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