1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Read-Copy Update definitions shared among RCU implementations.
4 *
5 * Copyright IBM Corporation, 2011
6 *
7 * Author: Paul E. McKenney <paulmck@linux.ibm.com>
8 */
9
10 #ifndef __LINUX_RCU_H
11 #define __LINUX_RCU_H
12
13 #include <linux/slab.h>
14 #include <trace/events/rcu.h>
15
16 /*
17 * Grace-period counter management.
18 *
19 * The two least significant bits contain the control flags.
20 * The most significant bits contain the grace-period sequence counter.
21 *
22 * When both control flags are zero, no grace period is in progress.
23 * When either bit is non-zero, a grace period has started and is in
24 * progress. When the grace period completes, the control flags are reset
25 * to 0 and the grace-period sequence counter is incremented.
26 *
27 * However some specific RCU usages make use of custom values.
28 *
29 * SRCU special control values:
30 *
31 * SRCU_SNP_INIT_SEQ : Invalid/init value set when SRCU node
32 * is initialized.
33 *
34 * SRCU_STATE_IDLE : No SRCU gp is in progress
35 *
36 * SRCU_STATE_SCAN1 : State set by rcu_seq_start(). Indicates
37 * we are scanning the readers on the slot
38 * defined as inactive (there might well
39 * be pending readers that will use that
40 * index, but their number is bounded).
41 *
42 * SRCU_STATE_SCAN2 : State set manually via rcu_seq_set_state()
43 * Indicates we are flipping the readers
44 * index and then scanning the readers on the
45 * slot newly designated as inactive (again,
46 * the number of pending readers that will use
47 * this inactive index is bounded).
48 *
49 * RCU polled GP special control value:
50 *
51 * RCU_GET_STATE_COMPLETED : State value indicating an already-completed
52 * polled GP has completed. This value covers
53 * both the state and the counter of the
54 * grace-period sequence number.
55 */
56
57 #define RCU_SEQ_CTR_SHIFT 2
58 #define RCU_SEQ_STATE_MASK ((1 << RCU_SEQ_CTR_SHIFT) - 1)
59
60 /* Low-order bit definition for polled grace-period APIs. */
61 #define RCU_GET_STATE_COMPLETED 0x1
62
63 extern int sysctl_sched_rt_runtime;
64
65 /*
66 * Return the counter portion of a sequence number previously returned
67 * by rcu_seq_snap() or rcu_seq_current().
68 */
69 static inline unsigned long rcu_seq_ctr(unsigned long s)
70 {
71 return s >> RCU_SEQ_CTR_SHIFT;
72 }
73
74 /*
75 * Return the state portion of a sequence number previously returned
76 * by rcu_seq_snap() or rcu_seq_current().
77 */
78 static inline int rcu_seq_state(unsigned long s)
79 {
80 return s & RCU_SEQ_STATE_MASK;
81 }
82
83 /*
84 * Set the state portion of the pointed-to sequence number.
85 * The caller is responsible for preventing conflicting updates.
86 */
87 static inline void rcu_seq_set_state(unsigned long *sp, int newstate)
88 {
89 WARN_ON_ONCE(newstate & ~RCU_SEQ_STATE_MASK);
90 WRITE_ONCE(*sp, (*sp & ~RCU_SEQ_STATE_MASK) + newstate);
91 }
92
93 /* Adjust sequence number for start of update-side operation. */
94 static inline void rcu_seq_start(unsigned long *sp)
95 {
96 WRITE_ONCE(*sp, *sp + 1);
97 smp_mb(); /* Ensure update-side operation after counter increment. */
98 WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
99 }
100
101 /* Compute the end-of-grace-period value for the specified sequence number. */
102 static inline unsigned long rcu_seq_endval(unsigned long *sp)
103 {
104 return (*sp | RCU_SEQ_STATE_MASK) + 1;
105 }
106
107 /* Adjust sequence number for end of update-side operation. */
108 static inline void rcu_seq_end(unsigned long *sp)
109 {
110 smp_mb(); /* Ensure update-side operation before counter increment. */
111 WARN_ON_ONCE(!rcu_seq_state(*sp));
112 WRITE_ONCE(*sp, rcu_seq_endval(sp));
113 }
114
115 /*
116 * rcu_seq_snap - Take a snapshot of the update side's sequence number.
117 *
118 * This function returns the earliest value of the grace-period sequence number
119 * that will indicate that a full grace period has elapsed since the current
120 * time. Once the grace-period sequence number has reached this value, it will
121 * be safe to invoke all callbacks that have been registered prior to the
122 * current time. This value is the current grace-period number plus two to the
123 * power of the number of low-order bits reserved for state, then rounded up to
124 * the next value in which the state bits are all zero.
125 */
126 static inline unsigned long rcu_seq_snap(unsigned long *sp)
127 {
128 unsigned long s;
129
130 s = (READ_ONCE(*sp) + 2 * RCU_SEQ_STATE_MASK + 1) & ~RCU_SEQ_STATE_MASK;
131 smp_mb(); /* Above access must not bleed into critical section. */
132 return s;
133 }
134
135 /* Return the current value the update side's sequence number, no ordering. */
136 static inline unsigned long rcu_seq_current(unsigned long *sp)
137 {
138 return READ_ONCE(*sp);
139 }
140
141 /*
142 * Given a snapshot from rcu_seq_snap(), determine whether or not the
143 * corresponding update-side operation has started.
144 */
145 static inline bool rcu_seq_started(unsigned long *sp, unsigned long s)
146 {
147 return ULONG_CMP_LT((s - 1) & ~RCU_SEQ_STATE_MASK, READ_ONCE(*sp));
148 }
149
150 /*
151 * Given a snapshot from rcu_seq_snap(), determine whether or not a
152 * full update-side operation has occurred.
153 */
154 static inline bool rcu_seq_done(unsigned long *sp, unsigned long s)
155 {
156 return ULONG_CMP_GE(READ_ONCE(*sp), s);
157 }
158
159 /*
160 * Given a snapshot from rcu_seq_snap(), determine whether or not a
161 * full update-side operation has occurred, but do not allow the
162 * (ULONG_MAX / 2) safety-factor/guard-band.
163 */
164 static inline bool rcu_seq_done_exact(unsigned long *sp, unsigned long s)
165 {
166 unsigned long cur_s = READ_ONCE(*sp);
167
168 return ULONG_CMP_GE(cur_s, s) || ULONG_CMP_LT(cur_s, s - (2 * RCU_SEQ_STATE_MASK + 1));
169 }
170
171 /*
172 * Has a grace period completed since the time the old gp_seq was collected?
173 */
174 static inline bool rcu_seq_completed_gp(unsigned long old, unsigned long new)
175 {
176 return ULONG_CMP_LT(old, new & ~RCU_SEQ_STATE_MASK);
177 }
178
179 /*
180 * Has a grace period started since the time the old gp_seq was collected?
181 */
182 static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new)
183 {
184 return ULONG_CMP_LT((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK,
185 new);
186 }
187
188 /*
189 * Roughly how many full grace periods have elapsed between the collection
190 * of the two specified grace periods?
191 */
192 static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old)
193 {
194 unsigned long rnd_diff;
195
196 if (old == new)
197 return 0;
198 /*
199 * Compute the number of grace periods (still shifted up), plus
200 * one if either of new and old is not an exact grace period.
201 */
202 rnd_diff = (new & ~RCU_SEQ_STATE_MASK) -
203 ((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK) +
204 ((new & RCU_SEQ_STATE_MASK) || (old & RCU_SEQ_STATE_MASK));
205 if (ULONG_CMP_GE(RCU_SEQ_STATE_MASK, rnd_diff))
206 return 1; /* Definitely no grace period has elapsed. */
207 return ((rnd_diff - RCU_SEQ_STATE_MASK - 1) >> RCU_SEQ_CTR_SHIFT) + 2;
208 }
209
210 /*
211 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
212 * by call_rcu() and rcu callback execution, and are therefore not part
213 * of the RCU API. These are in rcupdate.h because they are used by all
214 * RCU implementations.
215 */
216
217 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
218 # define STATE_RCU_HEAD_READY 0
219 # define STATE_RCU_HEAD_QUEUED 1
220
221 extern const struct debug_obj_descr rcuhead_debug_descr;
222
223 static inline int debug_rcu_head_queue(struct rcu_head *head)
224 {
225 int r1;
226
227 r1 = debug_object_activate(head, &rcuhead_debug_descr);
228 debug_object_active_state(head, &rcuhead_debug_descr,
229 STATE_RCU_HEAD_READY,
230 STATE_RCU_HEAD_QUEUED);
231 return r1;
232 }
233
234 static inline void debug_rcu_head_unqueue(struct rcu_head *head)
235 {
236 debug_object_active_state(head, &rcuhead_debug_descr,
237 STATE_RCU_HEAD_QUEUED,
238 STATE_RCU_HEAD_READY);
239 debug_object_deactivate(head, &rcuhead_debug_descr);
240 }
241 #else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
242 static inline int debug_rcu_head_queue(struct rcu_head *head)
243 {
244 return 0;
245 }
246
247 static inline void debug_rcu_head_unqueue(struct rcu_head *head)
248 {
249 }
250 #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
251
252 static inline void debug_rcu_head_callback(struct rcu_head *rhp)
253 {
254 if (unlikely(!rhp->func))
255 kmem_dump_obj(rhp);
256 }
257
258 extern int rcu_cpu_stall_suppress_at_boot;
259
260 static inline bool rcu_stall_is_suppressed_at_boot(void)
261 {
262 return rcu_cpu_stall_suppress_at_boot && !rcu_inkernel_boot_has_ended();
263 }
264
265 extern int rcu_cpu_stall_notifiers;
266
267 #ifdef CONFIG_RCU_STALL_COMMON
268
269 extern int rcu_cpu_stall_ftrace_dump;
270 extern int rcu_cpu_stall_suppress;
271 extern int rcu_cpu_stall_timeout;
272 extern int rcu_exp_cpu_stall_timeout;
273 extern int rcu_cpu_stall_cputime;
274 extern bool rcu_exp_stall_task_details __read_mostly;
275 int rcu_jiffies_till_stall_check(void);
276 int rcu_exp_jiffies_till_stall_check(void);
277
278 static inline bool rcu_stall_is_suppressed(void)
279 {
280 return rcu_stall_is_suppressed_at_boot() || rcu_cpu_stall_suppress;
281 }
282
283 #define rcu_ftrace_dump_stall_suppress() \
284 do { \
285 if (!rcu_cpu_stall_suppress) \
286 rcu_cpu_stall_suppress = 3; \
287 } while (0)
288
289 #define rcu_ftrace_dump_stall_unsuppress() \
290 do { \
291 if (rcu_cpu_stall_suppress == 3) \
292 rcu_cpu_stall_suppress = 0; \
293 } while (0)
294
295 #else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
296
297 static inline bool rcu_stall_is_suppressed(void)
298 {
299 return rcu_stall_is_suppressed_at_boot();
300 }
301 #define rcu_ftrace_dump_stall_suppress()
302 #define rcu_ftrace_dump_stall_unsuppress()
303 #endif /* #ifdef CONFIG_RCU_STALL_COMMON */
304
305 /*
306 * Strings used in tracepoints need to be exported via the
307 * tracing system such that tools like perf and trace-cmd can
308 * translate the string address pointers to actual text.
309 */
310 #define TPS(x) tracepoint_string(x)
311
312 /*
313 * Dump the ftrace buffer, but only one time per callsite per boot.
314 */
315 #define rcu_ftrace_dump(oops_dump_mode) \
316 do { \
317 static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
318 \
319 if (!atomic_read(&___rfd_beenhere) && \
320 !atomic_xchg(&___rfd_beenhere, 1)) { \
321 tracing_off(); \
322 rcu_ftrace_dump_stall_suppress(); \
323 ftrace_dump(oops_dump_mode); \
324 rcu_ftrace_dump_stall_unsuppress(); \
325 } \
326 } while (0)
327
328 void rcu_early_boot_tests(void);
329 void rcu_test_sync_prims(void);
330
331 /*
332 * This function really isn't for public consumption, but RCU is special in
333 * that context switches can allow the state machine to make progress.
334 */
335 extern void resched_cpu(int cpu);
336
337 #if !defined(CONFIG_TINY_RCU)
338
339 #include <linux/rcu_node_tree.h>
340
341 extern int rcu_num_lvls;
342 extern int num_rcu_lvl[];
343 extern int rcu_num_nodes;
344 static bool rcu_fanout_exact;
345 static int rcu_fanout_leaf;
346
347 /*
348 * Compute the per-level fanout, either using the exact fanout specified
349 * or balancing the tree, depending on the rcu_fanout_exact boot parameter.
350 */
351 static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
352 {
353 int i;
354
355 for (i = 0; i < RCU_NUM_LVLS; i++)
356 levelspread[i] = INT_MIN;
357 if (rcu_fanout_exact) {
358 levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
359 for (i = rcu_num_lvls - 2; i >= 0; i--)
360 levelspread[i] = RCU_FANOUT;
361 } else {
362 int ccur;
363 int cprv;
364
365 cprv = nr_cpu_ids;
366 for (i = rcu_num_lvls - 1; i >= 0; i--) {
367 ccur = levelcnt[i];
368 levelspread[i] = (cprv + ccur - 1) / ccur;
369 cprv = ccur;
370 }
371 }
372 }
373
374 extern void rcu_init_geometry(void);
375
376 /* Returns a pointer to the first leaf rcu_node structure. */
377 #define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
378
379 /* Is this rcu_node a leaf? */
380 #define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
381
382 /* Is this rcu_node the last leaf? */
383 #define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])
384
385 /*
386 * Do a full breadth-first scan of the {s,}rcu_node structures for the
387 * specified state structure (for SRCU) or the only rcu_state structure
388 * (for RCU).
389 */
390 #define _rcu_for_each_node_breadth_first(sp, rnp) \
391 for ((rnp) = &(sp)->node[0]; \
392 (rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
393 #define rcu_for_each_node_breadth_first(rnp) \
394 _rcu_for_each_node_breadth_first(&rcu_state, rnp)
395 #define srcu_for_each_node_breadth_first(ssp, rnp) \
396 _rcu_for_each_node_breadth_first(ssp->srcu_sup, rnp)
397
398 /*
399 * Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
400 * Note that if there is a singleton rcu_node tree with but one rcu_node
401 * structure, this loop -will- visit the rcu_node structure. It is still
402 * a leaf node, even if it is also the root node.
403 */
404 #define rcu_for_each_leaf_node(rnp) \
405 for ((rnp) = rcu_first_leaf_node(); \
406 (rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)
407
408 /*
409 * Iterate over all possible CPUs in a leaf RCU node.
410 */
411 #define for_each_leaf_node_possible_cpu(rnp, cpu) \
412 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
413 (cpu) = cpumask_next((rnp)->grplo - 1, cpu_possible_mask); \
414 (cpu) <= rnp->grphi; \
415 (cpu) = cpumask_next((cpu), cpu_possible_mask))
416
417 /*
418 * Iterate over all CPUs in a leaf RCU node's specified mask.
419 */
420 #define rcu_find_next_bit(rnp, cpu, mask) \
421 ((rnp)->grplo + find_next_bit(&(mask), BITS_PER_LONG, (cpu)))
422 #define for_each_leaf_node_cpu_mask(rnp, cpu, mask) \
423 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
424 (cpu) = rcu_find_next_bit((rnp), 0, (mask)); \
425 (cpu) <= rnp->grphi; \
426 (cpu) = rcu_find_next_bit((rnp), (cpu) + 1 - (rnp->grplo), (mask)))
427
428 #endif /* !defined(CONFIG_TINY_RCU) */
429
430 #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
431
432 /*
433 * Wrappers for the rcu_node::lock acquire and release.
434 *
435 * Because the rcu_nodes form a tree, the tree traversal locking will observe
436 * different lock values, this in turn means that an UNLOCK of one level
437 * followed by a LOCK of another level does not imply a full memory barrier;
438 * and most importantly transitivity is lost.
439 *
440 * In order to restore full ordering between tree levels, augment the regular
441 * lock acquire functions with smp_mb__after_unlock_lock().
442 *
443 * As ->lock of struct rcu_node is a __private field, therefore one should use
444 * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
445 */
446 #define raw_spin_lock_rcu_node(p) \
447 do { \
448 raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \
449 smp_mb__after_unlock_lock(); \
450 } while (0)
451
452 #define raw_spin_unlock_rcu_node(p) \
453 do { \
454 lockdep_assert_irqs_disabled(); \
455 raw_spin_unlock(&ACCESS_PRIVATE(p, lock)); \
456 } while (0)
457
458 #define raw_spin_lock_irq_rcu_node(p) \
459 do { \
460 raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \
461 smp_mb__after_unlock_lock(); \
462 } while (0)
463
464 #define raw_spin_unlock_irq_rcu_node(p) \
465 do { \
466 lockdep_assert_irqs_disabled(); \
467 raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock)); \
468 } while (0)
469
470 #define raw_spin_lock_irqsave_rcu_node(p, flags) \
471 do { \
472 raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
473 smp_mb__after_unlock_lock(); \
474 } while (0)
475
476 #define raw_spin_unlock_irqrestore_rcu_node(p, flags) \
477 do { \
478 lockdep_assert_irqs_disabled(); \
479 raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags); \
480 } while (0)
481
482 #define raw_spin_trylock_rcu_node(p) \
483 ({ \
484 bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \
485 \
486 if (___locked) \
487 smp_mb__after_unlock_lock(); \
488 ___locked; \
489 })
490
491 #define raw_lockdep_assert_held_rcu_node(p) \
492 lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
493
494 #endif // #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
495
496 #ifdef CONFIG_TINY_RCU
497 /* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
498 static inline bool rcu_gp_is_normal(void) { return true; }
499 static inline bool rcu_gp_is_expedited(void) { return false; }
500 static inline bool rcu_async_should_hurry(void) { return false; }
501 static inline void rcu_expedite_gp(void) { }
502 static inline void rcu_unexpedite_gp(void) { }
503 static inline void rcu_async_hurry(void) { }
504 static inline void rcu_async_relax(void) { }
505 static inline bool rcu_cpu_online(int cpu) { return true; }
506 #else /* #ifdef CONFIG_TINY_RCU */
507 bool rcu_gp_is_normal(void); /* Internal RCU use. */
508 bool rcu_gp_is_expedited(void); /* Internal RCU use. */
509 bool rcu_async_should_hurry(void); /* Internal RCU use. */
510 void rcu_expedite_gp(void);
511 void rcu_unexpedite_gp(void);
512 void rcu_async_hurry(void);
513 void rcu_async_relax(void);
514 void rcupdate_announce_bootup_oddness(void);
515 bool rcu_cpu_online(int cpu);
516 #ifdef CONFIG_TASKS_RCU_GENERIC
517 void show_rcu_tasks_gp_kthreads(void);
518 #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
519 static inline void show_rcu_tasks_gp_kthreads(void) {}
520 #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
521 #endif /* #else #ifdef CONFIG_TINY_RCU */
522
523 #ifdef CONFIG_TASKS_RCU
524 struct task_struct *get_rcu_tasks_gp_kthread(void);
525 void rcu_tasks_get_gp_data(int *flags, unsigned long *gp_seq);
526 #endif // # ifdef CONFIG_TASKS_RCU
527
528 #ifdef CONFIG_TASKS_RUDE_RCU
529 struct task_struct *get_rcu_tasks_rude_gp_kthread(void);
530 void rcu_tasks_rude_get_gp_data(int *flags, unsigned long *gp_seq);
531 #endif // # ifdef CONFIG_TASKS_RUDE_RCU
532
533 #ifdef CONFIG_TASKS_TRACE_RCU
534 void rcu_tasks_trace_get_gp_data(int *flags, unsigned long *gp_seq);
535 #endif
536
537 #ifdef CONFIG_TASKS_RCU_GENERIC
538 void tasks_cblist_init_generic(void);
539 #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
540 static inline void tasks_cblist_init_generic(void) { }
541 #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
542
543 #define RCU_SCHEDULER_INACTIVE 0
544 #define RCU_SCHEDULER_INIT 1
545 #define RCU_SCHEDULER_RUNNING 2
546
547 enum rcutorture_type {
548 RCU_FLAVOR,
549 RCU_TASKS_FLAVOR,
550 RCU_TASKS_RUDE_FLAVOR,
551 RCU_TASKS_TRACING_FLAVOR,
552 RCU_TRIVIAL_FLAVOR,
553 SRCU_FLAVOR,
554 INVALID_RCU_FLAVOR
555 };
556
557 #if defined(CONFIG_RCU_LAZY)
558 unsigned long rcu_get_jiffies_lazy_flush(void);
559 void rcu_set_jiffies_lazy_flush(unsigned long j);
560 #else
561 static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }
562 static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }
563 #endif
564
565 #if defined(CONFIG_TREE_RCU)
566 void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq);
567 void do_trace_rcu_torture_read(const char *rcutorturename,
568 struct rcu_head *rhp,
569 unsigned long secs,
570 unsigned long c_old,
571 unsigned long c);
572 void rcu_gp_set_torture_wait(int duration);
573 #else
574 static inline void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq)
575 {
576 *flags = 0;
577 *gp_seq = 0;
578 }
579 #ifdef CONFIG_RCU_TRACE
580 void do_trace_rcu_torture_read(const char *rcutorturename,
581 struct rcu_head *rhp,
582 unsigned long secs,
583 unsigned long c_old,
584 unsigned long c);
585 #else
586 #define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
587 do { } while (0)
588 #endif
589 static inline void rcu_gp_set_torture_wait(int duration) { }
590 #endif
591
592 #ifdef CONFIG_TINY_SRCU
593
594 static inline void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
595 unsigned long *gp_seq)
596 {
597 *flags = 0;
598 *gp_seq = sp->srcu_idx;
599 }
600
601 #elif defined(CONFIG_TREE_SRCU)
602
603 void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
604 unsigned long *gp_seq);
605
606 #endif
607
608 #ifdef CONFIG_TINY_RCU
609 static inline bool rcu_dynticks_zero_in_eqs(int cpu, int *vp) { return false; }
610 static inline unsigned long rcu_get_gp_seq(void) { return 0; }
611 static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
612 static inline unsigned long
613 srcu_batches_completed(struct srcu_struct *sp) { return 0; }
614 static inline void rcu_force_quiescent_state(void) { }
615 static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
616 static inline void show_rcu_gp_kthreads(void) { }
617 static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
618 static inline void rcu_fwd_progress_check(unsigned long j) { }
619 static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
620 static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
621 #else /* #ifdef CONFIG_TINY_RCU */
622 bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
623 unsigned long rcu_get_gp_seq(void);
624 unsigned long rcu_exp_batches_completed(void);
625 unsigned long srcu_batches_completed(struct srcu_struct *sp);
626 bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
627 void show_rcu_gp_kthreads(void);
628 int rcu_get_gp_kthreads_prio(void);
629 void rcu_fwd_progress_check(unsigned long j);
630 void rcu_force_quiescent_state(void);
631 extern struct workqueue_struct *rcu_gp_wq;
632 extern struct kthread_worker *rcu_exp_gp_kworker;
633 void rcu_gp_slow_register(atomic_t *rgssp);
634 void rcu_gp_slow_unregister(atomic_t *rgssp);
635 #endif /* #else #ifdef CONFIG_TINY_RCU */
636
637 #ifdef CONFIG_RCU_NOCB_CPU
638 void rcu_bind_current_to_nocb(void);
639 #else
640 static inline void rcu_bind_current_to_nocb(void) { }
641 #endif
642
643 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
644 void show_rcu_tasks_classic_gp_kthread(void);
645 #else
646 static inline void show_rcu_tasks_classic_gp_kthread(void) {}
647 #endif
648 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
649 void show_rcu_tasks_rude_gp_kthread(void);
650 #else
651 static inline void show_rcu_tasks_rude_gp_kthread(void) {}
652 #endif
653 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_TRACE_RCU)
654 void show_rcu_tasks_trace_gp_kthread(void);
655 #else
656 static inline void show_rcu_tasks_trace_gp_kthread(void) {}
657 #endif
658
659 #ifdef CONFIG_TINY_RCU
660 static inline bool rcu_cpu_beenfullyonline(int cpu) { return true; }
661 #else
662 bool rcu_cpu_beenfullyonline(int cpu);
663 #endif
664
665 #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
666 int rcu_stall_notifier_call_chain(unsigned long val, void *v);
667 #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
668 static inline int rcu_stall_notifier_call_chain(unsigned long val, void *v) { return NOTIFY_DONE; }
669 #endif // #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
670
671 #endif /* __LINUX_RCU_H */
672
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