting in a wait queue. |
260 | /** Finish waiting in a wait queue. |
261 | * |
261 | * |
262 | * This function restores interrupts to the state that existed prior |
262 | * This function restores interrupts to the state that existed prior |
263 | * to the call to waitq_sleep_prepare(). If necessary, the wait queue |
263 | * to the call to waitq_sleep_prepare(). If necessary, the wait queue |
264 | * lock is released. |
264 | * lock is released. |
265 | * |
265 | * |
266 | * @param wq Wait queue. |
266 | * @param wq Wait queue. |
267 | * @param rc Return code of waitq_sleep_timeout_unsafe(). |
267 | * @param rc Return code of waitq_sleep_timeout_unsafe(). |
268 | * @param ipl Interrupt level returned by waitq_sleep_prepare(). |
268 | * @param ipl Interrupt level returned by waitq_sleep_prepare(). |
269 | */ |
269 | */ |
270 | void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl) |
270 | void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl) |
271 | { |
271 | { |
272 | switch (rc) { |
272 | switch (rc) { |
273 | case ESYNCH_WOULD_BLOCK: |
273 | case ESYNCH_WOULD_BLOCK: |
274 | case ESYNCH_OK_ATOMIC: |
274 | case ESYNCH_OK_ATOMIC: |
275 | spinlock_unlock(&wq->lock); |
275 | spinlock_unlock(&wq->lock); |
276 | break; |
276 | break; |
277 | default: |
277 | default: |
278 | break; |
278 | break; |
279 | } |
279 | } |
280 | interrupts_restore(ipl); |
280 | interrupts_restore(ipl); |
281 | } |
281 | } |
282 | 282 | ||
283 | /** Internal implementation of waitq_sleep_timeout(). |
283 | /** Internal implementation of waitq_sleep_timeout(). |
284 | * |
284 | * |
285 | * This function implements logic of sleeping in a wait queue. |
285 | * This function implements logic of sleeping in a wait queue. |
286 | * This call must be preceeded by a call to waitq_sleep_prepare() |
286 | * This call must be preceeded by a call to waitq_sleep_prepare() |
287 | * and followed by a call to waitq_slee_finish(). |
287 | * and followed by a call to waitq_slee_finish(). |
288 | * |
288 | * |
289 | * @param wq See waitq_sleep_timeout(). |
289 | * @param wq See waitq_sleep_timeout(). |
290 | * @param usec See waitq_sleep_timeout(). |
290 | * @param usec See waitq_sleep_timeout(). |
291 | * @param flags See waitq_sleep_timeout(). |
291 | * @param flags See waitq_sleep_timeout(). |
292 | * |
292 | * |
293 | * @return See waitq_sleep_timeout(). |
293 | * @return See waitq_sleep_timeout(). |
294 | */ |
294 | */ |
295 | int waitq_sleep_timeout_unsafe(waitq_t *wq, __u32 usec, int flags) |
295 | int waitq_sleep_timeout_unsafe(waitq_t *wq, __u32 usec, int flags) |
296 | { |
296 | { |
297 | /* checks whether to go to sleep at all */ |
297 | /* checks whether to go to sleep at all */ |
298 | if (wq->missed_wakeups) { |
298 | if (wq->missed_wakeups) { |
299 | wq->missed_wakeups--; |
299 | wq->missed_wakeups--; |
300 | return ESYNCH_OK_ATOMIC; |
300 | return ESYNCH_OK_ATOMIC; |
301 | } |
301 | } |
302 | else { |
302 | else { |
303 | if ((flags & SYNCH_FLAGS_NON_BLOCKING) && (usec == 0)) { |
303 | if ((flags & SYNCH_FLAGS_NON_BLOCKING) && (usec == 0)) { |
304 | /* return immediatelly instead of going to sleep */ |
304 | /* return immediatelly instead of going to sleep */ |
305 | return ESYNCH_WOULD_BLOCK; |
305 | return ESYNCH_WOULD_BLOCK; |
306 | } |
306 | } |
307 | } |
307 | } |
308 | 308 | ||
309 | /* |
309 | /* |
310 | * Now we are firmly decided to go to sleep. |
310 | * Now we are firmly decided to go to sleep. |
311 | */ |
311 | */ |
312 | spinlock_lock(&THREAD->lock); |
312 | spinlock_lock(&THREAD->lock); |
313 | 313 | ||
314 | if (THREAD->interrupted) { |
- | |
315 | spinlock_unlock(&THREAD->lock); |
- | |
316 | spinlock_unlock(&wq->lock); |
- | |
317 | return ESYNCH_INTERRUPTED; |
- | |
318 | } |
- | |
319 | - | ||
320 | if (flags & SYNCH_FLAGS_INTERRUPTIBLE) { |
314 | if (flags & SYNCH_FLAGS_INTERRUPTIBLE) { |
- | 315 | ||
- | 316 | /* |
|
- | 317 | * If the thread was already interrupted, |
|
- | 318 | * don't go to sleep at all. |
|
- | 319 | */ |
|
- | 320 | if (THREAD->interrupted) { |
|
- | 321 | spinlock_unlock(&THREAD->lock); |
|
- | 322 | spinlock_unlock(&wq->lock); |
|
- | 323 | return ESYNCH_INTERRUPTED; |
|
- | 324 | } |
|
- | 325 | ||
321 | /* |
326 | /* |
322 | * Set context that will be restored if the sleep |
327 | * Set context that will be restored if the sleep |
323 | * of this thread is ever interrupted. |
328 | * of this thread is ever interrupted. |
324 | */ |
329 | */ |
325 | THREAD->sleep_interruptible = true; |
330 | THREAD->sleep_interruptible = true; |
326 | if (!context_save(&THREAD->sleep_interruption_context)) { |
331 | if (!context_save(&THREAD->sleep_interruption_context)) { |
327 | /* Short emulation of scheduler() return code. */ |
332 | /* Short emulation of scheduler() return code. */ |
328 | spinlock_unlock(&THREAD->lock); |
333 | spinlock_unlock(&THREAD->lock); |
329 | return ESYNCH_INTERRUPTED; |
334 | return ESYNCH_INTERRUPTED; |
330 | } |
335 | } |
- | 336 | ||
331 | } else { |
337 | } else { |
332 | THREAD->sleep_interruptible = false; |
338 | THREAD->sleep_interruptible = false; |
333 | } |
339 | } |
334 | 340 | ||
335 | if (usec) { |
341 | if (usec) { |
336 | /* We use the timeout variant. */ |
342 | /* We use the timeout variant. */ |
337 | if (!context_save(&THREAD->sleep_timeout_context)) { |
343 | if (!context_save(&THREAD->sleep_timeout_context)) { |
338 | /* Short emulation of scheduler() return code. */ |
344 | /* Short emulation of scheduler() return code. */ |
339 | spinlock_unlock(&THREAD->lock); |
345 | spinlock_unlock(&THREAD->lock); |
340 | return ESYNCH_TIMEOUT; |
346 | return ESYNCH_TIMEOUT; |
341 | } |
347 | } |
342 | THREAD->timeout_pending = true; |
348 | THREAD->timeout_pending = true; |
343 | timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_timeouted_sleep, THREAD); |
349 | timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_timeouted_sleep, THREAD); |
344 | } |
350 | } |
345 | 351 | ||
346 | list_append(&THREAD->wq_link, &wq->head); |
352 | list_append(&THREAD->wq_link, &wq->head); |
347 | 353 | ||
348 | /* |
354 | /* |
349 | * Suspend execution. |
355 | * Suspend execution. |
350 | */ |
356 | */ |
351 | THREAD->state = Sleeping; |
357 | THREAD->state = Sleeping; |
352 | THREAD->sleep_queue = wq; |
358 | THREAD->sleep_queue = wq; |
353 | 359 | ||
354 | spinlock_unlock(&THREAD->lock); |
360 | spinlock_unlock(&THREAD->lock); |
355 | 361 | ||
356 | scheduler(); /* wq->lock is released in scheduler_separated_stack() */ |
362 | scheduler(); /* wq->lock is released in scheduler_separated_stack() */ |
357 | 363 | ||
358 | return ESYNCH_OK_BLOCKED; |
364 | return ESYNCH_OK_BLOCKED; |
359 | } |
365 | } |
360 | 366 | ||
361 | 367 | ||
362 | /** Wake up first thread sleeping in a wait queue |
368 | /** Wake up first thread sleeping in a wait queue |
363 | * |
369 | * |
364 | * Wake up first thread sleeping in a wait queue. |
370 | * Wake up first thread sleeping in a wait queue. |
365 | * This is the SMP- and IRQ-safe wrapper meant for |
371 | * This is the SMP- and IRQ-safe wrapper meant for |
366 | * general use. |
372 | * general use. |
367 | * |
373 | * |
368 | * Besides its 'normal' wakeup operation, it attempts |
374 | * Besides its 'normal' wakeup operation, it attempts |
369 | * to unregister possible timeout. |
375 | * to unregister possible timeout. |
370 | * |
376 | * |
371 | * @param wq Pointer to wait queue. |
377 | * @param wq Pointer to wait queue. |
372 | * @param all If this is non-zero, all sleeping threads |
378 | * @param all If this is non-zero, all sleeping threads |
373 | * will be woken up and missed count will be zeroed. |
379 | * will be woken up and missed count will be zeroed. |
374 | */ |
380 | */ |
375 | void waitq_wakeup(waitq_t *wq, bool all) |
381 | void waitq_wakeup(waitq_t *wq, bool all) |
376 | { |
382 | { |
377 | ipl_t ipl; |
383 | ipl_t ipl; |
378 | 384 | ||
379 | ipl = interrupts_disable(); |
385 | ipl = interrupts_disable(); |
380 | spinlock_lock(&wq->lock); |
386 | spinlock_lock(&wq->lock); |
381 | 387 | ||
382 | _waitq_wakeup_unsafe(wq, all); |
388 | _waitq_wakeup_unsafe(wq, all); |
383 | 389 | ||
384 | spinlock_unlock(&wq->lock); |
390 | spinlock_unlock(&wq->lock); |
385 | interrupts_restore(ipl); |
391 | interrupts_restore(ipl); |
386 | } |
392 | } |
387 | 393 | ||
388 | /** Internal SMP- and IRQ-unsafe version of waitq_wakeup() |
394 | /** Internal SMP- and IRQ-unsafe version of waitq_wakeup() |
389 | * |
395 | * |
390 | * This is the internal SMP- and IRQ-unsafe version |
396 | * This is the internal SMP- and IRQ-unsafe version |
391 | * of waitq_wakeup(). It assumes wq->lock is already |
397 | * of waitq_wakeup(). It assumes wq->lock is already |
392 | * locked and interrupts are already disabled. |
398 | * locked and interrupts are already disabled. |
393 | * |
399 | * |
394 | * @param wq Pointer to wait queue. |
400 | * @param wq Pointer to wait queue. |
395 | * @param all If this is non-zero, all sleeping threads |
401 | * @param all If this is non-zero, all sleeping threads |
396 | * will be woken up and missed count will be zeroed. |
402 | * will be woken up and missed count will be zeroed. |
397 | */ |
403 | */ |
398 | void _waitq_wakeup_unsafe(waitq_t *wq, bool all) |
404 | void _waitq_wakeup_unsafe(waitq_t *wq, bool all) |
399 | { |
405 | { |
400 | thread_t *t; |
406 | thread_t *t; |
401 | 407 | ||
402 | loop: |
408 | loop: |
403 | if (list_empty(&wq->head)) { |
409 | if (list_empty(&wq->head)) { |
404 | wq->missed_wakeups++; |
410 | wq->missed_wakeups++; |
405 | if (all) |
411 | if (all) |
406 | wq->missed_wakeups = 0; |
412 | wq->missed_wakeups = 0; |
407 | return; |
413 | return; |
408 | } |
414 | } |
409 | 415 | ||
410 | t = list_get_instance(wq->head.next, thread_t, wq_link); |
416 | t = list_get_instance(wq->head.next, thread_t, wq_link); |
411 | 417 | ||
412 | list_remove(&t->wq_link); |
418 | list_remove(&t->wq_link); |
413 | spinlock_lock(&t->lock); |
419 | spinlock_lock(&t->lock); |
414 | if (t->timeout_pending && timeout_unregister(&t->sleep_timeout)) |
420 | if (t->timeout_pending && timeout_unregister(&t->sleep_timeout)) |
415 | t->timeout_pending = false; |
421 | t->timeout_pending = false; |
416 | t->sleep_queue = NULL; |
422 | t->sleep_queue = NULL; |
417 | spinlock_unlock(&t->lock); |
423 | spinlock_unlock(&t->lock); |
418 | 424 | ||
419 | thread_ready(t); |
425 | thread_ready(t); |
420 | 426 | ||
421 | if (all) |
427 | if (all) |
422 | goto loop; |
428 | goto loop; |
423 | } |
429 | } |
424 | 430 |