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/* Low-order bit definition for polled grace-period APIs. */
58#define RCU_GET_STATE_COMPLETED 0x1
59
60/* A complete grace period count */
61#define RCU_SEQ_GP (RCU_SEQ_STATE_MASK + 1)
62
63extern 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 */
69static 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 */
78static 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 */
87static 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. */
94static 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. */
102static 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. */
108static 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 */
126static 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. */
136static 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 */
145static 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 */
154static 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 * The token returned by get_state_synchronize_rcu_full() is based on
165 * rcu_state.gp_seq but it is tested in poll_state_synchronize_rcu_full()
166 * against the root rnp->gp_seq. Since rcu_seq_start() is first called
167 * on rcu_state.gp_seq and only later reflected on the root rnp->gp_seq,
168 * it is possible that rcu_seq_snap(rcu_state.gp_seq) returns 2 full grace
169 * periods ahead of the root rnp->gp_seq. To prevent false-positives with the
170 * full polling API that a wrap around instantly completed the GP, when nothing
171 * like that happened, adjust for the 2 GPs in the ULONG_CMP_LT().
172 */
173static inline bool rcu_seq_done_exact(unsigned long *sp, unsigned long s)
174{
175 unsigned long cur_s = READ_ONCE(*sp);
176
177 return ULONG_CMP_GE(cur_s, s) || ULONG_CMP_LT(cur_s, s - (2 * RCU_SEQ_GP));
178}
179
180/*
181 * Has a grace period completed since the time the old gp_seq was collected?
182 */
183static inline bool rcu_seq_completed_gp(unsigned long old, unsigned long new)
184{
185 return ULONG_CMP_LT(old, new & ~RCU_SEQ_STATE_MASK);
186}
187
188/*
189 * Has a grace period started since the time the old gp_seq was collected?
190 */
191static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new)
192{
193 return ULONG_CMP_LT((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK,
194 new);
195}
196
197/*
198 * Roughly how many full grace periods have elapsed between the collection
199 * of the two specified grace periods?
200 */
201static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old)
202{
203 unsigned long rnd_diff;
204
205 if (old == new)
206 return 0;
207 /*
208 * Compute the number of grace periods (still shifted up), plus
209 * one if either of new and old is not an exact grace period.
210 */
211 rnd_diff = (new & ~RCU_SEQ_STATE_MASK) -
212 ((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK) +
213 ((new & RCU_SEQ_STATE_MASK) || (old & RCU_SEQ_STATE_MASK));
214 if (ULONG_CMP_GE(RCU_SEQ_STATE_MASK, rnd_diff))
215 return 1; /* Definitely no grace period has elapsed. */
216 return ((rnd_diff - RCU_SEQ_STATE_MASK - 1) >> RCU_SEQ_CTR_SHIFT) + 2;
217}
218
219/*
220 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
221 * by call_rcu() and rcu callback execution, and are therefore not part
222 * of the RCU API. These are in rcupdate.h because they are used by all
223 * RCU implementations.
224 */
225
226#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
227# define STATE_RCU_HEAD_READY 0
228# define STATE_RCU_HEAD_QUEUED 1
229
230extern const struct debug_obj_descr rcuhead_debug_descr;
231
232static inline int debug_rcu_head_queue(struct rcu_head *head)
233{
234 int r1;
235
236 r1 = debug_object_activate(addr: head, descr: &rcuhead_debug_descr);
237 debug_object_active_state(addr: head, descr: &rcuhead_debug_descr,
238 STATE_RCU_HEAD_READY,
239 STATE_RCU_HEAD_QUEUED);
240 return r1;
241}
242
243static inline void debug_rcu_head_unqueue(struct rcu_head *head)
244{
245 debug_object_active_state(addr: head, descr: &rcuhead_debug_descr,
246 STATE_RCU_HEAD_QUEUED,
247 STATE_RCU_HEAD_READY);
248 debug_object_deactivate(addr: head, descr: &rcuhead_debug_descr);
249}
250#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
251static inline int debug_rcu_head_queue(struct rcu_head *head)
252{
253 return 0;
254}
255
256static inline void debug_rcu_head_unqueue(struct rcu_head *head)
257{
258}
259#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
260
261static inline void debug_rcu_head_callback(struct rcu_head *rhp)
262{
263 if (unlikely(!rhp->func))
264 kmem_dump_obj(object: rhp);
265}
266
267static inline bool rcu_barrier_cb_is_done(struct rcu_head *rhp)
268{
269 return rhp->next == rhp;
270}
271
272extern int rcu_cpu_stall_suppress_at_boot;
273
274static inline bool rcu_stall_is_suppressed_at_boot(void)
275{
276 return rcu_cpu_stall_suppress_at_boot && !rcu_inkernel_boot_has_ended();
277}
278
279extern int rcu_cpu_stall_notifiers;
280
281#ifdef CONFIG_RCU_STALL_COMMON
282
283extern int rcu_cpu_stall_ftrace_dump;
284extern int rcu_cpu_stall_suppress;
285extern int rcu_cpu_stall_timeout;
286extern int rcu_exp_cpu_stall_timeout;
287extern int rcu_cpu_stall_cputime;
288extern bool rcu_exp_stall_task_details __read_mostly;
289int rcu_jiffies_till_stall_check(void);
290int rcu_exp_jiffies_till_stall_check(void);
291
292static inline bool rcu_stall_is_suppressed(void)
293{
294 return rcu_stall_is_suppressed_at_boot() || rcu_cpu_stall_suppress;
295}
296
297#define rcu_ftrace_dump_stall_suppress() \
298do { \
299 if (!rcu_cpu_stall_suppress) \
300 rcu_cpu_stall_suppress = 3; \
301} while (0)
302
303#define rcu_ftrace_dump_stall_unsuppress() \
304do { \
305 if (rcu_cpu_stall_suppress == 3) \
306 rcu_cpu_stall_suppress = 0; \
307} while (0)
308
309#else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
310
311static inline bool rcu_stall_is_suppressed(void)
312{
313 return rcu_stall_is_suppressed_at_boot();
314}
315#define rcu_ftrace_dump_stall_suppress()
316#define rcu_ftrace_dump_stall_unsuppress()
317#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
318
319/*
320 * Strings used in tracepoints need to be exported via the
321 * tracing system such that tools like perf and trace-cmd can
322 * translate the string address pointers to actual text.
323 */
324#define TPS(x) tracepoint_string(x)
325
326/*
327 * Dump the ftrace buffer, but only one time per callsite per boot.
328 */
329#define rcu_ftrace_dump(oops_dump_mode) \
330do { \
331 static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
332 \
333 if (!atomic_read(&___rfd_beenhere) && \
334 !atomic_xchg(&___rfd_beenhere, 1)) { \
335 tracing_off(); \
336 rcu_ftrace_dump_stall_suppress(); \
337 ftrace_dump(oops_dump_mode); \
338 rcu_ftrace_dump_stall_unsuppress(); \
339 } \
340} while (0)
341
342void rcu_early_boot_tests(void);
343void rcu_test_sync_prims(void);
344
345/*
346 * This function really isn't for public consumption, but RCU is special in
347 * that context switches can allow the state machine to make progress.
348 */
349extern void resched_cpu(int cpu);
350
351#if !defined(CONFIG_TINY_RCU)
352
353#include <linux/rcu_node_tree.h>
354
355extern int rcu_num_lvls;
356extern int num_rcu_lvl[];
357extern int rcu_num_nodes;
358static bool rcu_fanout_exact;
359static int rcu_fanout_leaf;
360
361/*
362 * Compute the per-level fanout, either using the exact fanout specified
363 * or balancing the tree, depending on the rcu_fanout_exact boot parameter.
364 */
365static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
366{
367 int i;
368
369 for (i = 0; i < RCU_NUM_LVLS; i++)
370 levelspread[i] = INT_MIN;
371 if (rcu_fanout_exact) {
372 levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
373 for (i = rcu_num_lvls - 2; i >= 0; i--)
374 levelspread[i] = RCU_FANOUT;
375 } else {
376 int ccur;
377 int cprv;
378
379 cprv = nr_cpu_ids;
380 for (i = rcu_num_lvls - 1; i >= 0; i--) {
381 ccur = levelcnt[i];
382 levelspread[i] = (cprv + ccur - 1) / ccur;
383 cprv = ccur;
384 }
385 }
386}
387
388extern void rcu_init_geometry(void);
389
390/* Returns a pointer to the first leaf rcu_node structure. */
391#define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
392
393/* Is this rcu_node a leaf? */
394#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
395
396/* Is this rcu_node the last leaf? */
397#define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])
398
399/*
400 * Do a full breadth-first scan of the {s,}rcu_node structures for the
401 * specified state structure (for SRCU) or the only rcu_state structure
402 * (for RCU).
403 */
404#define _rcu_for_each_node_breadth_first(sp, rnp) \
405 for ((rnp) = &(sp)->node[0]; \
406 (rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
407#define rcu_for_each_node_breadth_first(rnp) \
408 _rcu_for_each_node_breadth_first(&rcu_state, rnp)
409#define srcu_for_each_node_breadth_first(ssp, rnp) \
410 _rcu_for_each_node_breadth_first(ssp->srcu_sup, rnp)
411
412/*
413 * Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
414 * Note that if there is a singleton rcu_node tree with but one rcu_node
415 * structure, this loop -will- visit the rcu_node structure. It is still
416 * a leaf node, even if it is also the root node.
417 */
418#define rcu_for_each_leaf_node(rnp) \
419 for ((rnp) = rcu_first_leaf_node(); \
420 (rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)
421
422/*
423 * Iterate over all possible CPUs in a leaf RCU node.
424 */
425#define for_each_leaf_node_possible_cpu(rnp, cpu) \
426 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
427 (cpu) = cpumask_next((rnp)->grplo - 1, cpu_possible_mask); \
428 (cpu) <= rnp->grphi; \
429 (cpu) = cpumask_next((cpu), cpu_possible_mask))
430
431/*
432 * Iterate over all CPUs in a leaf RCU node's specified mask.
433 */
434#define rcu_find_next_bit(rnp, cpu, mask) \
435 ((rnp)->grplo + find_next_bit(&(mask), BITS_PER_LONG, (cpu)))
436#define for_each_leaf_node_cpu_mask(rnp, cpu, mask) \
437 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
438 (cpu) = rcu_find_next_bit((rnp), 0, (mask)); \
439 (cpu) <= rnp->grphi; \
440 (cpu) = rcu_find_next_bit((rnp), (cpu) + 1 - (rnp->grplo), (mask)))
441
442#endif /* !defined(CONFIG_TINY_RCU) */
443
444#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
445
446/*
447 * Wrappers for the rcu_node::lock acquire and release.
448 *
449 * Because the rcu_nodes form a tree, the tree traversal locking will observe
450 * different lock values, this in turn means that an UNLOCK of one level
451 * followed by a LOCK of another level does not imply a full memory barrier;
452 * and most importantly transitivity is lost.
453 *
454 * In order to restore full ordering between tree levels, augment the regular
455 * lock acquire functions with smp_mb__after_unlock_lock().
456 *
457 * As ->lock of struct rcu_node is a __private field, therefore one should use
458 * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
459 */
460#define raw_spin_lock_rcu_node(p) \
461do { \
462 raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \
463 smp_mb__after_unlock_lock(); \
464} while (0)
465
466#define raw_spin_unlock_rcu_node(p) \
467do { \
468 lockdep_assert_irqs_disabled(); \
469 raw_spin_unlock(&ACCESS_PRIVATE(p, lock)); \
470} while (0)
471
472#define raw_spin_lock_irq_rcu_node(p) \
473do { \
474 raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \
475 smp_mb__after_unlock_lock(); \
476} while (0)
477
478#define raw_spin_unlock_irq_rcu_node(p) \
479do { \
480 lockdep_assert_irqs_disabled(); \
481 raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock)); \
482} while (0)
483
484#define raw_spin_lock_irqsave_rcu_node(p, flags) \
485do { \
486 raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
487 smp_mb__after_unlock_lock(); \
488} while (0)
489
490#define raw_spin_unlock_irqrestore_rcu_node(p, flags) \
491do { \
492 lockdep_assert_irqs_disabled(); \
493 raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags); \
494} while (0)
495
496#define raw_spin_trylock_rcu_node(p) \
497({ \
498 bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \
499 \
500 if (___locked) \
501 smp_mb__after_unlock_lock(); \
502 ___locked; \
503})
504
505#define raw_lockdep_assert_held_rcu_node(p) \
506 lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
507
508#endif // #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
509
510#ifdef CONFIG_TINY_RCU
511/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
512static inline bool rcu_gp_is_normal(void) { return true; }
513static inline bool rcu_gp_is_expedited(void) { return false; }
514static inline bool rcu_async_should_hurry(void) { return false; }
515static inline void rcu_expedite_gp(void) { }
516static inline void rcu_unexpedite_gp(void) { }
517static inline void rcu_async_hurry(void) { }
518static inline void rcu_async_relax(void) { }
519static inline bool rcu_cpu_online(int cpu) { return true; }
520#else /* #ifdef CONFIG_TINY_RCU */
521bool rcu_gp_is_normal(void); /* Internal RCU use. */
522bool rcu_gp_is_expedited(void); /* Internal RCU use. */
523bool rcu_async_should_hurry(void); /* Internal RCU use. */
524void rcu_expedite_gp(void);
525void rcu_unexpedite_gp(void);
526void rcu_async_hurry(void);
527void rcu_async_relax(void);
528void rcupdate_announce_bootup_oddness(void);
529bool rcu_cpu_online(int cpu);
530#ifdef CONFIG_TASKS_RCU_GENERIC
531void show_rcu_tasks_gp_kthreads(void);
532#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
533static inline void show_rcu_tasks_gp_kthreads(void) {}
534#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
535#endif /* #else #ifdef CONFIG_TINY_RCU */
536
537#ifdef CONFIG_TASKS_RCU
538struct task_struct *get_rcu_tasks_gp_kthread(void);
539void rcu_tasks_get_gp_data(int *flags, unsigned long *gp_seq);
540#endif // # ifdef CONFIG_TASKS_RCU
541
542#ifdef CONFIG_TASKS_RUDE_RCU
543struct task_struct *get_rcu_tasks_rude_gp_kthread(void);
544void rcu_tasks_rude_get_gp_data(int *flags, unsigned long *gp_seq);
545#endif // # ifdef CONFIG_TASKS_RUDE_RCU
546
547#ifdef CONFIG_TASKS_TRACE_RCU
548void rcu_tasks_trace_get_gp_data(int *flags, unsigned long *gp_seq);
549#endif
550
551#ifdef CONFIG_TASKS_RCU_GENERIC
552void tasks_cblist_init_generic(void);
553#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
554static inline void tasks_cblist_init_generic(void) { }
555#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
556
557#define RCU_SCHEDULER_INACTIVE 0
558#define RCU_SCHEDULER_INIT 1
559#define RCU_SCHEDULER_RUNNING 2
560
561enum rcutorture_type {
562 RCU_FLAVOR,
563 RCU_TASKS_FLAVOR,
564 RCU_TASKS_RUDE_FLAVOR,
565 RCU_TASKS_TRACING_FLAVOR,
566 RCU_TRIVIAL_FLAVOR,
567 SRCU_FLAVOR,
568 INVALID_RCU_FLAVOR
569};
570
571#if defined(CONFIG_RCU_LAZY)
572unsigned long rcu_get_jiffies_lazy_flush(void);
573void rcu_set_jiffies_lazy_flush(unsigned long j);
574#else
575static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }
576static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }
577#endif
578
579#if defined(CONFIG_TREE_RCU)
580void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq);
581void do_trace_rcu_torture_read(const char *rcutorturename,
582 struct rcu_head *rhp,
583 unsigned long secs,
584 unsigned long c_old,
585 unsigned long c);
586void rcu_gp_set_torture_wait(int duration);
587void rcu_set_gpwrap_lag(unsigned long lag);
588int rcu_get_gpwrap_count(int cpu);
589#else
590static inline void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq)
591{
592 *flags = 0;
593 *gp_seq = 0;
594}
595#ifdef CONFIG_RCU_TRACE
596void do_trace_rcu_torture_read(const char *rcutorturename,
597 struct rcu_head *rhp,
598 unsigned long secs,
599 unsigned long c_old,
600 unsigned long c);
601#else
602#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
603 do { } while (0)
604#endif
605static inline void rcu_gp_set_torture_wait(int duration) { }
606static inline void rcu_set_gpwrap_lag(unsigned long lag) { }
607static inline int rcu_get_gpwrap_count(int cpu) { return 0; }
608#endif
609unsigned long long rcutorture_gather_gp_seqs(void);
610void rcutorture_format_gp_seqs(unsigned long long seqs, char *cp, size_t len);
611
612#ifdef CONFIG_TINY_SRCU
613
614static inline void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
615 unsigned long *gp_seq)
616{
617 *flags = 0;
618 *gp_seq = sp->srcu_idx;
619}
620
621#elif defined(CONFIG_TREE_SRCU)
622
623void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
624 unsigned long *gp_seq);
625
626#endif
627
628#ifdef CONFIG_TINY_RCU
629static inline bool rcu_watching_zero_in_eqs(int cpu, int *vp) { return false; }
630static inline unsigned long rcu_get_gp_seq(void) { return 0; }
631static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
632static inline void rcu_force_quiescent_state(void) { }
633static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
634static inline void show_rcu_gp_kthreads(void) { }
635static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
636static inline void rcu_fwd_progress_check(unsigned long j) { }
637static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
638static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
639#else /* #ifdef CONFIG_TINY_RCU */
640bool rcu_watching_zero_in_eqs(int cpu, int *vp);
641unsigned long rcu_get_gp_seq(void);
642unsigned long rcu_exp_batches_completed(void);
643bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
644void show_rcu_gp_kthreads(void);
645int rcu_get_gp_kthreads_prio(void);
646void rcu_fwd_progress_check(unsigned long j);
647void rcu_force_quiescent_state(void);
648extern struct workqueue_struct *rcu_gp_wq;
649extern struct kthread_worker *rcu_exp_gp_kworker;
650void rcu_gp_slow_register(atomic_t *rgssp);
651void rcu_gp_slow_unregister(atomic_t *rgssp);
652#endif /* #else #ifdef CONFIG_TINY_RCU */
653
654#ifdef CONFIG_TINY_SRCU
655static inline unsigned long srcu_batches_completed(struct srcu_struct *sp) { return 0; }
656#else // #ifdef CONFIG_TINY_SRCU
657unsigned long srcu_batches_completed(struct srcu_struct *sp);
658#endif // #else // #ifdef CONFIG_TINY_SRCU
659
660#ifdef CONFIG_RCU_NOCB_CPU
661void rcu_bind_current_to_nocb(void);
662#else
663static inline void rcu_bind_current_to_nocb(void) { }
664#endif
665
666#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
667void show_rcu_tasks_classic_gp_kthread(void);
668#else
669static inline void show_rcu_tasks_classic_gp_kthread(void) {}
670#endif
671#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
672void show_rcu_tasks_rude_gp_kthread(void);
673#else
674static inline void show_rcu_tasks_rude_gp_kthread(void) {}
675#endif
676#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_TRACE_RCU)
677void show_rcu_tasks_trace_gp_kthread(void);
678#else
679static inline void show_rcu_tasks_trace_gp_kthread(void) {}
680#endif
681
682#ifdef CONFIG_TINY_RCU
683static inline bool rcu_cpu_beenfullyonline(int cpu) { return true; }
684#else
685bool rcu_cpu_beenfullyonline(int cpu);
686#endif
687
688#if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
689int rcu_stall_notifier_call_chain(unsigned long val, void *v);
690#else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
691static inline int rcu_stall_notifier_call_chain(unsigned long val, void *v) { return NOTIFY_DONE; }
692#endif // #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
693
694#endif /* __LINUX_RCU_H */
695

source code of linux/kernel/rcu/rcu.h