Commit | Line | Data |
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b57aee66 PM |
1 | /* |
2 | * urcu-call-rcu.c | |
3 | * | |
4 | * Userspace RCU library - batch memory reclamation with kernel API | |
5 | * | |
6 | * Copyright (c) 2010 Paul E. McKenney <paulmck@linux.vnet.ibm.com> | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
5161f31e | 23 | #define _LGPL_SOURCE |
b57aee66 PM |
24 | #include <stdio.h> |
25 | #include <pthread.h> | |
26 | #include <signal.h> | |
27 | #include <assert.h> | |
28 | #include <stdlib.h> | |
6d841bc2 | 29 | #include <stdint.h> |
b57aee66 PM |
30 | #include <string.h> |
31 | #include <errno.h> | |
32 | #include <poll.h> | |
33 | #include <sys/time.h> | |
b57aee66 | 34 | #include <unistd.h> |
c1d2c60b | 35 | #include <sched.h> |
b57aee66 | 36 | |
a47dd11c | 37 | #include "compat-getcpu.h" |
5161f31e | 38 | #include "urcu/wfcqueue.h" |
b57aee66 PM |
39 | #include "urcu-call-rcu.h" |
40 | #include "urcu-pointer.h" | |
3c24913f | 41 | #include "urcu/list.h" |
41849996 | 42 | #include "urcu/futex.h" |
bd252a04 | 43 | #include "urcu/tls-compat.h" |
81dd9134 | 44 | #include "urcu/ref.h" |
4a6d7378 | 45 | #include "urcu-die.h" |
b57aee66 | 46 | |
8e3690db MD |
47 | #define SET_AFFINITY_CHECK_PERIOD (1U << 8) /* 256 */ |
48 | #define SET_AFFINITY_CHECK_PERIOD_MASK (SET_AFFINITY_CHECK_PERIOD - 1) | |
49 | ||
b57aee66 PM |
50 | /* Data structure that identifies a call_rcu thread. */ |
51 | ||
52 | struct call_rcu_data { | |
5161f31e | 53 | /* |
0b8ab7df MD |
54 | * We do not align head on a different cache-line than tail |
55 | * mainly because call_rcu callback-invocation threads use | |
56 | * batching ("splice") to get an entire list of callbacks, which | |
57 | * effectively empties the queue, and requires to touch the tail | |
58 | * anyway. | |
5161f31e | 59 | */ |
b9f893b6 | 60 | struct cds_wfcq_tail cbs_tail; |
0b8ab7df | 61 | struct cds_wfcq_head cbs_head; |
b57aee66 | 62 | unsigned long flags; |
6d841bc2 | 63 | int32_t futex; |
73987721 | 64 | unsigned long qlen; /* maintained for debugging. */ |
b57aee66 | 65 | pthread_t tid; |
c1d2c60b | 66 | int cpu_affinity; |
8e3690db | 67 | unsigned long gp_count; |
3c24913f | 68 | struct cds_list_head list; |
b57aee66 PM |
69 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
70 | ||
b7f721d9 MD |
71 | struct call_rcu_completion { |
72 | int barrier_count; | |
73 | int32_t futex; | |
81dd9134 | 74 | struct urcu_ref ref; |
b7f721d9 MD |
75 | }; |
76 | ||
77 | struct call_rcu_completion_work { | |
78 | struct rcu_head head; | |
79 | struct call_rcu_completion *completion; | |
80 | }; | |
81 | ||
3c24913f PM |
82 | /* |
83 | * List of all call_rcu_data structures to keep valgrind happy. | |
84 | * Protected by call_rcu_mutex. | |
85 | */ | |
86 | ||
bab44e28 | 87 | static CDS_LIST_HEAD(call_rcu_data_list); |
3c24913f | 88 | |
b57aee66 PM |
89 | /* Link a thread using call_rcu() to its call_rcu thread. */ |
90 | ||
2f661865 | 91 | static DEFINE_URCU_TLS(struct call_rcu_data *, thread_call_rcu_data); |
b57aee66 | 92 | |
e85451a1 MD |
93 | /* |
94 | * Guard call_rcu thread creation and atfork handlers. | |
95 | */ | |
b57aee66 PM |
96 | static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER; |
97 | ||
98 | /* If a given thread does not have its own call_rcu thread, this is default. */ | |
99 | ||
100 | static struct call_rcu_data *default_call_rcu_data; | |
101 | ||
d0ec0ed2 MD |
102 | static struct urcu_atfork *registered_rculfhash_atfork; |
103 | static unsigned long registered_rculfhash_atfork_refcount; | |
104 | ||
b57aee66 PM |
105 | /* |
106 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
107 | * available, then we can have call_rcu threads assigned to individual | |
108 | * CPUs rather than only to specific threads. | |
109 | */ | |
110 | ||
a47dd11c | 111 | #if defined(HAVE_SYSCONF) && (defined(HAVE_SCHED_GETCPU) || defined(HAVE_GETCPUID)) |
b57aee66 PM |
112 | |
113 | /* | |
114 | * Pointer to array of pointers to per-CPU call_rcu_data structures | |
618b2595 MD |
115 | * and # CPUs. per_cpu_call_rcu_data is a RCU-protected pointer to an |
116 | * array of RCU-protected pointers to call_rcu_data. call_rcu acts as a | |
117 | * RCU read-side and reads per_cpu_call_rcu_data and the per-cpu pointer | |
118 | * without mutex. The call_rcu_mutex protects updates. | |
b57aee66 PM |
119 | */ |
120 | ||
121 | static struct call_rcu_data **per_cpu_call_rcu_data; | |
122 | static long maxcpus; | |
123 | ||
60af049d LJ |
124 | static void maxcpus_reset(void) |
125 | { | |
126 | maxcpus = 0; | |
127 | } | |
128 | ||
b57aee66 PM |
129 | /* Allocate the array if it has not already been allocated. */ |
130 | ||
131 | static void alloc_cpu_call_rcu_data(void) | |
132 | { | |
133 | struct call_rcu_data **p; | |
134 | static int warned = 0; | |
135 | ||
136 | if (maxcpus != 0) | |
137 | return; | |
138 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
139 | if (maxcpus <= 0) { | |
140 | return; | |
141 | } | |
142 | p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data)); | |
143 | if (p != NULL) { | |
144 | memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data)); | |
618b2595 | 145 | rcu_set_pointer(&per_cpu_call_rcu_data, p); |
b57aee66 PM |
146 | } else { |
147 | if (!warned) { | |
148 | fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n"); | |
149 | } | |
150 | warned = 1; | |
151 | } | |
152 | } | |
153 | ||
63b495d8 | 154 | #else /* #if defined(HAVE_SYSCONF) && defined(HAVE_SCHED_GETCPU) */ |
b57aee66 | 155 | |
f9437098 MD |
156 | /* |
157 | * per_cpu_call_rcu_data should be constant, but some functions below, used both | |
158 | * for cases where cpu number is available and not available, assume it it not | |
159 | * constant. | |
160 | */ | |
161 | static struct call_rcu_data **per_cpu_call_rcu_data = NULL; | |
b57aee66 PM |
162 | static const long maxcpus = -1; |
163 | ||
60af049d LJ |
164 | static void maxcpus_reset(void) |
165 | { | |
166 | } | |
167 | ||
b57aee66 PM |
168 | static void alloc_cpu_call_rcu_data(void) |
169 | { | |
170 | } | |
171 | ||
63b495d8 | 172 | #endif /* #else #if defined(HAVE_SYSCONF) && defined(HAVE_SCHED_GETCPU) */ |
b57aee66 PM |
173 | |
174 | /* Acquire the specified pthread mutex. */ | |
175 | ||
176 | static void call_rcu_lock(pthread_mutex_t *pmp) | |
177 | { | |
4a6d7378 MD |
178 | int ret; |
179 | ||
180 | ret = pthread_mutex_lock(pmp); | |
181 | if (ret) | |
182 | urcu_die(ret); | |
b57aee66 PM |
183 | } |
184 | ||
185 | /* Release the specified pthread mutex. */ | |
186 | ||
187 | static void call_rcu_unlock(pthread_mutex_t *pmp) | |
188 | { | |
4a6d7378 MD |
189 | int ret; |
190 | ||
191 | ret = pthread_mutex_unlock(pmp); | |
192 | if (ret) | |
193 | urcu_die(ret); | |
b57aee66 PM |
194 | } |
195 | ||
8e3690db MD |
196 | /* |
197 | * Periodically retry setting CPU affinity if we migrate. | |
198 | * Losing affinity can be caused by CPU hotunplug/hotplug, or by | |
199 | * cpuset(7). | |
200 | */ | |
c1d2c60b MD |
201 | #if HAVE_SCHED_SETAFFINITY |
202 | static | |
203 | int set_thread_cpu_affinity(struct call_rcu_data *crdp) | |
204 | { | |
205 | cpu_set_t mask; | |
8e3690db | 206 | int ret; |
c1d2c60b MD |
207 | |
208 | if (crdp->cpu_affinity < 0) | |
209 | return 0; | |
8e3690db MD |
210 | if (++crdp->gp_count & SET_AFFINITY_CHECK_PERIOD_MASK) |
211 | return 0; | |
212 | if (urcu_sched_getcpu() == crdp->cpu_affinity) | |
213 | return 0; | |
c1d2c60b MD |
214 | |
215 | CPU_ZERO(&mask); | |
216 | CPU_SET(crdp->cpu_affinity, &mask); | |
217 | #if SCHED_SETAFFINITY_ARGS == 2 | |
8e3690db | 218 | ret = sched_setaffinity(0, &mask); |
c1d2c60b | 219 | #else |
8e3690db | 220 | ret = sched_setaffinity(0, sizeof(mask), &mask); |
c1d2c60b | 221 | #endif |
8e3690db MD |
222 | /* |
223 | * EINVAL is fine: can be caused by hotunplugged CPUs, or by | |
224 | * cpuset(7). This is why we should always retry if we detect | |
225 | * migration. | |
226 | */ | |
227 | if (ret && errno == EINVAL) { | |
228 | ret = 0; | |
229 | errno = 0; | |
230 | } | |
231 | return ret; | |
c1d2c60b MD |
232 | } |
233 | #else | |
234 | static | |
235 | int set_thread_cpu_affinity(struct call_rcu_data *crdp) | |
236 | { | |
237 | return 0; | |
238 | } | |
239 | #endif | |
240 | ||
03fe58b3 MD |
241 | static void call_rcu_wait(struct call_rcu_data *crdp) |
242 | { | |
243 | /* Read call_rcu list before read futex */ | |
244 | cmm_smp_mb(); | |
b0a841b4 MD |
245 | if (uatomic_read(&crdp->futex) != -1) |
246 | return; | |
247 | while (futex_async(&crdp->futex, FUTEX_WAIT, -1, | |
248 | NULL, NULL, 0)) { | |
249 | switch (errno) { | |
250 | case EWOULDBLOCK: | |
251 | /* Value already changed. */ | |
252 | return; | |
253 | case EINTR: | |
254 | /* Retry if interrupted by signal. */ | |
255 | break; /* Get out of switch. */ | |
256 | default: | |
257 | /* Unexpected error. */ | |
258 | urcu_die(errno); | |
259 | } | |
260 | } | |
03fe58b3 MD |
261 | } |
262 | ||
263 | static void call_rcu_wake_up(struct call_rcu_data *crdp) | |
264 | { | |
265 | /* Write to call_rcu list before reading/writing futex */ | |
266 | cmm_smp_mb(); | |
a0b7f7ea | 267 | if (caa_unlikely(uatomic_read(&crdp->futex) == -1)) { |
03fe58b3 | 268 | uatomic_set(&crdp->futex, 0); |
b0a841b4 MD |
269 | if (futex_async(&crdp->futex, FUTEX_WAKE, 1, |
270 | NULL, NULL, 0) < 0) | |
271 | urcu_die(errno); | |
03fe58b3 MD |
272 | } |
273 | } | |
274 | ||
b7f721d9 MD |
275 | static void call_rcu_completion_wait(struct call_rcu_completion *completion) |
276 | { | |
277 | /* Read completion barrier count before read futex */ | |
278 | cmm_smp_mb(); | |
b0a841b4 MD |
279 | if (uatomic_read(&completion->futex) != -1) |
280 | return; | |
281 | while (futex_async(&completion->futex, FUTEX_WAIT, -1, | |
282 | NULL, NULL, 0)) { | |
283 | switch (errno) { | |
284 | case EWOULDBLOCK: | |
285 | /* Value already changed. */ | |
286 | return; | |
287 | case EINTR: | |
288 | /* Retry if interrupted by signal. */ | |
289 | break; /* Get out of switch. */ | |
290 | default: | |
291 | /* Unexpected error. */ | |
292 | urcu_die(errno); | |
293 | } | |
294 | } | |
b7f721d9 MD |
295 | } |
296 | ||
297 | static void call_rcu_completion_wake_up(struct call_rcu_completion *completion) | |
298 | { | |
299 | /* Write to completion barrier count before reading/writing futex */ | |
300 | cmm_smp_mb(); | |
301 | if (caa_unlikely(uatomic_read(&completion->futex) == -1)) { | |
302 | uatomic_set(&completion->futex, 0); | |
b0a841b4 MD |
303 | if (futex_async(&completion->futex, FUTEX_WAKE, 1, |
304 | NULL, NULL, 0) < 0) | |
305 | urcu_die(errno); | |
b7f721d9 MD |
306 | } |
307 | } | |
308 | ||
b57aee66 PM |
309 | /* This is the code run by each call_rcu thread. */ |
310 | ||
311 | static void *call_rcu_thread(void *arg) | |
312 | { | |
313 | unsigned long cbcount; | |
5161f31e | 314 | struct call_rcu_data *crdp = (struct call_rcu_data *) arg; |
2870aa1e | 315 | int rt = !!(uatomic_read(&crdp->flags) & URCU_CALL_RCU_RT); |
b57aee66 | 316 | |
8e3690db | 317 | if (set_thread_cpu_affinity(crdp)) |
4a6d7378 | 318 | urcu_die(errno); |
c1d2c60b | 319 | |
765f3ead MD |
320 | /* |
321 | * If callbacks take a read-side lock, we need to be registered. | |
322 | */ | |
323 | rcu_register_thread(); | |
324 | ||
bd252a04 | 325 | URCU_TLS(thread_call_rcu_data) = crdp; |
bc94ca9b MD |
326 | if (!rt) { |
327 | uatomic_dec(&crdp->futex); | |
328 | /* Decrement futex before reading call_rcu list */ | |
329 | cmm_smp_mb(); | |
330 | } | |
b57aee66 | 331 | for (;;) { |
5161f31e MD |
332 | struct cds_wfcq_head cbs_tmp_head; |
333 | struct cds_wfcq_tail cbs_tmp_tail; | |
334 | struct cds_wfcq_node *cbs, *cbs_tmp_n; | |
ae25b7e2 | 335 | enum cds_wfcq_ret splice_ret; |
5161f31e | 336 | |
8e3690db MD |
337 | if (set_thread_cpu_affinity(crdp)) |
338 | urcu_die(errno); | |
339 | ||
e85451a1 MD |
340 | if (uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSE) { |
341 | /* | |
342 | * Pause requested. Become quiescent: remove | |
343 | * ourself from all global lists, and don't | |
344 | * process any callback. The callback lists may | |
345 | * still be non-empty though. | |
346 | */ | |
347 | rcu_unregister_thread(); | |
348 | cmm_smp_mb__before_uatomic_or(); | |
349 | uatomic_or(&crdp->flags, URCU_CALL_RCU_PAUSED); | |
350 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSE) != 0) | |
109105b7 | 351 | (void) poll(NULL, 0, 1); |
fc236e5e KF |
352 | uatomic_and(&crdp->flags, ~URCU_CALL_RCU_PAUSED); |
353 | cmm_smp_mb__after_uatomic_and(); | |
e85451a1 MD |
354 | rcu_register_thread(); |
355 | } | |
356 | ||
5161f31e | 357 | cds_wfcq_init(&cbs_tmp_head, &cbs_tmp_tail); |
ae25b7e2 MD |
358 | splice_ret = __cds_wfcq_splice_blocking(&cbs_tmp_head, |
359 | &cbs_tmp_tail, &crdp->cbs_head, &crdp->cbs_tail); | |
360 | assert(splice_ret != CDS_WFCQ_RET_WOULDBLOCK); | |
361 | assert(splice_ret != CDS_WFCQ_RET_DEST_NON_EMPTY); | |
362 | if (splice_ret != CDS_WFCQ_RET_SRC_EMPTY) { | |
b57aee66 PM |
363 | synchronize_rcu(); |
364 | cbcount = 0; | |
5161f31e MD |
365 | __cds_wfcq_for_each_blocking_safe(&cbs_tmp_head, |
366 | &cbs_tmp_tail, cbs, cbs_tmp_n) { | |
367 | struct rcu_head *rhp; | |
368 | ||
369 | rhp = caa_container_of(cbs, | |
370 | struct rcu_head, next); | |
b57aee66 PM |
371 | rhp->func(rhp); |
372 | cbcount++; | |
5161f31e | 373 | } |
b57aee66 PM |
374 | uatomic_sub(&crdp->qlen, cbcount); |
375 | } | |
bc94ca9b MD |
376 | if (uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOP) |
377 | break; | |
765f3ead | 378 | rcu_thread_offline(); |
bc94ca9b | 379 | if (!rt) { |
5161f31e MD |
380 | if (cds_wfcq_empty(&crdp->cbs_head, |
381 | &crdp->cbs_tail)) { | |
bc94ca9b | 382 | call_rcu_wait(crdp); |
109105b7 | 383 | (void) poll(NULL, 0, 10); |
bc94ca9b | 384 | uatomic_dec(&crdp->futex); |
c768e45e | 385 | /* |
bc94ca9b MD |
386 | * Decrement futex before reading |
387 | * call_rcu list. | |
c768e45e MD |
388 | */ |
389 | cmm_smp_mb(); | |
ccbac24d | 390 | } else { |
109105b7 | 391 | (void) poll(NULL, 0, 10); |
c768e45e | 392 | } |
bc94ca9b | 393 | } else { |
109105b7 | 394 | (void) poll(NULL, 0, 10); |
b57aee66 | 395 | } |
765f3ead | 396 | rcu_thread_online(); |
bc94ca9b MD |
397 | } |
398 | if (!rt) { | |
399 | /* | |
400 | * Read call_rcu list before write futex. | |
401 | */ | |
402 | cmm_smp_mb(); | |
403 | uatomic_set(&crdp->futex, 0); | |
b57aee66 | 404 | } |
2870aa1e | 405 | uatomic_or(&crdp->flags, URCU_CALL_RCU_STOPPED); |
765f3ead | 406 | rcu_unregister_thread(); |
7106ddf8 | 407 | return NULL; |
b57aee66 PM |
408 | } |
409 | ||
410 | /* | |
411 | * Create both a call_rcu thread and the corresponding call_rcu_data | |
3c24913f PM |
412 | * structure, linking the structure in as specified. Caller must hold |
413 | * call_rcu_mutex. | |
b57aee66 PM |
414 | */ |
415 | ||
3c24913f | 416 | static void call_rcu_data_init(struct call_rcu_data **crdpp, |
c1d2c60b MD |
417 | unsigned long flags, |
418 | int cpu_affinity) | |
b57aee66 PM |
419 | { |
420 | struct call_rcu_data *crdp; | |
4a6d7378 | 421 | int ret; |
b57aee66 PM |
422 | |
423 | crdp = malloc(sizeof(*crdp)); | |
4a6d7378 MD |
424 | if (crdp == NULL) |
425 | urcu_die(errno); | |
b57aee66 | 426 | memset(crdp, '\0', sizeof(*crdp)); |
5161f31e | 427 | cds_wfcq_init(&crdp->cbs_head, &crdp->cbs_tail); |
b57aee66 | 428 | crdp->qlen = 0; |
263e3cf9 MD |
429 | crdp->futex = 0; |
430 | crdp->flags = flags; | |
3c24913f | 431 | cds_list_add(&crdp->list, &call_rcu_data_list); |
c1d2c60b | 432 | crdp->cpu_affinity = cpu_affinity; |
8e3690db | 433 | crdp->gp_count = 0; |
b57aee66 PM |
434 | cmm_smp_mb(); /* Structure initialized before pointer is planted. */ |
435 | *crdpp = crdp; | |
4a6d7378 MD |
436 | ret = pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp); |
437 | if (ret) | |
438 | urcu_die(ret); | |
b57aee66 PM |
439 | } |
440 | ||
441 | /* | |
442 | * Return a pointer to the call_rcu_data structure for the specified | |
443 | * CPU, returning NULL if there is none. We cannot automatically | |
444 | * created it because the platform we are running on might not define | |
63b495d8 | 445 | * urcu_sched_getcpu(). |
618b2595 MD |
446 | * |
447 | * The call to this function and use of the returned call_rcu_data | |
448 | * should be protected by RCU read-side lock. | |
b57aee66 PM |
449 | */ |
450 | ||
451 | struct call_rcu_data *get_cpu_call_rcu_data(int cpu) | |
452 | { | |
453 | static int warned = 0; | |
618b2595 | 454 | struct call_rcu_data **pcpu_crdp; |
b57aee66 | 455 | |
618b2595 MD |
456 | pcpu_crdp = rcu_dereference(per_cpu_call_rcu_data); |
457 | if (pcpu_crdp == NULL) | |
b57aee66 PM |
458 | return NULL; |
459 | if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) { | |
460 | fprintf(stderr, "[error] liburcu: get CPU # out of range\n"); | |
461 | warned = 1; | |
462 | } | |
463 | if (cpu < 0 || maxcpus <= cpu) | |
464 | return NULL; | |
618b2595 | 465 | return rcu_dereference(pcpu_crdp[cpu]); |
b57aee66 PM |
466 | } |
467 | ||
468 | /* | |
469 | * Return the tid corresponding to the call_rcu thread whose | |
470 | * call_rcu_data structure is specified. | |
471 | */ | |
472 | ||
473 | pthread_t get_call_rcu_thread(struct call_rcu_data *crdp) | |
474 | { | |
475 | return crdp->tid; | |
476 | } | |
477 | ||
478 | /* | |
479 | * Create a call_rcu_data structure (with thread) and return a pointer. | |
480 | */ | |
481 | ||
c1d2c60b MD |
482 | static struct call_rcu_data *__create_call_rcu_data(unsigned long flags, |
483 | int cpu_affinity) | |
b57aee66 PM |
484 | { |
485 | struct call_rcu_data *crdp; | |
486 | ||
c1d2c60b | 487 | call_rcu_data_init(&crdp, flags, cpu_affinity); |
b57aee66 PM |
488 | return crdp; |
489 | } | |
490 | ||
c1d2c60b MD |
491 | struct call_rcu_data *create_call_rcu_data(unsigned long flags, |
492 | int cpu_affinity) | |
3c24913f PM |
493 | { |
494 | struct call_rcu_data *crdp; | |
495 | ||
496 | call_rcu_lock(&call_rcu_mutex); | |
c1d2c60b | 497 | crdp = __create_call_rcu_data(flags, cpu_affinity); |
3c24913f PM |
498 | call_rcu_unlock(&call_rcu_mutex); |
499 | return crdp; | |
500 | } | |
501 | ||
b57aee66 PM |
502 | /* |
503 | * Set the specified CPU to use the specified call_rcu_data structure. | |
7106ddf8 PM |
504 | * |
505 | * Use NULL to remove a CPU's call_rcu_data structure, but it is | |
506 | * the caller's responsibility to dispose of the removed structure. | |
507 | * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure | |
508 | * (prior to NULLing it out, of course). | |
f9da0936 MD |
509 | * |
510 | * The caller must wait for a grace-period to pass between return from | |
511 | * set_cpu_call_rcu_data() and call to call_rcu_data_free() passing the | |
512 | * previous call rcu data as argument. | |
b57aee66 PM |
513 | */ |
514 | ||
515 | int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp) | |
516 | { | |
dcfc8165 | 517 | static int warned = 0; |
b57aee66 PM |
518 | |
519 | call_rcu_lock(&call_rcu_mutex); | |
f3776786 | 520 | alloc_cpu_call_rcu_data(); |
b57aee66 PM |
521 | if (cpu < 0 || maxcpus <= cpu) { |
522 | if (!warned) { | |
523 | fprintf(stderr, "[error] liburcu: set CPU # out of range\n"); | |
524 | warned = 1; | |
525 | } | |
526 | call_rcu_unlock(&call_rcu_mutex); | |
527 | errno = EINVAL; | |
528 | return -EINVAL; | |
529 | } | |
53a55535 | 530 | |
b57aee66 | 531 | if (per_cpu_call_rcu_data == NULL) { |
3670fef2 | 532 | call_rcu_unlock(&call_rcu_mutex); |
b57aee66 PM |
533 | errno = ENOMEM; |
534 | return -ENOMEM; | |
535 | } | |
53a55535 LJ |
536 | |
537 | if (per_cpu_call_rcu_data[cpu] != NULL && crdp != NULL) { | |
538 | call_rcu_unlock(&call_rcu_mutex); | |
539 | errno = EEXIST; | |
540 | return -EEXIST; | |
541 | } | |
542 | ||
618b2595 | 543 | rcu_set_pointer(&per_cpu_call_rcu_data[cpu], crdp); |
3670fef2 | 544 | call_rcu_unlock(&call_rcu_mutex); |
b57aee66 PM |
545 | return 0; |
546 | } | |
547 | ||
548 | /* | |
549 | * Return a pointer to the default call_rcu_data structure, creating | |
550 | * one if need be. Because we never free call_rcu_data structures, | |
551 | * we don't need to be in an RCU read-side critical section. | |
552 | */ | |
553 | ||
554 | struct call_rcu_data *get_default_call_rcu_data(void) | |
555 | { | |
556 | if (default_call_rcu_data != NULL) | |
557 | return rcu_dereference(default_call_rcu_data); | |
558 | call_rcu_lock(&call_rcu_mutex); | |
559 | if (default_call_rcu_data != NULL) { | |
560 | call_rcu_unlock(&call_rcu_mutex); | |
561 | return default_call_rcu_data; | |
562 | } | |
c1d2c60b | 563 | call_rcu_data_init(&default_call_rcu_data, 0, -1); |
b57aee66 PM |
564 | call_rcu_unlock(&call_rcu_mutex); |
565 | return default_call_rcu_data; | |
566 | } | |
567 | ||
568 | /* | |
569 | * Return the call_rcu_data structure that applies to the currently | |
570 | * running thread. Any call_rcu_data structure assigned specifically | |
571 | * to this thread has first priority, followed by any call_rcu_data | |
572 | * structure assigned to the CPU on which the thread is running, | |
573 | * followed by the default call_rcu_data structure. If there is not | |
574 | * yet a default call_rcu_data structure, one will be created. | |
618b2595 MD |
575 | * |
576 | * Calls to this function and use of the returned call_rcu_data should | |
577 | * be protected by RCU read-side lock. | |
b57aee66 PM |
578 | */ |
579 | struct call_rcu_data *get_call_rcu_data(void) | |
580 | { | |
9744f3bb | 581 | struct call_rcu_data *crd; |
b57aee66 | 582 | |
bd252a04 MD |
583 | if (URCU_TLS(thread_call_rcu_data) != NULL) |
584 | return URCU_TLS(thread_call_rcu_data); | |
9744f3bb LJ |
585 | |
586 | if (maxcpus > 0) { | |
63b495d8 | 587 | crd = get_cpu_call_rcu_data(urcu_sched_getcpu()); |
9744f3bb LJ |
588 | if (crd) |
589 | return crd; | |
b57aee66 | 590 | } |
9744f3bb | 591 | |
b57aee66 PM |
592 | return get_default_call_rcu_data(); |
593 | } | |
594 | ||
595 | /* | |
596 | * Return a pointer to this task's call_rcu_data if there is one. | |
597 | */ | |
598 | ||
599 | struct call_rcu_data *get_thread_call_rcu_data(void) | |
600 | { | |
bd252a04 | 601 | return URCU_TLS(thread_call_rcu_data); |
b57aee66 PM |
602 | } |
603 | ||
604 | /* | |
605 | * Set this task's call_rcu_data structure as specified, regardless | |
606 | * of whether or not this task already had one. (This allows switching | |
607 | * to and from real-time call_rcu threads, for example.) | |
7106ddf8 PM |
608 | * |
609 | * Use NULL to remove a thread's call_rcu_data structure, but it is | |
610 | * the caller's responsibility to dispose of the removed structure. | |
611 | * Use get_thread_call_rcu_data() to obtain a pointer to the old structure | |
612 | * (prior to NULLing it out, of course). | |
b57aee66 PM |
613 | */ |
614 | ||
615 | void set_thread_call_rcu_data(struct call_rcu_data *crdp) | |
616 | { | |
bd252a04 | 617 | URCU_TLS(thread_call_rcu_data) = crdp; |
b57aee66 PM |
618 | } |
619 | ||
620 | /* | |
621 | * Create a separate call_rcu thread for each CPU. This does not | |
622 | * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data() | |
0938c541 MD |
623 | * function if you want that behavior. Should be paired with |
624 | * free_all_cpu_call_rcu_data() to teardown these call_rcu worker | |
625 | * threads. | |
b57aee66 PM |
626 | */ |
627 | ||
628 | int create_all_cpu_call_rcu_data(unsigned long flags) | |
629 | { | |
630 | int i; | |
631 | struct call_rcu_data *crdp; | |
632 | int ret; | |
633 | ||
634 | call_rcu_lock(&call_rcu_mutex); | |
635 | alloc_cpu_call_rcu_data(); | |
636 | call_rcu_unlock(&call_rcu_mutex); | |
637 | if (maxcpus <= 0) { | |
638 | errno = EINVAL; | |
639 | return -EINVAL; | |
640 | } | |
641 | if (per_cpu_call_rcu_data == NULL) { | |
642 | errno = ENOMEM; | |
643 | return -ENOMEM; | |
644 | } | |
645 | for (i = 0; i < maxcpus; i++) { | |
646 | call_rcu_lock(&call_rcu_mutex); | |
647 | if (get_cpu_call_rcu_data(i)) { | |
648 | call_rcu_unlock(&call_rcu_mutex); | |
649 | continue; | |
650 | } | |
c1d2c60b | 651 | crdp = __create_call_rcu_data(flags, i); |
b57aee66 PM |
652 | if (crdp == NULL) { |
653 | call_rcu_unlock(&call_rcu_mutex); | |
654 | errno = ENOMEM; | |
655 | return -ENOMEM; | |
656 | } | |
657 | call_rcu_unlock(&call_rcu_mutex); | |
658 | if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) { | |
356c8794 LJ |
659 | call_rcu_data_free(crdp); |
660 | ||
661 | /* it has been created by other thread */ | |
662 | if (ret == -EEXIST) | |
663 | continue; | |
664 | ||
665 | return ret; | |
b57aee66 PM |
666 | } |
667 | } | |
668 | return 0; | |
669 | } | |
670 | ||
7106ddf8 PM |
671 | /* |
672 | * Wake up the call_rcu thread corresponding to the specified | |
673 | * call_rcu_data structure. | |
674 | */ | |
675 | static void wake_call_rcu_thread(struct call_rcu_data *crdp) | |
676 | { | |
263e3cf9 MD |
677 | if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) |
678 | call_rcu_wake_up(crdp); | |
7106ddf8 PM |
679 | } |
680 | ||
b7f721d9 MD |
681 | static void _call_rcu(struct rcu_head *head, |
682 | void (*func)(struct rcu_head *head), | |
683 | struct call_rcu_data *crdp) | |
684 | { | |
685 | cds_wfcq_node_init(&head->next); | |
686 | head->func = func; | |
687 | cds_wfcq_enqueue(&crdp->cbs_head, &crdp->cbs_tail, &head->next); | |
688 | uatomic_inc(&crdp->qlen); | |
689 | wake_call_rcu_thread(crdp); | |
690 | } | |
691 | ||
b57aee66 PM |
692 | /* |
693 | * Schedule a function to be invoked after a following grace period. | |
694 | * This is the only function that must be called -- the others are | |
695 | * only present to allow applications to tune their use of RCU for | |
696 | * maximum performance. | |
697 | * | |
698 | * Note that unless a call_rcu thread has not already been created, | |
699 | * the first invocation of call_rcu() will create one. So, if you | |
700 | * need the first invocation of call_rcu() to be fast, make sure | |
701 | * to create a call_rcu thread first. One way to accomplish this is | |
702 | * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data(). | |
618b2595 MD |
703 | * |
704 | * call_rcu must be called by registered RCU read-side threads. | |
b57aee66 | 705 | */ |
b57aee66 PM |
706 | void call_rcu(struct rcu_head *head, |
707 | void (*func)(struct rcu_head *head)) | |
708 | { | |
709 | struct call_rcu_data *crdp; | |
710 | ||
618b2595 | 711 | /* Holding rcu read-side lock across use of per-cpu crdp */ |
ffb4aaa7 | 712 | _rcu_read_lock(); |
b57aee66 | 713 | crdp = get_call_rcu_data(); |
b7f721d9 | 714 | _call_rcu(head, func, crdp); |
ffb4aaa7 | 715 | _rcu_read_unlock(); |
7106ddf8 PM |
716 | } |
717 | ||
718 | /* | |
719 | * Free up the specified call_rcu_data structure, terminating the | |
720 | * associated call_rcu thread. The caller must have previously | |
721 | * removed the call_rcu_data structure from per-thread or per-CPU | |
722 | * usage. For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU | |
723 | * call_rcu_data structures or set_thread_call_rcu_data(NULL) for | |
724 | * per-thread call_rcu_data structures. | |
725 | * | |
726 | * We silently refuse to free up the default call_rcu_data structure | |
727 | * because that is where we put any leftover callbacks. Note that | |
728 | * the possibility of self-spawning callbacks makes it impossible | |
729 | * to execute all the callbacks in finite time without putting any | |
730 | * newly spawned callbacks somewhere else. The "somewhere else" of | |
731 | * last resort is the default call_rcu_data structure. | |
732 | * | |
733 | * We also silently refuse to free NULL pointers. This simplifies | |
734 | * the calling code. | |
f9da0936 MD |
735 | * |
736 | * The caller must wait for a grace-period to pass between return from | |
737 | * set_cpu_call_rcu_data() and call to call_rcu_data_free() passing the | |
738 | * previous call rcu data as argument. | |
03e5118f MD |
739 | * |
740 | * Note: introducing __cds_wfcq_splice_blocking() in this function fixed | |
741 | * a list corruption bug in the 0.7.x series. The equivalent fix | |
742 | * appeared in 0.6.8 for the stable-0.6 branch. | |
7106ddf8 PM |
743 | */ |
744 | void call_rcu_data_free(struct call_rcu_data *crdp) | |
745 | { | |
7106ddf8 PM |
746 | if (crdp == NULL || crdp == default_call_rcu_data) { |
747 | return; | |
748 | } | |
2870aa1e PB |
749 | if ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOPPED) == 0) { |
750 | uatomic_or(&crdp->flags, URCU_CALL_RCU_STOP); | |
7106ddf8 | 751 | wake_call_rcu_thread(crdp); |
2870aa1e | 752 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOPPED) == 0) |
109105b7 | 753 | (void) poll(NULL, 0, 1); |
7106ddf8 | 754 | } |
5161f31e | 755 | if (!cds_wfcq_empty(&crdp->cbs_head, &crdp->cbs_tail)) { |
698d0778 MD |
756 | /* Create default call rcu data if need be */ |
757 | (void) get_default_call_rcu_data(); | |
5161f31e MD |
758 | __cds_wfcq_splice_blocking(&default_call_rcu_data->cbs_head, |
759 | &default_call_rcu_data->cbs_tail, | |
760 | &crdp->cbs_head, &crdp->cbs_tail); | |
7106ddf8 PM |
761 | uatomic_add(&default_call_rcu_data->qlen, |
762 | uatomic_read(&crdp->qlen)); | |
1e92aa15 | 763 | wake_call_rcu_thread(default_call_rcu_data); |
7106ddf8 | 764 | } |
59dc9e9d | 765 | |
b75dffe6 | 766 | call_rcu_lock(&call_rcu_mutex); |
59dc9e9d | 767 | cds_list_del(&crdp->list); |
b75dffe6 LJ |
768 | call_rcu_unlock(&call_rcu_mutex); |
769 | ||
59dc9e9d | 770 | free(crdp); |
7106ddf8 PM |
771 | } |
772 | ||
773 | /* | |
774 | * Clean up all the per-CPU call_rcu threads. | |
775 | */ | |
776 | void free_all_cpu_call_rcu_data(void) | |
777 | { | |
778 | int cpu; | |
618b2595 MD |
779 | struct call_rcu_data **crdp; |
780 | static int warned = 0; | |
7106ddf8 PM |
781 | |
782 | if (maxcpus <= 0) | |
783 | return; | |
618b2595 MD |
784 | |
785 | crdp = malloc(sizeof(*crdp) * maxcpus); | |
786 | if (!crdp) { | |
787 | if (!warned) { | |
788 | fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n"); | |
789 | } | |
790 | warned = 1; | |
d31150b4 | 791 | return; |
618b2595 MD |
792 | } |
793 | ||
7106ddf8 | 794 | for (cpu = 0; cpu < maxcpus; cpu++) { |
618b2595 MD |
795 | crdp[cpu] = get_cpu_call_rcu_data(cpu); |
796 | if (crdp[cpu] == NULL) | |
7106ddf8 PM |
797 | continue; |
798 | set_cpu_call_rcu_data(cpu, NULL); | |
7106ddf8 | 799 | } |
618b2595 MD |
800 | /* |
801 | * Wait for call_rcu sites acting as RCU readers of the | |
802 | * call_rcu_data to become quiescent. | |
803 | */ | |
804 | synchronize_rcu(); | |
805 | for (cpu = 0; cpu < maxcpus; cpu++) { | |
806 | if (crdp[cpu] == NULL) | |
807 | continue; | |
808 | call_rcu_data_free(crdp[cpu]); | |
809 | } | |
810 | free(crdp); | |
7106ddf8 PM |
811 | } |
812 | ||
81dd9134 KF |
813 | static |
814 | void free_completion(struct urcu_ref *ref) | |
815 | { | |
816 | struct call_rcu_completion *completion; | |
817 | ||
818 | completion = caa_container_of(ref, struct call_rcu_completion, ref); | |
819 | free(completion); | |
820 | } | |
821 | ||
b7f721d9 MD |
822 | static |
823 | void _rcu_barrier_complete(struct rcu_head *head) | |
824 | { | |
825 | struct call_rcu_completion_work *work; | |
826 | struct call_rcu_completion *completion; | |
827 | ||
828 | work = caa_container_of(head, struct call_rcu_completion_work, head); | |
829 | completion = work->completion; | |
81dd9134 KF |
830 | if (!uatomic_sub_return(&completion->barrier_count, 1)) |
831 | call_rcu_completion_wake_up(completion); | |
832 | urcu_ref_put(&completion->ref, free_completion); | |
b7f721d9 MD |
833 | free(work); |
834 | } | |
835 | ||
836 | /* | |
837 | * Wait for all in-flight call_rcu callbacks to complete execution. | |
838 | */ | |
839 | void rcu_barrier(void) | |
840 | { | |
841 | struct call_rcu_data *crdp; | |
81dd9134 | 842 | struct call_rcu_completion *completion; |
63f0fc6d | 843 | int count = 0; |
b7f721d9 MD |
844 | int was_online; |
845 | ||
846 | /* Put in offline state in QSBR. */ | |
ffb4aaa7 | 847 | was_online = _rcu_read_ongoing(); |
b7f721d9 MD |
848 | if (was_online) |
849 | rcu_thread_offline(); | |
850 | /* | |
851 | * Calling a rcu_barrier() within a RCU read-side critical | |
852 | * section is an error. | |
853 | */ | |
ffb4aaa7 | 854 | if (_rcu_read_ongoing()) { |
b7f721d9 MD |
855 | static int warned = 0; |
856 | ||
857 | if (!warned) { | |
858 | fprintf(stderr, "[error] liburcu: rcu_barrier() called from within RCU read-side critical section.\n"); | |
859 | } | |
860 | warned = 1; | |
861 | goto online; | |
862 | } | |
863 | ||
81dd9134 KF |
864 | completion = calloc(sizeof(*completion), 1); |
865 | if (!completion) | |
866 | urcu_die(errno); | |
867 | ||
b7f721d9 MD |
868 | call_rcu_lock(&call_rcu_mutex); |
869 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) | |
870 | count++; | |
871 | ||
81dd9134 KF |
872 | /* Referenced by rcu_barrier() and each call_rcu thread. */ |
873 | urcu_ref_set(&completion->ref, count + 1); | |
874 | completion->barrier_count = count; | |
b7f721d9 MD |
875 | |
876 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { | |
877 | struct call_rcu_completion_work *work; | |
878 | ||
879 | work = calloc(sizeof(*work), 1); | |
63f0fc6d MD |
880 | if (!work) |
881 | urcu_die(errno); | |
81dd9134 | 882 | work->completion = completion; |
b7f721d9 | 883 | _call_rcu(&work->head, _rcu_barrier_complete, crdp); |
b7f721d9 MD |
884 | } |
885 | call_rcu_unlock(&call_rcu_mutex); | |
886 | ||
b7f721d9 MD |
887 | /* Wait for them */ |
888 | for (;;) { | |
81dd9134 | 889 | uatomic_dec(&completion->futex); |
b7f721d9 MD |
890 | /* Decrement futex before reading barrier_count */ |
891 | cmm_smp_mb(); | |
81dd9134 | 892 | if (!uatomic_read(&completion->barrier_count)) |
b7f721d9 | 893 | break; |
81dd9134 | 894 | call_rcu_completion_wait(completion); |
b7f721d9 | 895 | } |
81dd9134 KF |
896 | |
897 | urcu_ref_put(&completion->ref, free_completion); | |
898 | ||
b7f721d9 MD |
899 | online: |
900 | if (was_online) | |
901 | rcu_thread_online(); | |
902 | } | |
903 | ||
81ad2e19 PM |
904 | /* |
905 | * Acquire the call_rcu_mutex in order to ensure that the child sees | |
e85451a1 MD |
906 | * all of the call_rcu() data structures in a consistent state. Ensure |
907 | * that all call_rcu threads are in a quiescent state across fork. | |
81ad2e19 PM |
908 | * Suitable for pthread_atfork() and friends. |
909 | */ | |
910 | void call_rcu_before_fork(void) | |
911 | { | |
e85451a1 | 912 | struct call_rcu_data *crdp; |
d0ec0ed2 | 913 | struct urcu_atfork *atfork; |
e85451a1 | 914 | |
81ad2e19 | 915 | call_rcu_lock(&call_rcu_mutex); |
e85451a1 | 916 | |
d0ec0ed2 MD |
917 | atfork = registered_rculfhash_atfork; |
918 | if (atfork) | |
919 | atfork->before_fork(atfork->priv); | |
920 | ||
e85451a1 MD |
921 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { |
922 | uatomic_or(&crdp->flags, URCU_CALL_RCU_PAUSE); | |
923 | cmm_smp_mb__after_uatomic_or(); | |
924 | wake_call_rcu_thread(crdp); | |
925 | } | |
926 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { | |
927 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSED) == 0) | |
109105b7 | 928 | (void) poll(NULL, 0, 1); |
e85451a1 | 929 | } |
81ad2e19 PM |
930 | } |
931 | ||
932 | /* | |
933 | * Clean up call_rcu data structures in the parent of a successful fork() | |
934 | * that is not followed by exec() in the child. Suitable for | |
935 | * pthread_atfork() and friends. | |
936 | */ | |
937 | void call_rcu_after_fork_parent(void) | |
938 | { | |
e85451a1 | 939 | struct call_rcu_data *crdp; |
d0ec0ed2 | 940 | struct urcu_atfork *atfork; |
e85451a1 MD |
941 | |
942 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) | |
943 | uatomic_and(&crdp->flags, ~URCU_CALL_RCU_PAUSE); | |
fc236e5e KF |
944 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { |
945 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSED) != 0) | |
109105b7 | 946 | (void) poll(NULL, 0, 1); |
fc236e5e | 947 | } |
d0ec0ed2 MD |
948 | atfork = registered_rculfhash_atfork; |
949 | if (atfork) | |
950 | atfork->after_fork_parent(atfork->priv); | |
81ad2e19 PM |
951 | call_rcu_unlock(&call_rcu_mutex); |
952 | } | |
953 | ||
7106ddf8 PM |
954 | /* |
955 | * Clean up call_rcu data structures in the child of a successful fork() | |
81ad2e19 PM |
956 | * that is not followed by exec(). Suitable for pthread_atfork() and |
957 | * friends. | |
7106ddf8 PM |
958 | */ |
959 | void call_rcu_after_fork_child(void) | |
960 | { | |
077ff173 | 961 | struct call_rcu_data *crdp, *next; |
d0ec0ed2 | 962 | struct urcu_atfork *atfork; |
7106ddf8 | 963 | |
81ad2e19 PM |
964 | /* Release the mutex. */ |
965 | call_rcu_unlock(&call_rcu_mutex); | |
966 | ||
d0ec0ed2 MD |
967 | atfork = registered_rculfhash_atfork; |
968 | if (atfork) | |
969 | atfork->after_fork_child(atfork->priv); | |
970 | ||
ad1b9909 LJ |
971 | /* Do nothing when call_rcu() has not been used */ |
972 | if (cds_list_empty(&call_rcu_data_list)) | |
973 | return; | |
974 | ||
7106ddf8 PM |
975 | /* |
976 | * Allocate a new default call_rcu_data structure in order | |
977 | * to get a working call_rcu thread to go with it. | |
978 | */ | |
979 | default_call_rcu_data = NULL; | |
980 | (void)get_default_call_rcu_data(); | |
981 | ||
60af049d LJ |
982 | /* Cleanup call_rcu_data pointers before use */ |
983 | maxcpus_reset(); | |
984 | free(per_cpu_call_rcu_data); | |
618b2595 | 985 | rcu_set_pointer(&per_cpu_call_rcu_data, NULL); |
bd252a04 | 986 | URCU_TLS(thread_call_rcu_data) = NULL; |
60af049d | 987 | |
e85451a1 MD |
988 | /* |
989 | * Dispose of all of the rest of the call_rcu_data structures. | |
990 | * Leftover call_rcu callbacks will be merged into the new | |
991 | * default call_rcu thread queue. | |
992 | */ | |
077ff173 | 993 | cds_list_for_each_entry_safe(crdp, next, &call_rcu_data_list, list) { |
7106ddf8 | 994 | if (crdp == default_call_rcu_data) |
077ff173 | 995 | continue; |
2870aa1e | 996 | uatomic_set(&crdp->flags, URCU_CALL_RCU_STOPPED); |
7106ddf8 | 997 | call_rcu_data_free(crdp); |
b57aee66 PM |
998 | } |
999 | } | |
d0ec0ed2 MD |
1000 | |
1001 | void urcu_register_rculfhash_atfork(struct urcu_atfork *atfork) | |
1002 | { | |
1003 | call_rcu_lock(&call_rcu_mutex); | |
1004 | if (registered_rculfhash_atfork_refcount++) | |
1005 | goto end; | |
1006 | registered_rculfhash_atfork = atfork; | |
1007 | end: | |
1008 | call_rcu_unlock(&call_rcu_mutex); | |
1009 | } | |
1010 | ||
1011 | void urcu_unregister_rculfhash_atfork(struct urcu_atfork *atfork) | |
1012 | { | |
1013 | call_rcu_lock(&call_rcu_mutex); | |
1014 | if (--registered_rculfhash_atfork_refcount) | |
1015 | goto end; | |
1016 | registered_rculfhash_atfork = NULL; | |
1017 | end: | |
1018 | call_rcu_unlock(&call_rcu_mutex); | |
1019 | } |