Commit | Line | Data |
---|---|---|
9f1621ca | 1 | /* |
7ac06cef | 2 | * urcu-qsbr.c |
9f1621ca | 3 | * |
7ac06cef | 4 | * Userspace RCU QSBR library |
9f1621ca | 5 | * |
6982d6d7 | 6 | * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
9f1621ca MD |
7 | * Copyright (c) 2009 Paul E. McKenney, IBM Corporation. |
8 | * | |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | * | |
23 | * IBM's contributions to this file may be relicensed under LGPLv2 or later. | |
24 | */ | |
25 | ||
c1d2c60b | 26 | #define _GNU_SOURCE |
71c811bf | 27 | #define _LGPL_SOURCE |
9f1621ca MD |
28 | #include <stdio.h> |
29 | #include <pthread.h> | |
30 | #include <signal.h> | |
31 | #include <assert.h> | |
32 | #include <stdlib.h> | |
6d841bc2 | 33 | #include <stdint.h> |
9f1621ca MD |
34 | #include <string.h> |
35 | #include <errno.h> | |
36 | #include <poll.h> | |
37 | ||
d73fb81f | 38 | #include "urcu/wfcqueue.h" |
57760d44 | 39 | #include "urcu/map/urcu-qsbr.h" |
727f819d | 40 | #define BUILD_QSBR_LIB |
af7c2dbe | 41 | #include "urcu/static/urcu-qsbr.h" |
618b2595 | 42 | #include "urcu-pointer.h" |
bd252a04 | 43 | #include "urcu/tls-compat.h" |
71c811bf | 44 | |
4a6d7378 | 45 | #include "urcu-die.h" |
cba82d7b | 46 | #include "urcu-wait.h" |
4a6d7378 | 47 | |
9f1621ca | 48 | /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ |
71c811bf | 49 | #undef _LGPL_SOURCE |
7ac06cef | 50 | #include "urcu-qsbr.h" |
71c811bf | 51 | #define _LGPL_SOURCE |
9f1621ca | 52 | |
f6d18c64 MD |
53 | void __attribute__((destructor)) rcu_exit(void); |
54 | ||
3c29ca5d MD |
55 | /* |
56 | * rcu_gp_lock ensures mutual exclusion between threads calling | |
57 | * synchronize_rcu(). | |
58 | */ | |
6abb4bd5 | 59 | static pthread_mutex_t rcu_gp_lock = PTHREAD_MUTEX_INITIALIZER; |
3c29ca5d MD |
60 | /* |
61 | * rcu_registry_lock ensures mutual exclusion between threads | |
62 | * registering and unregistering themselves to/from the registry, and | |
63 | * with threads reading that registry from synchronize_rcu(). However, | |
64 | * this lock is not held all the way through the completion of awaiting | |
65 | * for the grace period. It is sporadically released between iterations | |
66 | * on the registry. | |
67 | * rcu_registry_lock may nest inside rcu_gp_lock. | |
68 | */ | |
69 | static pthread_mutex_t rcu_registry_lock = PTHREAD_MUTEX_INITIALIZER; | |
4de0cd31 | 70 | struct rcu_gp rcu_gp = { .ctr = RCU_GP_ONLINE }; |
9f1621ca | 71 | |
408f6d92 PB |
72 | /* |
73 | * Active attempts to check for reader Q.S. before calling futex(). | |
74 | */ | |
75 | #define RCU_QS_ACTIVE_ATTEMPTS 100 | |
76 | ||
9f1621ca MD |
77 | /* |
78 | * Written to only by each individual reader. Read by both the reader and the | |
79 | * writers. | |
80 | */ | |
1182f6f0 | 81 | __DEFINE_URCU_TLS_GLOBAL(struct rcu_reader, rcu_reader); |
9f1621ca MD |
82 | |
83 | #ifdef DEBUG_YIELD | |
1de4df4b | 84 | unsigned int rcu_yield_active; |
1182f6f0 | 85 | __DEFINE_URCU_TLS_GLOBAL(unsigned int, rcu_rand_yield); |
9f1621ca MD |
86 | #endif |
87 | ||
16aa9ee8 | 88 | static CDS_LIST_HEAD(registry); |
9f1621ca | 89 | |
6362f68f | 90 | /* |
bf6822a6 | 91 | * Queue keeping threads awaiting to wait for a grace period. Contains |
6362f68f MD |
92 | * struct gp_waiters_thread objects. |
93 | */ | |
bf6822a6 | 94 | static DEFINE_URCU_WAIT_QUEUE(gp_waiters); |
6362f68f | 95 | |
6abb4bd5 | 96 | static void mutex_lock(pthread_mutex_t *mutex) |
9f1621ca MD |
97 | { |
98 | int ret; | |
99 | ||
100 | #ifndef DISTRUST_SIGNALS_EXTREME | |
6abb4bd5 | 101 | ret = pthread_mutex_lock(mutex); |
4a6d7378 MD |
102 | if (ret) |
103 | urcu_die(ret); | |
9f1621ca | 104 | #else /* #ifndef DISTRUST_SIGNALS_EXTREME */ |
6abb4bd5 | 105 | while ((ret = pthread_mutex_trylock(mutex)) != 0) { |
4a6d7378 MD |
106 | if (ret != EBUSY && ret != EINTR) |
107 | urcu_die(ret); | |
9f1621ca MD |
108 | poll(NULL,0,10); |
109 | } | |
110 | #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */ | |
111 | } | |
112 | ||
6abb4bd5 | 113 | static void mutex_unlock(pthread_mutex_t *mutex) |
9f1621ca MD |
114 | { |
115 | int ret; | |
116 | ||
6abb4bd5 | 117 | ret = pthread_mutex_unlock(mutex); |
4a6d7378 MD |
118 | if (ret) |
119 | urcu_die(ret); | |
9f1621ca MD |
120 | } |
121 | ||
bc6c15bb MD |
122 | /* |
123 | * synchronize_rcu() waiting. Single thread. | |
124 | */ | |
4d703340 | 125 | static void wait_gp(void) |
bc6c15bb | 126 | { |
4d703340 | 127 | /* Read reader_gp before read futex */ |
5481ddb3 | 128 | cmm_smp_rmb(); |
15302e28 LJ |
129 | if (uatomic_read(&rcu_gp.futex) == -1) |
130 | futex_noasync(&rcu_gp.futex, FUTEX_WAIT, -1, | |
4d703340 | 131 | NULL, NULL, 0); |
bc6c15bb MD |
132 | } |
133 | ||
3c29ca5d MD |
134 | /* |
135 | * Always called with rcu_registry lock held. Releases this lock between | |
136 | * iterations and grabs it again. Holds the lock when it returns. | |
137 | */ | |
708d89f0 MD |
138 | static void wait_for_readers(struct cds_list_head *input_readers, |
139 | struct cds_list_head *cur_snap_readers, | |
140 | struct cds_list_head *qsreaders) | |
9f1621ca | 141 | { |
e198fb6a | 142 | unsigned int wait_loops = 0; |
02be5561 | 143 | struct rcu_reader *index, *tmp; |
9f1621ca | 144 | |
9f1621ca | 145 | /* |
f6b42f9c MD |
146 | * Wait for each thread URCU_TLS(rcu_reader).ctr to either |
147 | * indicate quiescence (offline), or for them to observe the | |
15302e28 | 148 | * current rcu_gp.ctr value. |
9f1621ca | 149 | */ |
4d703340 | 150 | for (;;) { |
f2aa4905 MD |
151 | if (wait_loops < RCU_QS_ACTIVE_ATTEMPTS) |
152 | wait_loops++; | |
83a2c421 | 153 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
15302e28 | 154 | uatomic_set(&rcu_gp.futex, -1); |
83a2c421 PB |
155 | /* |
156 | * Write futex before write waiting (the other side | |
157 | * reads them in the opposite order). | |
158 | */ | |
159 | cmm_smp_wmb(); | |
708d89f0 | 160 | cds_list_for_each_entry(index, input_readers, node) { |
83a2c421 PB |
161 | _CMM_STORE_SHARED(index->waiting, 1); |
162 | } | |
4d703340 | 163 | /* Write futex before read reader_gp */ |
5481ddb3 | 164 | cmm_smp_mb(); |
4d703340 | 165 | } |
708d89f0 MD |
166 | cds_list_for_each_entry_safe(index, tmp, input_readers, node) { |
167 | switch (rcu_reader_state(&index->ctr)) { | |
168 | case RCU_READER_ACTIVE_CURRENT: | |
169 | if (cur_snap_readers) { | |
170 | cds_list_move(&index->node, | |
171 | cur_snap_readers); | |
172 | break; | |
173 | } | |
174 | /* Fall-through */ | |
175 | case RCU_READER_INACTIVE: | |
176 | cds_list_move(&index->node, qsreaders); | |
177 | break; | |
178 | case RCU_READER_ACTIVE_OLD: | |
179 | /* | |
180 | * Old snapshot. Leaving node in | |
181 | * input_readers will make us busy-loop | |
182 | * until the snapshot becomes current or | |
183 | * the reader becomes inactive. | |
184 | */ | |
185 | break; | |
186 | } | |
4d703340 | 187 | } |
bc6c15bb | 188 | |
708d89f0 | 189 | if (cds_list_empty(input_readers)) { |
83a2c421 | 190 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4d703340 | 191 | /* Read reader_gp before write futex */ |
5481ddb3 | 192 | cmm_smp_mb(); |
15302e28 | 193 | uatomic_set(&rcu_gp.futex, 0); |
4d703340 MD |
194 | } |
195 | break; | |
196 | } else { | |
3c29ca5d MD |
197 | /* Temporarily unlock the registry lock. */ |
198 | mutex_unlock(&rcu_registry_lock); | |
83a2c421 | 199 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4d703340 | 200 | wait_gp(); |
bc6c15bb | 201 | } else { |
9f1621ca | 202 | #ifndef HAS_INCOHERENT_CACHES |
06f22bdb | 203 | caa_cpu_relax(); |
9f1621ca | 204 | #else /* #ifndef HAS_INCOHERENT_CACHES */ |
5481ddb3 | 205 | cmm_smp_mb(); |
9f1621ca | 206 | #endif /* #else #ifndef HAS_INCOHERENT_CACHES */ |
bc6c15bb | 207 | } |
3c29ca5d MD |
208 | /* Re-lock the registry lock before the next loop. */ |
209 | mutex_lock(&rcu_registry_lock); | |
bc6c15bb | 210 | } |
9f1621ca MD |
211 | } |
212 | } | |
213 | ||
47d2f29e MD |
214 | /* |
215 | * Using a two-subphases algorithm for architectures with smaller than 64-bit | |
216 | * long-size to ensure we do not encounter an overflow bug. | |
217 | */ | |
218 | ||
b39e1761 | 219 | #if (CAA_BITS_PER_LONG < 64) |
47d2f29e MD |
220 | void synchronize_rcu(void) |
221 | { | |
708d89f0 MD |
222 | CDS_LIST_HEAD(cur_snap_readers); |
223 | CDS_LIST_HEAD(qsreaders); | |
bc49c323 | 224 | unsigned long was_online; |
bf6822a6 MD |
225 | DEFINE_URCU_WAIT_NODE(wait, URCU_WAIT_WAITING); |
226 | struct urcu_waiters waiters; | |
bc49c323 | 227 | |
882f3357 | 228 | was_online = rcu_read_ongoing(); |
bc49c323 | 229 | |
47d2f29e | 230 | /* All threads should read qparity before accessing data structure |
27b940e7 PB |
231 | * where new ptr points to. In the "then" case, rcu_thread_offline |
232 | * includes a memory barrier. | |
233 | * | |
bc49c323 | 234 | * Mark the writer thread offline to make sure we don't wait for |
5e77fc1f PM |
235 | * our own quiescent state. This allows using synchronize_rcu() |
236 | * in threads registered as readers. | |
bc49c323 | 237 | */ |
27b940e7 PB |
238 | if (was_online) |
239 | rcu_thread_offline(); | |
240 | else | |
241 | cmm_smp_mb(); | |
bc49c323 | 242 | |
6362f68f | 243 | /* |
bf6822a6 | 244 | * Add ourself to gp_waiters queue of threads awaiting to wait |
6362f68f | 245 | * for a grace period. Proceed to perform the grace period only |
bf6822a6 | 246 | * if we are the first thread added into the queue. |
6362f68f | 247 | */ |
bf6822a6 MD |
248 | if (urcu_wait_add(&gp_waiters, &wait) != 0) { |
249 | /* Not first in queue: will be awakened by another thread. */ | |
250 | urcu_adaptative_busy_wait(&wait); | |
6362f68f MD |
251 | goto gp_end; |
252 | } | |
bf6822a6 MD |
253 | /* We won't need to wake ourself up */ |
254 | urcu_wait_set_state(&wait, URCU_WAIT_RUNNING); | |
6362f68f | 255 | |
6abb4bd5 | 256 | mutex_lock(&rcu_gp_lock); |
47d2f29e | 257 | |
6362f68f | 258 | /* |
bf6822a6 | 259 | * Move all waiters into our local queue. |
6362f68f | 260 | */ |
bf6822a6 | 261 | urcu_move_waiters(&waiters, &gp_waiters); |
6362f68f | 262 | |
3c29ca5d MD |
263 | mutex_lock(&rcu_registry_lock); |
264 | ||
16aa9ee8 | 265 | if (cds_list_empty(®istry)) |
2dfb8b5e | 266 | goto out; |
47d2f29e MD |
267 | |
268 | /* | |
f6b42f9c | 269 | * Wait for readers to observe original parity or be quiescent. |
3c29ca5d MD |
270 | * wait_for_readers() can release and grab again rcu_registry_lock |
271 | * interally. | |
47d2f29e | 272 | */ |
708d89f0 | 273 | wait_for_readers(®istry, &cur_snap_readers, &qsreaders); |
47d2f29e MD |
274 | |
275 | /* | |
f6b42f9c | 276 | * Must finish waiting for quiescent state for original parity |
15302e28 | 277 | * before committing next rcu_gp.ctr update to memory. Failure |
f6b42f9c | 278 | * to do so could result in the writer waiting forever while new |
5e77fc1f | 279 | * readers are always accessing data (no progress). Enforce |
f6b42f9c | 280 | * compiler-order of load URCU_TLS(rcu_reader).ctr before store |
15302e28 | 281 | * to rcu_gp.ctr. |
47d2f29e | 282 | */ |
5481ddb3 | 283 | cmm_barrier(); |
47d2f29e | 284 | |
47d2f29e | 285 | /* |
5481ddb3 | 286 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the |
2dfb8b5e MD |
287 | * model easier to understand. It does not have a big performance impact |
288 | * anyway, given this is the write-side. | |
47d2f29e | 289 | */ |
5481ddb3 | 290 | cmm_smp_mb(); |
47d2f29e | 291 | |
f6b42f9c | 292 | /* Switch parity: 0 -> 1, 1 -> 0 */ |
15302e28 | 293 | CMM_STORE_SHARED(rcu_gp.ctr, rcu_gp.ctr ^ RCU_GP_CTR); |
f6b42f9c | 294 | |
47d2f29e | 295 | /* |
15302e28 | 296 | * Must commit rcu_gp.ctr update to memory before waiting for |
f6b42f9c MD |
297 | * quiescent state. Failure to do so could result in the writer |
298 | * waiting forever while new readers are always accessing data | |
15302e28 | 299 | * (no progress). Enforce compiler-order of store to rcu_gp.ctr |
f6b42f9c | 300 | * before load URCU_TLS(rcu_reader).ctr. |
47d2f29e | 301 | */ |
f6b42f9c MD |
302 | cmm_barrier(); |
303 | ||
304 | /* | |
305 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the | |
306 | * model easier to understand. It does not have a big performance impact | |
307 | * anyway, given this is the write-side. | |
308 | */ | |
309 | cmm_smp_mb(); | |
310 | ||
311 | /* | |
312 | * Wait for readers to observe new parity or be quiescent. | |
3c29ca5d MD |
313 | * wait_for_readers() can release and grab again rcu_registry_lock |
314 | * interally. | |
f6b42f9c | 315 | */ |
708d89f0 MD |
316 | wait_for_readers(&cur_snap_readers, NULL, &qsreaders); |
317 | ||
318 | /* | |
319 | * Put quiescent reader list back into registry. | |
320 | */ | |
321 | cds_list_splice(&qsreaders, ®istry); | |
2dfb8b5e | 322 | out: |
3c29ca5d | 323 | mutex_unlock(&rcu_registry_lock); |
6abb4bd5 | 324 | mutex_unlock(&rcu_gp_lock); |
bf6822a6 | 325 | urcu_wake_all_waiters(&waiters); |
6362f68f | 326 | gp_end: |
bc49c323 MD |
327 | /* |
328 | * Finish waiting for reader threads before letting the old ptr being | |
47d2f29e MD |
329 | * freed. |
330 | */ | |
bc49c323 | 331 | if (was_online) |
27b940e7 PB |
332 | rcu_thread_online(); |
333 | else | |
334 | cmm_smp_mb(); | |
47d2f29e | 335 | } |
b39e1761 | 336 | #else /* !(CAA_BITS_PER_LONG < 64) */ |
9f1621ca MD |
337 | void synchronize_rcu(void) |
338 | { | |
708d89f0 | 339 | CDS_LIST_HEAD(qsreaders); |
f0f7dbdd | 340 | unsigned long was_online; |
bf6822a6 MD |
341 | DEFINE_URCU_WAIT_NODE(wait, URCU_WAIT_WAITING); |
342 | struct urcu_waiters waiters; | |
ff2f67a0 | 343 | |
882f3357 | 344 | was_online = rcu_read_ongoing(); |
ff2f67a0 MD |
345 | |
346 | /* | |
347 | * Mark the writer thread offline to make sure we don't wait for | |
5e77fc1f PM |
348 | * our own quiescent state. This allows using synchronize_rcu() |
349 | * in threads registered as readers. | |
ff2f67a0 | 350 | */ |
27b940e7 PB |
351 | if (was_online) |
352 | rcu_thread_offline(); | |
353 | else | |
354 | cmm_smp_mb(); | |
ff2f67a0 | 355 | |
6362f68f | 356 | /* |
bf6822a6 | 357 | * Add ourself to gp_waiters queue of threads awaiting to wait |
6362f68f | 358 | * for a grace period. Proceed to perform the grace period only |
bf6822a6 | 359 | * if we are the first thread added into the queue. |
6362f68f | 360 | */ |
bf6822a6 MD |
361 | if (urcu_wait_add(&gp_waiters, &wait) != 0) { |
362 | /* Not first in queue: will be awakened by another thread. */ | |
363 | urcu_adaptative_busy_wait(&wait); | |
6362f68f MD |
364 | goto gp_end; |
365 | } | |
bf6822a6 MD |
366 | /* We won't need to wake ourself up */ |
367 | urcu_wait_set_state(&wait, URCU_WAIT_RUNNING); | |
6362f68f | 368 | |
6abb4bd5 | 369 | mutex_lock(&rcu_gp_lock); |
6362f68f MD |
370 | |
371 | /* | |
bf6822a6 | 372 | * Move all waiters into our local queue. |
6362f68f | 373 | */ |
bf6822a6 | 374 | urcu_move_waiters(&waiters, &gp_waiters); |
6362f68f | 375 | |
3c29ca5d MD |
376 | mutex_lock(&rcu_registry_lock); |
377 | ||
16aa9ee8 | 378 | if (cds_list_empty(®istry)) |
2dfb8b5e | 379 | goto out; |
f6b42f9c MD |
380 | |
381 | /* Increment current G.P. */ | |
15302e28 | 382 | CMM_STORE_SHARED(rcu_gp.ctr, rcu_gp.ctr + RCU_GP_CTR); |
f6b42f9c MD |
383 | |
384 | /* | |
15302e28 | 385 | * Must commit rcu_gp.ctr update to memory before waiting for |
f6b42f9c MD |
386 | * quiescent state. Failure to do so could result in the writer |
387 | * waiting forever while new readers are always accessing data | |
15302e28 | 388 | * (no progress). Enforce compiler-order of store to rcu_gp.ctr |
f6b42f9c MD |
389 | * before load URCU_TLS(rcu_reader).ctr. |
390 | */ | |
391 | cmm_barrier(); | |
392 | ||
393 | /* | |
394 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the | |
395 | * model easier to understand. It does not have a big performance impact | |
396 | * anyway, given this is the write-side. | |
397 | */ | |
398 | cmm_smp_mb(); | |
399 | ||
400 | /* | |
401 | * Wait for readers to observe new count of be quiescent. | |
3c29ca5d MD |
402 | * wait_for_readers() can release and grab again rcu_registry_lock |
403 | * interally. | |
f6b42f9c | 404 | */ |
708d89f0 MD |
405 | wait_for_readers(®istry, NULL, &qsreaders); |
406 | ||
407 | /* | |
408 | * Put quiescent reader list back into registry. | |
409 | */ | |
410 | cds_list_splice(&qsreaders, ®istry); | |
2dfb8b5e | 411 | out: |
3c29ca5d | 412 | mutex_unlock(&rcu_registry_lock); |
6abb4bd5 | 413 | mutex_unlock(&rcu_gp_lock); |
bf6822a6 | 414 | urcu_wake_all_waiters(&waiters); |
6362f68f | 415 | gp_end: |
ff2f67a0 | 416 | if (was_online) |
27b940e7 PB |
417 | rcu_thread_online(); |
418 | else | |
419 | cmm_smp_mb(); | |
9f1621ca | 420 | } |
b39e1761 | 421 | #endif /* !(CAA_BITS_PER_LONG < 64) */ |
9f1621ca MD |
422 | |
423 | /* | |
424 | * library wrappers to be used by non-LGPL compatible source code. | |
425 | */ | |
426 | ||
427 | void rcu_read_lock(void) | |
428 | { | |
429 | _rcu_read_lock(); | |
430 | } | |
431 | ||
432 | void rcu_read_unlock(void) | |
433 | { | |
434 | _rcu_read_unlock(); | |
435 | } | |
436 | ||
882f3357 MD |
437 | int rcu_read_ongoing(void) |
438 | { | |
439 | return _rcu_read_ongoing(); | |
440 | } | |
441 | ||
7ac06cef MD |
442 | void rcu_quiescent_state(void) |
443 | { | |
444 | _rcu_quiescent_state(); | |
445 | } | |
446 | ||
447 | void rcu_thread_offline(void) | |
448 | { | |
449 | _rcu_thread_offline(); | |
450 | } | |
451 | ||
452 | void rcu_thread_online(void) | |
453 | { | |
454 | _rcu_thread_online(); | |
455 | } | |
456 | ||
9f1621ca MD |
457 | void rcu_register_thread(void) |
458 | { | |
bd252a04 MD |
459 | URCU_TLS(rcu_reader).tid = pthread_self(); |
460 | assert(URCU_TLS(rcu_reader).ctr == 0); | |
4f8e3380 | 461 | |
3c29ca5d | 462 | mutex_lock(&rcu_registry_lock); |
bd252a04 | 463 | cds_list_add(&URCU_TLS(rcu_reader).node, ®istry); |
3c29ca5d | 464 | mutex_unlock(&rcu_registry_lock); |
5f373c84 | 465 | _rcu_thread_online(); |
9f1621ca MD |
466 | } |
467 | ||
468 | void rcu_unregister_thread(void) | |
469 | { | |
76f3022f MD |
470 | /* |
471 | * We have to make the thread offline otherwise we end up dealocking | |
472 | * with a waiting writer. | |
473 | */ | |
474 | _rcu_thread_offline(); | |
3c29ca5d | 475 | mutex_lock(&rcu_registry_lock); |
bd252a04 | 476 | cds_list_del(&URCU_TLS(rcu_reader).node); |
3c29ca5d | 477 | mutex_unlock(&rcu_registry_lock); |
9f1621ca | 478 | } |
f6d18c64 MD |
479 | |
480 | void rcu_exit(void) | |
481 | { | |
01cadde4 MD |
482 | /* |
483 | * Assertion disabled because call_rcu threads are now rcu | |
484 | * readers, and left running at exit. | |
485 | * assert(cds_list_empty(®istry)); | |
486 | */ | |
f6d18c64 | 487 | } |
5e77fc1f | 488 | |
5e6b23a6 | 489 | DEFINE_RCU_FLAVOR(rcu_flavor); |
541d828d | 490 | |
5e77fc1f | 491 | #include "urcu-call-rcu-impl.h" |
0376e7b2 | 492 | #include "urcu-defer-impl.h" |