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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/* Low-order bit definition for polled grace-period APIs. */
58#define RCU_GET_STATE_COMPLETED 0x1
59
60extern int sysctl_sched_rt_runtime;
61
62/*
63 * Return the counter portion of a sequence number previously returned
64 * by rcu_seq_snap() or rcu_seq_current().
65 */
66static inline unsigned long rcu_seq_ctr(unsigned long s)
67{
68 return s >> RCU_SEQ_CTR_SHIFT;
69}
70
71/*
72 * Return the state portion of a sequence number previously returned
73 * by rcu_seq_snap() or rcu_seq_current().
74 */
75static inline int rcu_seq_state(unsigned long s)
76{
77 return s & RCU_SEQ_STATE_MASK;
78}
79
80/*
81 * Set the state portion of the pointed-to sequence number.
82 * The caller is responsible for preventing conflicting updates.
83 */
84static inline void rcu_seq_set_state(unsigned long *sp, int newstate)
85{
86 WARN_ON_ONCE(newstate & ~RCU_SEQ_STATE_MASK);
87 WRITE_ONCE(*sp, (*sp & ~RCU_SEQ_STATE_MASK) + newstate);
88}
89
90/* Adjust sequence number for start of update-side operation. */
91static inline void rcu_seq_start(unsigned long *sp)
92{
93 WRITE_ONCE(*sp, *sp + 1);
94 smp_mb(); /* Ensure update-side operation after counter increment. */
95 WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
96}
97
98/* Compute the end-of-grace-period value for the specified sequence number. */
99static inline unsigned long rcu_seq_endval(unsigned long *sp)
100{
101 return (*sp | RCU_SEQ_STATE_MASK) + 1;
102}
103
104/* Adjust sequence number for end of update-side operation. */
105static inline void rcu_seq_end(unsigned long *sp)
106{
107 smp_mb(); /* Ensure update-side operation before counter increment. */
108 WARN_ON_ONCE(!rcu_seq_state(*sp));
109 WRITE_ONCE(*sp, rcu_seq_endval(sp));
110}
111
112/*
113 * rcu_seq_snap - Take a snapshot of the update side's sequence number.
114 *
115 * This function returns the earliest value of the grace-period sequence number
116 * that will indicate that a full grace period has elapsed since the current
117 * time. Once the grace-period sequence number has reached this value, it will
118 * be safe to invoke all callbacks that have been registered prior to the
119 * current time. This value is the current grace-period number plus two to the
120 * power of the number of low-order bits reserved for state, then rounded up to
121 * the next value in which the state bits are all zero.
122 */
123static inline unsigned long rcu_seq_snap(unsigned long *sp)
124{
125 unsigned long s;
126
127 s = (READ_ONCE(*sp) + 2 * RCU_SEQ_STATE_MASK + 1) & ~RCU_SEQ_STATE_MASK;
128 smp_mb(); /* Above access must not bleed into critical section. */
129 return s;
130}
131
132/* Return the current value the update side's sequence number, no ordering. */
133static inline unsigned long rcu_seq_current(unsigned long *sp)
134{
135 return READ_ONCE(*sp);
136}
137
138/*
139 * Given a snapshot from rcu_seq_snap(), determine whether or not the
140 * corresponding update-side operation has started.
141 */
142static inline bool rcu_seq_started(unsigned long *sp, unsigned long s)
143{
144 return ULONG_CMP_LT((s - 1) & ~RCU_SEQ_STATE_MASK, READ_ONCE(*sp));
145}
146
147/*
148 * Given a snapshot from rcu_seq_snap(), determine whether or not a
149 * full update-side operation has occurred.
150 */
151static inline bool rcu_seq_done(unsigned long *sp, unsigned long s)
152{
153 return ULONG_CMP_GE(READ_ONCE(*sp), s);
154}
155
156/*
157 * Given a snapshot from rcu_seq_snap(), determine whether or not a
158 * full update-side operation has occurred, but do not allow the
159 * (ULONG_MAX / 2) safety-factor/guard-band.
160 */
161static inline bool rcu_seq_done_exact(unsigned long *sp, unsigned long s)
162{
163 unsigned long cur_s = READ_ONCE(*sp);
164
165 return ULONG_CMP_GE(cur_s, s) || ULONG_CMP_LT(cur_s, s - (2 * RCU_SEQ_STATE_MASK + 1));
166}
167
168/*
169 * Has a grace period completed since the time the old gp_seq was collected?
170 */
171static inline bool rcu_seq_completed_gp(unsigned long old, unsigned long new)
172{
173 return ULONG_CMP_LT(old, new & ~RCU_SEQ_STATE_MASK);
174}
175
176/*
177 * Has a grace period started since the time the old gp_seq was collected?
178 */
179static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new)
180{
181 return ULONG_CMP_LT((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK,
182 new);
183}
184
185/*
186 * Roughly how many full grace periods have elapsed between the collection
187 * of the two specified grace periods?
188 */
189static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old)
190{
191 unsigned long rnd_diff;
192
193 if (old == new)
194 return 0;
195 /*
196 * Compute the number of grace periods (still shifted up), plus
197 * one if either of new and old is not an exact grace period.
198 */
199 rnd_diff = (new & ~RCU_SEQ_STATE_MASK) -
200 ((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK) +
201 ((new & RCU_SEQ_STATE_MASK) || (old & RCU_SEQ_STATE_MASK));
202 if (ULONG_CMP_GE(RCU_SEQ_STATE_MASK, rnd_diff))
203 return 1; /* Definitely no grace period has elapsed. */
204 return ((rnd_diff - RCU_SEQ_STATE_MASK - 1) >> RCU_SEQ_CTR_SHIFT) + 2;
205}
206
207/*
208 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
209 * by call_rcu() and rcu callback execution, and are therefore not part
210 * of the RCU API. These are in rcupdate.h because they are used by all
211 * RCU implementations.
212 */
213
214#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
215# define STATE_RCU_HEAD_READY 0
216# define STATE_RCU_HEAD_QUEUED 1
217
218extern const struct debug_obj_descr rcuhead_debug_descr;
219
220static inline int debug_rcu_head_queue(struct rcu_head *head)
221{
222 int r1;
223
224 r1 = debug_object_activate(head, &rcuhead_debug_descr);
225 debug_object_active_state(head, &rcuhead_debug_descr,
226 STATE_RCU_HEAD_READY,
227 STATE_RCU_HEAD_QUEUED);
228 return r1;
229}
230
231static inline void debug_rcu_head_unqueue(struct rcu_head *head)
232{
233 debug_object_active_state(head, &rcuhead_debug_descr,
234 STATE_RCU_HEAD_QUEUED,
235 STATE_RCU_HEAD_READY);
236 debug_object_deactivate(head, &rcuhead_debug_descr);
237}
238#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
239static inline int debug_rcu_head_queue(struct rcu_head *head)
240{
241 return 0;
242}
243
244static inline void debug_rcu_head_unqueue(struct rcu_head *head)
245{
246}
247#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
248
249static inline void debug_rcu_head_callback(struct rcu_head *rhp)
250{
251 if (unlikely(!rhp->func))
252 kmem_dump_obj(rhp);
253}
254
255static inline bool rcu_barrier_cb_is_done(struct rcu_head *rhp)
256{
257 return rhp->next == rhp;
258}
259
260extern int rcu_cpu_stall_suppress_at_boot;
261
262static inline bool rcu_stall_is_suppressed_at_boot(void)
263{
264 return rcu_cpu_stall_suppress_at_boot && !rcu_inkernel_boot_has_ended();
265}
266
267extern int rcu_cpu_stall_notifiers;
268
269#ifdef CONFIG_RCU_STALL_COMMON
270
271extern int rcu_cpu_stall_ftrace_dump;
272extern int rcu_cpu_stall_suppress;
273extern int rcu_cpu_stall_timeout;
274extern int rcu_exp_cpu_stall_timeout;
275extern int rcu_cpu_stall_cputime;
276extern bool rcu_exp_stall_task_details __read_mostly;
277int rcu_jiffies_till_stall_check(void);
278int rcu_exp_jiffies_till_stall_check(void);
279
280static inline bool rcu_stall_is_suppressed(void)
281{
282 return rcu_stall_is_suppressed_at_boot() || rcu_cpu_stall_suppress;
283}
284
285#define rcu_ftrace_dump_stall_suppress() \
286do { \
287 if (!rcu_cpu_stall_suppress) \
288 rcu_cpu_stall_suppress = 3; \
289} while (0)
290
291#define rcu_ftrace_dump_stall_unsuppress() \
292do { \
293 if (rcu_cpu_stall_suppress == 3) \
294 rcu_cpu_stall_suppress = 0; \
295} while (0)
296
297#else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
298
299static inline bool rcu_stall_is_suppressed(void)
300{
301 return rcu_stall_is_suppressed_at_boot();
302}
303#define rcu_ftrace_dump_stall_suppress()
304#define rcu_ftrace_dump_stall_unsuppress()
305#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
306
307/*
308 * Strings used in tracepoints need to be exported via the
309 * tracing system such that tools like perf and trace-cmd can
310 * translate the string address pointers to actual text.
311 */
312#define TPS(x) tracepoint_string(x)
313
314/*
315 * Dump the ftrace buffer, but only one time per callsite per boot.
316 */
317#define rcu_ftrace_dump(oops_dump_mode) \
318do { \
319 static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
320 \
321 if (!atomic_read(&___rfd_beenhere) && \
322 !atomic_xchg(&___rfd_beenhere, 1)) { \
323 tracing_off(); \
324 rcu_ftrace_dump_stall_suppress(); \
325 ftrace_dump(oops_dump_mode); \
326 rcu_ftrace_dump_stall_unsuppress(); \
327 } \
328} while (0)
329
330void rcu_early_boot_tests(void);
331void rcu_test_sync_prims(void);
332
333/*
334 * This function really isn't for public consumption, but RCU is special in
335 * that context switches can allow the state machine to make progress.
336 */
337extern void resched_cpu(int cpu);
338
339#if !defined(CONFIG_TINY_RCU)
340
341#include <linux/rcu_node_tree.h>
342
343extern int rcu_num_lvls;
344extern int num_rcu_lvl[];
345extern int rcu_num_nodes;
346static bool rcu_fanout_exact;
347static int rcu_fanout_leaf;
348
349/*
350 * Compute the per-level fanout, either using the exact fanout specified
351 * or balancing the tree, depending on the rcu_fanout_exact boot parameter.
352 */
353static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
354{
355 int i;
356
357 for (i = 0; i < RCU_NUM_LVLS; i++)
358 levelspread[i] = INT_MIN;
359 if (rcu_fanout_exact) {
360 levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
361 for (i = rcu_num_lvls - 2; i >= 0; i--)
362 levelspread[i] = RCU_FANOUT;
363 } else {
364 int ccur;
365 int cprv;
366
367 cprv = nr_cpu_ids;
368 for (i = rcu_num_lvls - 1; i >= 0; i--) {
369 ccur = levelcnt[i];
370 levelspread[i] = (cprv + ccur - 1) / ccur;
371 cprv = ccur;
372 }
373 }
374}
375
376extern void rcu_init_geometry(void);
377
378/* Returns a pointer to the first leaf rcu_node structure. */
379#define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
380
381/* Is this rcu_node a leaf? */
382#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
383
384/* Is this rcu_node the last leaf? */
385#define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])
386
387/*
388 * Do a full breadth-first scan of the {s,}rcu_node structures for the
389 * specified state structure (for SRCU) or the only rcu_state structure
390 * (for RCU).
391 */
392#define _rcu_for_each_node_breadth_first(sp, rnp) \
393 for ((rnp) = &(sp)->node[0]; \
394 (rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
395#define rcu_for_each_node_breadth_first(rnp) \
396 _rcu_for_each_node_breadth_first(&rcu_state, rnp)
397#define srcu_for_each_node_breadth_first(ssp, rnp) \
398 _rcu_for_each_node_breadth_first(ssp->srcu_sup, rnp)
399
400/*
401 * Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
402 * Note that if there is a singleton rcu_node tree with but one rcu_node
403 * structure, this loop -will- visit the rcu_node structure. It is still
404 * a leaf node, even if it is also the root node.
405 */
406#define rcu_for_each_leaf_node(rnp) \
407 for ((rnp) = rcu_first_leaf_node(); \
408 (rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)
409
410/*
411 * Iterate over all possible CPUs in a leaf RCU node.
412 */
413#define for_each_leaf_node_possible_cpu(rnp, cpu) \
414 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
415 (cpu) = cpumask_next((rnp)->grplo - 1, cpu_possible_mask); \
416 (cpu) <= rnp->grphi; \
417 (cpu) = cpumask_next((cpu), cpu_possible_mask))
418
419/*
420 * Iterate over all CPUs in a leaf RCU node's specified mask.
421 */
422#define rcu_find_next_bit(rnp, cpu, mask) \
423 ((rnp)->grplo + find_next_bit(&(mask), BITS_PER_LONG, (cpu)))
424#define for_each_leaf_node_cpu_mask(rnp, cpu, mask) \
425 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
426 (cpu) = rcu_find_next_bit((rnp), 0, (mask)); \
427 (cpu) <= rnp->grphi; \
428 (cpu) = rcu_find_next_bit((rnp), (cpu) + 1 - (rnp->grplo), (mask)))
429
430#endif /* !defined(CONFIG_TINY_RCU) */
431
432#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
433
434/*
435 * Wrappers for the rcu_node::lock acquire and release.
436 *
437 * Because the rcu_nodes form a tree, the tree traversal locking will observe
438 * different lock values, this in turn means that an UNLOCK of one level
439 * followed by a LOCK of another level does not imply a full memory barrier;
440 * and most importantly transitivity is lost.
441 *
442 * In order to restore full ordering between tree levels, augment the regular
443 * lock acquire functions with smp_mb__after_unlock_lock().
444 *
445 * As ->lock of struct rcu_node is a __private field, therefore one should use
446 * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
447 */
448#define raw_spin_lock_rcu_node(p) \
449do { \
450 raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \
451 smp_mb__after_unlock_lock(); \
452} while (0)
453
454#define raw_spin_unlock_rcu_node(p) \
455do { \
456 lockdep_assert_irqs_disabled(); \
457 raw_spin_unlock(&ACCESS_PRIVATE(p, lock)); \
458} while (0)
459
460#define raw_spin_lock_irq_rcu_node(p) \
461do { \
462 raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \
463 smp_mb__after_unlock_lock(); \
464} while (0)
465
466#define raw_spin_unlock_irq_rcu_node(p) \
467do { \
468 lockdep_assert_irqs_disabled(); \
469 raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock)); \
470} while (0)
471
472#define raw_spin_lock_irqsave_rcu_node(p, flags) \
473do { \
474 raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
475 smp_mb__after_unlock_lock(); \
476} while (0)
477
478#define raw_spin_unlock_irqrestore_rcu_node(p, flags) \
479do { \
480 lockdep_assert_irqs_disabled(); \
481 raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags); \
482} while (0)
483
484#define raw_spin_trylock_rcu_node(p) \
485({ \
486 bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \
487 \
488 if (___locked) \
489 smp_mb__after_unlock_lock(); \
490 ___locked; \
491})
492
493#define raw_lockdep_assert_held_rcu_node(p) \
494 lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
495
496#endif // #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
497
498#ifdef CONFIG_TINY_RCU
499/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
500static inline bool rcu_gp_is_normal(void) { return true; }
501static inline bool rcu_gp_is_expedited(void) { return false; }
502static inline bool rcu_async_should_hurry(void) { return false; }
503static inline void rcu_expedite_gp(void) { }
504static inline void rcu_unexpedite_gp(void) { }
505static inline void rcu_async_hurry(void) { }
506static inline void rcu_async_relax(void) { }
507static inline bool rcu_cpu_online(int cpu) { return true; }
508#else /* #ifdef CONFIG_TINY_RCU */
509bool rcu_gp_is_normal(void); /* Internal RCU use. */
510bool rcu_gp_is_expedited(void); /* Internal RCU use. */
511bool rcu_async_should_hurry(void); /* Internal RCU use. */
512void rcu_expedite_gp(void);
513void rcu_unexpedite_gp(void);
514void rcu_async_hurry(void);
515void rcu_async_relax(void);
516void rcupdate_announce_bootup_oddness(void);
517bool rcu_cpu_online(int cpu);
518#ifdef CONFIG_TASKS_RCU_GENERIC
519void show_rcu_tasks_gp_kthreads(void);
520#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
521static inline void show_rcu_tasks_gp_kthreads(void) {}
522#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
523#endif /* #else #ifdef CONFIG_TINY_RCU */
524
525#ifdef CONFIG_TASKS_RCU
526struct task_struct *get_rcu_tasks_gp_kthread(void);
527void rcu_tasks_get_gp_data(int *flags, unsigned long *gp_seq);
528#endif // # ifdef CONFIG_TASKS_RCU
529
530#ifdef CONFIG_TASKS_RUDE_RCU
531struct task_struct *get_rcu_tasks_rude_gp_kthread(void);
532void rcu_tasks_rude_get_gp_data(int *flags, unsigned long *gp_seq);
533#endif // # ifdef CONFIG_TASKS_RUDE_RCU
534
535#ifdef CONFIG_TASKS_TRACE_RCU
536void rcu_tasks_trace_get_gp_data(int *flags, unsigned long *gp_seq);
537#endif
538
539#ifdef CONFIG_TASKS_RCU_GENERIC
540void tasks_cblist_init_generic(void);
541#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
542static inline void tasks_cblist_init_generic(void) { }
543#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
544
545#define RCU_SCHEDULER_INACTIVE 0
546#define RCU_SCHEDULER_INIT 1
547#define RCU_SCHEDULER_RUNNING 2
548
549enum rcutorture_type {
550 RCU_FLAVOR,
551 RCU_TASKS_FLAVOR,
552 RCU_TASKS_RUDE_FLAVOR,
553 RCU_TASKS_TRACING_FLAVOR,
554 RCU_TRIVIAL_FLAVOR,
555 SRCU_FLAVOR,
556 INVALID_RCU_FLAVOR
557};
558
559#if defined(CONFIG_RCU_LAZY)
560unsigned long rcu_get_jiffies_lazy_flush(void);
561void rcu_set_jiffies_lazy_flush(unsigned long j);
562#else
563static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }
564static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }
565#endif
566
567#if defined(CONFIG_TREE_RCU)
568void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq);
569void do_trace_rcu_torture_read(const char *rcutorturename,
570 struct rcu_head *rhp,
571 unsigned long secs,
572 unsigned long c_old,
573 unsigned long c);
574void rcu_gp_set_torture_wait(int duration);
575#else
576static inline void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq)
577{
578 *flags = 0;
579 *gp_seq = 0;
580}
581#ifdef CONFIG_RCU_TRACE
582void do_trace_rcu_torture_read(const char *rcutorturename,
583 struct rcu_head *rhp,
584 unsigned long secs,
585 unsigned long c_old,
586 unsigned long c);
587#else
588#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
589 do { } while (0)
590#endif
591static inline void rcu_gp_set_torture_wait(int duration) { }
592#endif
593
594#ifdef CONFIG_TINY_SRCU
595
596static inline void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
597 unsigned long *gp_seq)
598{
599 *flags = 0;
600 *gp_seq = sp->srcu_idx;
601}
602
603#elif defined(CONFIG_TREE_SRCU)
604
605void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
606 unsigned long *gp_seq);
607
608#endif
609
610#ifdef CONFIG_TINY_RCU
611static inline bool rcu_watching_zero_in_eqs(int cpu, int *vp) { return false; }
612static inline unsigned long rcu_get_gp_seq(void) { return 0; }
613static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
614static inline unsigned long
615srcu_batches_completed(struct srcu_struct *sp) { return 0; }
616static inline void rcu_force_quiescent_state(void) { }
617static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
618static inline void show_rcu_gp_kthreads(void) { }
619static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
620static inline void rcu_fwd_progress_check(unsigned long j) { }
621static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
622static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
623#else /* #ifdef CONFIG_TINY_RCU */
624bool rcu_watching_zero_in_eqs(int cpu, int *vp);
625unsigned long rcu_get_gp_seq(void);
626unsigned long rcu_exp_batches_completed(void);
627unsigned long srcu_batches_completed(struct srcu_struct *sp);
628bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
629void show_rcu_gp_kthreads(void);
630int rcu_get_gp_kthreads_prio(void);
631void rcu_fwd_progress_check(unsigned long j);
632void rcu_force_quiescent_state(void);
633extern struct workqueue_struct *rcu_gp_wq;
634extern struct kthread_worker *rcu_exp_gp_kworker;
635void rcu_gp_slow_register(atomic_t *rgssp);
636void rcu_gp_slow_unregister(atomic_t *rgssp);
637#endif /* #else #ifdef CONFIG_TINY_RCU */
638
639#ifdef CONFIG_RCU_NOCB_CPU
640void rcu_bind_current_to_nocb(void);
641#else
642static inline void rcu_bind_current_to_nocb(void) { }
643#endif
644
645#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
646void show_rcu_tasks_classic_gp_kthread(void);
647#else
648static inline void show_rcu_tasks_classic_gp_kthread(void) {}
649#endif
650#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
651void show_rcu_tasks_rude_gp_kthread(void);
652#else
653static inline void show_rcu_tasks_rude_gp_kthread(void) {}
654#endif
655#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_TRACE_RCU)
656void show_rcu_tasks_trace_gp_kthread(void);
657#else
658static inline void show_rcu_tasks_trace_gp_kthread(void) {}
659#endif
660
661#ifdef CONFIG_TINY_RCU
662static inline bool rcu_cpu_beenfullyonline(int cpu) { return true; }
663#else
664bool rcu_cpu_beenfullyonline(int cpu);
665#endif
666
667#if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
668int rcu_stall_notifier_call_chain(unsigned long val, void *v);
669#else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
670static inline int rcu_stall_notifier_call_chain(unsigned long val, void *v) { return NOTIFY_DONE; }
671#endif // #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
672
673#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/*
16 * Grace-period counter management.
17 */
18
19#define RCU_SEQ_CTR_SHIFT 2
20#define RCU_SEQ_STATE_MASK ((1 << RCU_SEQ_CTR_SHIFT) - 1)
21
22/* Low-order bit definition for polled grace-period APIs. */
23#define RCU_GET_STATE_COMPLETED 0x1
24
25extern int sysctl_sched_rt_runtime;
26
27/*
28 * Return the counter portion of a sequence number previously returned
29 * by rcu_seq_snap() or rcu_seq_current().
30 */
31static inline unsigned long rcu_seq_ctr(unsigned long s)
32{
33 return s >> RCU_SEQ_CTR_SHIFT;
34}
35
36/*
37 * Return the state portion of a sequence number previously returned
38 * by rcu_seq_snap() or rcu_seq_current().
39 */
40static inline int rcu_seq_state(unsigned long s)
41{
42 return s & RCU_SEQ_STATE_MASK;
43}
44
45/*
46 * Set the state portion of the pointed-to sequence number.
47 * The caller is responsible for preventing conflicting updates.
48 */
49static inline void rcu_seq_set_state(unsigned long *sp, int newstate)
50{
51 WARN_ON_ONCE(newstate & ~RCU_SEQ_STATE_MASK);
52 WRITE_ONCE(*sp, (*sp & ~RCU_SEQ_STATE_MASK) + newstate);
53}
54
55/* Adjust sequence number for start of update-side operation. */
56static inline void rcu_seq_start(unsigned long *sp)
57{
58 WRITE_ONCE(*sp, *sp + 1);
59 smp_mb(); /* Ensure update-side operation after counter increment. */
60 WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
61}
62
63/* Compute the end-of-grace-period value for the specified sequence number. */
64static inline unsigned long rcu_seq_endval(unsigned long *sp)
65{
66 return (*sp | RCU_SEQ_STATE_MASK) + 1;
67}
68
69/* Adjust sequence number for end of update-side operation. */
70static inline void rcu_seq_end(unsigned long *sp)
71{
72 smp_mb(); /* Ensure update-side operation before counter increment. */
73 WARN_ON_ONCE(!rcu_seq_state(*sp));
74 WRITE_ONCE(*sp, rcu_seq_endval(sp));
75}
76
77/*
78 * rcu_seq_snap - Take a snapshot of the update side's sequence number.
79 *
80 * This function returns the earliest value of the grace-period sequence number
81 * that will indicate that a full grace period has elapsed since the current
82 * time. Once the grace-period sequence number has reached this value, it will
83 * be safe to invoke all callbacks that have been registered prior to the
84 * current time. This value is the current grace-period number plus two to the
85 * power of the number of low-order bits reserved for state, then rounded up to
86 * the next value in which the state bits are all zero.
87 */
88static inline unsigned long rcu_seq_snap(unsigned long *sp)
89{
90 unsigned long s;
91
92 s = (READ_ONCE(*sp) + 2 * RCU_SEQ_STATE_MASK + 1) & ~RCU_SEQ_STATE_MASK;
93 smp_mb(); /* Above access must not bleed into critical section. */
94 return s;
95}
96
97/* Return the current value the update side's sequence number, no ordering. */
98static inline unsigned long rcu_seq_current(unsigned long *sp)
99{
100 return READ_ONCE(*sp);
101}
102
103/*
104 * Given a snapshot from rcu_seq_snap(), determine whether or not the
105 * corresponding update-side operation has started.
106 */
107static inline bool rcu_seq_started(unsigned long *sp, unsigned long s)
108{
109 return ULONG_CMP_LT((s - 1) & ~RCU_SEQ_STATE_MASK, READ_ONCE(*sp));
110}
111
112/*
113 * Given a snapshot from rcu_seq_snap(), determine whether or not a
114 * full update-side operation has occurred.
115 */
116static inline bool rcu_seq_done(unsigned long *sp, unsigned long s)
117{
118 return ULONG_CMP_GE(READ_ONCE(*sp), s);
119}
120
121/*
122 * Given a snapshot from rcu_seq_snap(), determine whether or not a
123 * full update-side operation has occurred, but do not allow the
124 * (ULONG_MAX / 2) safety-factor/guard-band.
125 */
126static inline bool rcu_seq_done_exact(unsigned long *sp, unsigned long s)
127{
128 unsigned long cur_s = READ_ONCE(*sp);
129
130 return ULONG_CMP_GE(cur_s, s) || ULONG_CMP_LT(cur_s, s - (2 * RCU_SEQ_STATE_MASK + 1));
131}
132
133/*
134 * Has a grace period completed since the time the old gp_seq was collected?
135 */
136static inline bool rcu_seq_completed_gp(unsigned long old, unsigned long new)
137{
138 return ULONG_CMP_LT(old, new & ~RCU_SEQ_STATE_MASK);
139}
140
141/*
142 * Has a grace period started since the time the old gp_seq was collected?
143 */
144static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new)
145{
146 return ULONG_CMP_LT((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK,
147 new);
148}
149
150/*
151 * Roughly how many full grace periods have elapsed between the collection
152 * of the two specified grace periods?
153 */
154static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old)
155{
156 unsigned long rnd_diff;
157
158 if (old == new)
159 return 0;
160 /*
161 * Compute the number of grace periods (still shifted up), plus
162 * one if either of new and old is not an exact grace period.
163 */
164 rnd_diff = (new & ~RCU_SEQ_STATE_MASK) -
165 ((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK) +
166 ((new & RCU_SEQ_STATE_MASK) || (old & RCU_SEQ_STATE_MASK));
167 if (ULONG_CMP_GE(RCU_SEQ_STATE_MASK, rnd_diff))
168 return 1; /* Definitely no grace period has elapsed. */
169 return ((rnd_diff - RCU_SEQ_STATE_MASK - 1) >> RCU_SEQ_CTR_SHIFT) + 2;
170}
171
172/*
173 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
174 * by call_rcu() and rcu callback execution, and are therefore not part
175 * of the RCU API. These are in rcupdate.h because they are used by all
176 * RCU implementations.
177 */
178
179#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
180# define STATE_RCU_HEAD_READY 0
181# define STATE_RCU_HEAD_QUEUED 1
182
183extern const struct debug_obj_descr rcuhead_debug_descr;
184
185static inline int debug_rcu_head_queue(struct rcu_head *head)
186{
187 int r1;
188
189 r1 = debug_object_activate(head, &rcuhead_debug_descr);
190 debug_object_active_state(head, &rcuhead_debug_descr,
191 STATE_RCU_HEAD_READY,
192 STATE_RCU_HEAD_QUEUED);
193 return r1;
194}
195
196static inline void debug_rcu_head_unqueue(struct rcu_head *head)
197{
198 debug_object_active_state(head, &rcuhead_debug_descr,
199 STATE_RCU_HEAD_QUEUED,
200 STATE_RCU_HEAD_READY);
201 debug_object_deactivate(head, &rcuhead_debug_descr);
202}
203#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
204static inline int debug_rcu_head_queue(struct rcu_head *head)
205{
206 return 0;
207}
208
209static inline void debug_rcu_head_unqueue(struct rcu_head *head)
210{
211}
212#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
213
214extern int rcu_cpu_stall_suppress_at_boot;
215
216static inline bool rcu_stall_is_suppressed_at_boot(void)
217{
218 return rcu_cpu_stall_suppress_at_boot && !rcu_inkernel_boot_has_ended();
219}
220
221#ifdef CONFIG_RCU_STALL_COMMON
222
223extern int rcu_cpu_stall_ftrace_dump;
224extern int rcu_cpu_stall_suppress;
225extern int rcu_cpu_stall_timeout;
226extern int rcu_exp_cpu_stall_timeout;
227int rcu_jiffies_till_stall_check(void);
228int rcu_exp_jiffies_till_stall_check(void);
229
230static inline bool rcu_stall_is_suppressed(void)
231{
232 return rcu_stall_is_suppressed_at_boot() || rcu_cpu_stall_suppress;
233}
234
235#define rcu_ftrace_dump_stall_suppress() \
236do { \
237 if (!rcu_cpu_stall_suppress) \
238 rcu_cpu_stall_suppress = 3; \
239} while (0)
240
241#define rcu_ftrace_dump_stall_unsuppress() \
242do { \
243 if (rcu_cpu_stall_suppress == 3) \
244 rcu_cpu_stall_suppress = 0; \
245} while (0)
246
247#else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
248
249static inline bool rcu_stall_is_suppressed(void)
250{
251 return rcu_stall_is_suppressed_at_boot();
252}
253#define rcu_ftrace_dump_stall_suppress()
254#define rcu_ftrace_dump_stall_unsuppress()
255#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
256
257/*
258 * Strings used in tracepoints need to be exported via the
259 * tracing system such that tools like perf and trace-cmd can
260 * translate the string address pointers to actual text.
261 */
262#define TPS(x) tracepoint_string(x)
263
264/*
265 * Dump the ftrace buffer, but only one time per callsite per boot.
266 */
267#define rcu_ftrace_dump(oops_dump_mode) \
268do { \
269 static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
270 \
271 if (!atomic_read(&___rfd_beenhere) && \
272 !atomic_xchg(&___rfd_beenhere, 1)) { \
273 tracing_off(); \
274 rcu_ftrace_dump_stall_suppress(); \
275 ftrace_dump(oops_dump_mode); \
276 rcu_ftrace_dump_stall_unsuppress(); \
277 } \
278} while (0)
279
280void rcu_early_boot_tests(void);
281void rcu_test_sync_prims(void);
282
283/*
284 * This function really isn't for public consumption, but RCU is special in
285 * that context switches can allow the state machine to make progress.
286 */
287extern void resched_cpu(int cpu);
288
289#if !defined(CONFIG_TINY_RCU)
290
291#include <linux/rcu_node_tree.h>
292
293extern int rcu_num_lvls;
294extern int num_rcu_lvl[];
295extern int rcu_num_nodes;
296static bool rcu_fanout_exact;
297static int rcu_fanout_leaf;
298
299/*
300 * Compute the per-level fanout, either using the exact fanout specified
301 * or balancing the tree, depending on the rcu_fanout_exact boot parameter.
302 */
303static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
304{
305 int i;
306
307 for (i = 0; i < RCU_NUM_LVLS; i++)
308 levelspread[i] = INT_MIN;
309 if (rcu_fanout_exact) {
310 levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
311 for (i = rcu_num_lvls - 2; i >= 0; i--)
312 levelspread[i] = RCU_FANOUT;
313 } else {
314 int ccur;
315 int cprv;
316
317 cprv = nr_cpu_ids;
318 for (i = rcu_num_lvls - 1; i >= 0; i--) {
319 ccur = levelcnt[i];
320 levelspread[i] = (cprv + ccur - 1) / ccur;
321 cprv = ccur;
322 }
323 }
324}
325
326extern void rcu_init_geometry(void);
327
328/* Returns a pointer to the first leaf rcu_node structure. */
329#define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
330
331/* Is this rcu_node a leaf? */
332#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
333
334/* Is this rcu_node the last leaf? */
335#define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])
336
337/*
338 * Do a full breadth-first scan of the {s,}rcu_node structures for the
339 * specified state structure (for SRCU) or the only rcu_state structure
340 * (for RCU).
341 */
342#define srcu_for_each_node_breadth_first(sp, rnp) \
343 for ((rnp) = &(sp)->node[0]; \
344 (rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
345#define rcu_for_each_node_breadth_first(rnp) \
346 srcu_for_each_node_breadth_first(&rcu_state, rnp)
347
348/*
349 * Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
350 * Note that if there is a singleton rcu_node tree with but one rcu_node
351 * structure, this loop -will- visit the rcu_node structure. It is still
352 * a leaf node, even if it is also the root node.
353 */
354#define rcu_for_each_leaf_node(rnp) \
355 for ((rnp) = rcu_first_leaf_node(); \
356 (rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)
357
358/*
359 * Iterate over all possible CPUs in a leaf RCU node.
360 */
361#define for_each_leaf_node_possible_cpu(rnp, cpu) \
362 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
363 (cpu) = cpumask_next((rnp)->grplo - 1, cpu_possible_mask); \
364 (cpu) <= rnp->grphi; \
365 (cpu) = cpumask_next((cpu), cpu_possible_mask))
366
367/*
368 * Iterate over all CPUs in a leaf RCU node's specified mask.
369 */
370#define rcu_find_next_bit(rnp, cpu, mask) \
371 ((rnp)->grplo + find_next_bit(&(mask), BITS_PER_LONG, (cpu)))
372#define for_each_leaf_node_cpu_mask(rnp, cpu, mask) \
373 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
374 (cpu) = rcu_find_next_bit((rnp), 0, (mask)); \
375 (cpu) <= rnp->grphi; \
376 (cpu) = rcu_find_next_bit((rnp), (cpu) + 1 - (rnp->grplo), (mask)))
377
378#endif /* !defined(CONFIG_TINY_RCU) */
379
380#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
381
382/*
383 * Wrappers for the rcu_node::lock acquire and release.
384 *
385 * Because the rcu_nodes form a tree, the tree traversal locking will observe
386 * different lock values, this in turn means that an UNLOCK of one level
387 * followed by a LOCK of another level does not imply a full memory barrier;
388 * and most importantly transitivity is lost.
389 *
390 * In order to restore full ordering between tree levels, augment the regular
391 * lock acquire functions with smp_mb__after_unlock_lock().
392 *
393 * As ->lock of struct rcu_node is a __private field, therefore one should use
394 * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
395 */
396#define raw_spin_lock_rcu_node(p) \
397do { \
398 raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \
399 smp_mb__after_unlock_lock(); \
400} while (0)
401
402#define raw_spin_unlock_rcu_node(p) \
403do { \
404 lockdep_assert_irqs_disabled(); \
405 raw_spin_unlock(&ACCESS_PRIVATE(p, lock)); \
406} while (0)
407
408#define raw_spin_lock_irq_rcu_node(p) \
409do { \
410 raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \
411 smp_mb__after_unlock_lock(); \
412} while (0)
413
414#define raw_spin_unlock_irq_rcu_node(p) \
415do { \
416 lockdep_assert_irqs_disabled(); \
417 raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock)); \
418} while (0)
419
420#define raw_spin_lock_irqsave_rcu_node(p, flags) \
421do { \
422 raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
423 smp_mb__after_unlock_lock(); \
424} while (0)
425
426#define raw_spin_unlock_irqrestore_rcu_node(p, flags) \
427do { \
428 lockdep_assert_irqs_disabled(); \
429 raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags); \
430} while (0)
431
432#define raw_spin_trylock_rcu_node(p) \
433({ \
434 bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \
435 \
436 if (___locked) \
437 smp_mb__after_unlock_lock(); \
438 ___locked; \
439})
440
441#define raw_lockdep_assert_held_rcu_node(p) \
442 lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
443
444#endif // #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
445
446#ifdef CONFIG_TINY_RCU
447/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
448static inline bool rcu_gp_is_normal(void) { return true; }
449static inline bool rcu_gp_is_expedited(void) { return false; }
450static inline void rcu_expedite_gp(void) { }
451static inline void rcu_unexpedite_gp(void) { }
452static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
453#else /* #ifdef CONFIG_TINY_RCU */
454bool rcu_gp_is_normal(void); /* Internal RCU use. */
455bool rcu_gp_is_expedited(void); /* Internal RCU use. */
456void rcu_expedite_gp(void);
457void rcu_unexpedite_gp(void);
458void rcupdate_announce_bootup_oddness(void);
459#ifdef CONFIG_TASKS_RCU_GENERIC
460void show_rcu_tasks_gp_kthreads(void);
461#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
462static inline void show_rcu_tasks_gp_kthreads(void) {}
463#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
464void rcu_request_urgent_qs_task(struct task_struct *t);
465#endif /* #else #ifdef CONFIG_TINY_RCU */
466
467#define RCU_SCHEDULER_INACTIVE 0
468#define RCU_SCHEDULER_INIT 1
469#define RCU_SCHEDULER_RUNNING 2
470
471enum rcutorture_type {
472 RCU_FLAVOR,
473 RCU_TASKS_FLAVOR,
474 RCU_TASKS_RUDE_FLAVOR,
475 RCU_TASKS_TRACING_FLAVOR,
476 RCU_TRIVIAL_FLAVOR,
477 SRCU_FLAVOR,
478 INVALID_RCU_FLAVOR
479};
480
481#if defined(CONFIG_RCU_LAZY)
482unsigned long rcu_lazy_get_jiffies_till_flush(void);
483void rcu_lazy_set_jiffies_till_flush(unsigned long j);
484#else
485static inline unsigned long rcu_lazy_get_jiffies_till_flush(void) { return 0; }
486static inline void rcu_lazy_set_jiffies_till_flush(unsigned long j) { }
487#endif
488
489#if defined(CONFIG_TREE_RCU)
490void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
491 unsigned long *gp_seq);
492void do_trace_rcu_torture_read(const char *rcutorturename,
493 struct rcu_head *rhp,
494 unsigned long secs,
495 unsigned long c_old,
496 unsigned long c);
497void rcu_gp_set_torture_wait(int duration);
498#else
499static inline void rcutorture_get_gp_data(enum rcutorture_type test_type,
500 int *flags, unsigned long *gp_seq)
501{
502 *flags = 0;
503 *gp_seq = 0;
504}
505#ifdef CONFIG_RCU_TRACE
506void do_trace_rcu_torture_read(const char *rcutorturename,
507 struct rcu_head *rhp,
508 unsigned long secs,
509 unsigned long c_old,
510 unsigned long c);
511#else
512#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
513 do { } while (0)
514#endif
515static inline void rcu_gp_set_torture_wait(int duration) { }
516#endif
517
518#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST)
519long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask);
520#endif
521
522#ifdef CONFIG_TINY_SRCU
523
524static inline void srcutorture_get_gp_data(enum rcutorture_type test_type,
525 struct srcu_struct *sp, int *flags,
526 unsigned long *gp_seq)
527{
528 if (test_type != SRCU_FLAVOR)
529 return;
530 *flags = 0;
531 *gp_seq = sp->srcu_idx;
532}
533
534#elif defined(CONFIG_TREE_SRCU)
535
536void srcutorture_get_gp_data(enum rcutorture_type test_type,
537 struct srcu_struct *sp, int *flags,
538 unsigned long *gp_seq);
539
540#endif
541
542#ifdef CONFIG_TINY_RCU
543static inline bool rcu_dynticks_zero_in_eqs(int cpu, int *vp) { return false; }
544static inline unsigned long rcu_get_gp_seq(void) { return 0; }
545static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
546static inline unsigned long
547srcu_batches_completed(struct srcu_struct *sp) { return 0; }
548static inline void rcu_force_quiescent_state(void) { }
549static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
550static inline void show_rcu_gp_kthreads(void) { }
551static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
552static inline void rcu_fwd_progress_check(unsigned long j) { }
553static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
554static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
555#else /* #ifdef CONFIG_TINY_RCU */
556bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
557unsigned long rcu_get_gp_seq(void);
558unsigned long rcu_exp_batches_completed(void);
559unsigned long srcu_batches_completed(struct srcu_struct *sp);
560bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
561void show_rcu_gp_kthreads(void);
562int rcu_get_gp_kthreads_prio(void);
563void rcu_fwd_progress_check(unsigned long j);
564void rcu_force_quiescent_state(void);
565extern struct workqueue_struct *rcu_gp_wq;
566#ifdef CONFIG_RCU_EXP_KTHREAD
567extern struct kthread_worker *rcu_exp_gp_kworker;
568extern struct kthread_worker *rcu_exp_par_gp_kworker;
569#else /* !CONFIG_RCU_EXP_KTHREAD */
570extern struct workqueue_struct *rcu_par_gp_wq;
571#endif /* CONFIG_RCU_EXP_KTHREAD */
572void rcu_gp_slow_register(atomic_t *rgssp);
573void rcu_gp_slow_unregister(atomic_t *rgssp);
574#endif /* #else #ifdef CONFIG_TINY_RCU */
575
576#ifdef CONFIG_RCU_NOCB_CPU
577void rcu_bind_current_to_nocb(void);
578#else
579static inline void rcu_bind_current_to_nocb(void) { }
580#endif
581
582#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
583void show_rcu_tasks_classic_gp_kthread(void);
584#else
585static inline void show_rcu_tasks_classic_gp_kthread(void) {}
586#endif
587#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
588void show_rcu_tasks_rude_gp_kthread(void);
589#else
590static inline void show_rcu_tasks_rude_gp_kthread(void) {}
591#endif
592#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_TRACE_RCU)
593void show_rcu_tasks_trace_gp_kthread(void);
594#else
595static inline void show_rcu_tasks_trace_gp_kthread(void) {}
596#endif
597
598#endif /* __LINUX_RCU_H */