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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 <[email protected]>
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 values:
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 * RCU_GET_STATE_NOT_TRACKED : State value indicating that a GP component
57 * is not tracked by this subsystem and should
58 * not be checked. Used by SRCU and RCU Tasks
59 * which do not track expedited GPs, to prevent
60 * false-positive completion when their
61 * gp_seq entries are checked via
62 * poll_state_synchronize_rcu_full().
63 */
64
65/* Low-order bit definitions for polled grace-period APIs. */
66#define RCU_GET_STATE_COMPLETED 0x1
67#define RCU_GET_STATE_NOT_TRACKED 0x2
68
69/* A complete grace period count */
70#define RCU_SEQ_GP (RCU_SEQ_STATE_MASK + 1)
71
72extern int sysctl_sched_rt_runtime;
73
74/*
75 * Return the counter portion of a sequence number previously returned
76 * by rcu_seq_snap() or rcu_seq_current().
77 */
78static inline unsigned long rcu_seq_ctr(unsigned long s)
79{
80 return s >> RCU_SEQ_CTR_SHIFT;
81}
82
83/*
84 * Return the state portion of a sequence number previously returned
85 * by rcu_seq_snap() or rcu_seq_current().
86 */
87static inline int rcu_seq_state(unsigned long s)
88{
89 return s & RCU_SEQ_STATE_MASK;
90}
91
92/*
93 * Set the state portion of the pointed-to sequence number.
94 * The caller is responsible for preventing conflicting updates.
95 */
96static inline void rcu_seq_set_state(unsigned long *sp, int newstate)
97{
98 WARN_ON_ONCE(newstate & ~RCU_SEQ_STATE_MASK);
99 WRITE_ONCE(*sp, (*sp & ~RCU_SEQ_STATE_MASK) + newstate);
100}
101
102/* Adjust sequence number for start of update-side operation. */
103static inline void rcu_seq_start(unsigned long *sp)
104{
105 WRITE_ONCE(*sp, *sp + 1);
106 smp_mb(); /* Ensure update-side operation after counter increment. */
107 WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
108}
109
110/* Compute the end-of-grace-period value for the specified sequence number. */
111static inline unsigned long rcu_seq_endval(unsigned long *sp)
112{
113 return (*sp | RCU_SEQ_STATE_MASK) + 1;
114}
115
116/* Adjust sequence number for end of update-side operation. */
117static inline void rcu_seq_end(unsigned long *sp)
118{
119 smp_mb(); /* Ensure update-side operation before counter increment. */
120 WARN_ON_ONCE(!rcu_seq_state(*sp));
121 WRITE_ONCE(*sp, rcu_seq_endval(sp));
122}
123
124/*
125 * rcu_seq_snap - Take a snapshot of the update side's sequence number.
126 *
127 * This function returns the earliest value of the grace-period sequence number
128 * that will indicate that a full grace period has elapsed since the current
129 * time. Once the grace-period sequence number has reached this value, it will
130 * be safe to invoke all callbacks that have been registered prior to the
131 * current time. This value is the current grace-period number plus two to the
132 * power of the number of low-order bits reserved for state, then rounded up to
133 * the next value in which the state bits are all zero.
134 */
135static inline unsigned long rcu_seq_snap(unsigned long *sp)
136{
137 unsigned long s;
138
139 s = (READ_ONCE(*sp) + 2 * RCU_SEQ_STATE_MASK + 1) & ~RCU_SEQ_STATE_MASK;
140 smp_mb(); /* Above access must not bleed into critical section. */
141 return s;
142}
143
144/* Return the current value the update side's sequence number, no ordering. */
145static inline unsigned long rcu_seq_current(unsigned long *sp)
146{
147 return READ_ONCE(*sp);
148}
149
150/*
151 * Given a snapshot from rcu_seq_snap(), determine whether or not the
152 * corresponding update-side operation has started.
153 */
154static inline bool rcu_seq_started(unsigned long *sp, unsigned long s)
155{
156 return ULONG_CMP_LT((s - 1) & ~RCU_SEQ_STATE_MASK, READ_ONCE(*sp));
157}
158
159/*
160 * Given a snapshot from rcu_seq_snap(), determine whether or not a
161 * full update-side operation has occurred.
162 */
163static inline bool rcu_seq_done(unsigned long *sp, unsigned long s)
164{
165 return ULONG_CMP_GE(READ_ONCE(*sp), s);
166}
167
168/*
169 * Given a snapshot from rcu_seq_snap(), determine whether or not a
170 * full update-side operation has occurred, but do not allow the
171 * (ULONG_MAX / 2) safety-factor/guard-band.
172 *
173 * The token returned by get_state_synchronize_rcu_full() is based on
174 * rcu_state.gp_seq but it is tested in poll_state_synchronize_rcu_full()
175 * against the root rnp->gp_seq. Since rcu_seq_start() is first called
176 * on rcu_state.gp_seq and only later reflected on the root rnp->gp_seq,
177 * it is possible that rcu_seq_snap(rcu_state.gp_seq) returns 2 full grace
178 * periods ahead of the root rnp->gp_seq. To prevent false-positives with the
179 * full polling API that a wrap around instantly completed the GP, when nothing
180 * like that happened, adjust for the 2 GPs in the ULONG_CMP_LT().
181 */
182static inline bool rcu_seq_done_exact(unsigned long *sp, unsigned long s)
183{
184 unsigned long cur_s = READ_ONCE(*sp);
185
186 return ULONG_CMP_GE(cur_s, s) || ULONG_CMP_LT(cur_s, s - (2 * RCU_SEQ_GP));
187}
188
189/*
190 * Has a grace period completed since the time the old gp_seq was collected?
191 */
192static inline bool rcu_seq_completed_gp(unsigned long old, unsigned long new)
193{
194 return ULONG_CMP_LT(old, new & ~RCU_SEQ_STATE_MASK);
195}
196
197/*
198 * Has a grace period started since the time the old gp_seq was collected?
199 */
200static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new)
201{
202 return ULONG_CMP_LT((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK,
203 new);
204}
205
206/*
207 * Roughly how many full grace periods have elapsed between the collection
208 * of the two specified grace periods?
209 */
210static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old)
211{
212 unsigned long rnd_diff;
213
214 if (old == new)
215 return 0;
216 /*
217 * Compute the number of grace periods (still shifted up), plus
218 * one if either of new and old is not an exact grace period.
219 */
220 rnd_diff = (new & ~RCU_SEQ_STATE_MASK) -
221 ((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK) +
222 ((new & RCU_SEQ_STATE_MASK) || (old & RCU_SEQ_STATE_MASK));
223 if (ULONG_CMP_GE(RCU_SEQ_STATE_MASK, rnd_diff))
224 return 1; /* Definitely no grace period has elapsed. */
225 return ((rnd_diff - RCU_SEQ_STATE_MASK - 1) >> RCU_SEQ_CTR_SHIFT) + 2;
226}
227
228/*
229 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
230 * by call_rcu() and rcu callback execution, and are therefore not part
231 * of the RCU API. These are in rcupdate.h because they are used by all
232 * RCU implementations.
233 */
234
235#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
236# define STATE_RCU_HEAD_READY 0
237# define STATE_RCU_HEAD_QUEUED 1
238
239extern const struct debug_obj_descr rcuhead_debug_descr;
240
241static inline int debug_rcu_head_queue(struct rcu_head *head)
242{
243 int r1;
244
245 r1 = debug_object_activate(head, &rcuhead_debug_descr);
246 debug_object_active_state(head, &rcuhead_debug_descr,
247 STATE_RCU_HEAD_READY,
248 STATE_RCU_HEAD_QUEUED);
249 return r1;
250}
251
252static inline void debug_rcu_head_unqueue(struct rcu_head *head)
253{
254 debug_object_active_state(head, &rcuhead_debug_descr,
255 STATE_RCU_HEAD_QUEUED,
256 STATE_RCU_HEAD_READY);
257 debug_object_deactivate(head, &rcuhead_debug_descr);
258}
259#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
260static inline int debug_rcu_head_queue(struct rcu_head *head)
261{
262 return 0;
263}
264
265static inline void debug_rcu_head_unqueue(struct rcu_head *head)
266{
267}
268#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
269
270static inline void debug_rcu_head_callback(struct rcu_head *rhp)
271{
272 if (unlikely(!rhp->func))
273 kmem_dump_obj(rhp);
274}
275
276static inline bool rcu_barrier_cb_is_done(struct rcu_head *rhp)
277{
278 return rhp->next == rhp;
279}
280
281extern int rcu_cpu_stall_suppress_at_boot;
282
283static inline bool rcu_stall_is_suppressed_at_boot(void)
284{
285 return rcu_cpu_stall_suppress_at_boot && !rcu_inkernel_boot_has_ended();
286}
287
288extern int rcu_cpu_stall_notifiers;
289
290#ifdef CONFIG_RCU_STALL_COMMON
291
292extern int rcu_cpu_stall_ftrace_dump;
293extern int rcu_cpu_stall_suppress;
294extern int rcu_cpu_stall_timeout;
295extern int rcu_exp_cpu_stall_timeout;
296extern int rcu_cpu_stall_cputime;
297extern bool rcu_exp_stall_task_details __read_mostly;
298int rcu_jiffies_till_stall_check(void);
299int rcu_exp_jiffies_till_stall_check(void);
300
301static inline bool rcu_stall_is_suppressed(void)
302{
303 return rcu_stall_is_suppressed_at_boot() || rcu_cpu_stall_suppress;
304}
305
306#define rcu_ftrace_dump_stall_suppress() \
307do { \
308 if (!rcu_cpu_stall_suppress) \
309 rcu_cpu_stall_suppress = 3; \
310} while (0)
311
312#define rcu_ftrace_dump_stall_unsuppress() \
313do { \
314 if (rcu_cpu_stall_suppress == 3) \
315 rcu_cpu_stall_suppress = 0; \
316} while (0)
317
318#else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
319
320static inline bool rcu_stall_is_suppressed(void)
321{
322 return rcu_stall_is_suppressed_at_boot();
323}
324#define rcu_ftrace_dump_stall_suppress()
325#define rcu_ftrace_dump_stall_unsuppress()
326#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
327
328/*
329 * Strings used in tracepoints need to be exported via the
330 * tracing system such that tools like perf and trace-cmd can
331 * translate the string address pointers to actual text.
332 */
333#define TPS(x) tracepoint_string(x)
334
335/*
336 * Dump the ftrace buffer, but only one time per callsite per boot.
337 */
338#define rcu_ftrace_dump(oops_dump_mode) \
339do { \
340 static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
341 \
342 if (!atomic_read(&___rfd_beenhere) && \
343 !atomic_xchg(&___rfd_beenhere, 1)) { \
344 tracing_off(); \
345 rcu_ftrace_dump_stall_suppress(); \
346 ftrace_dump(oops_dump_mode); \
347 rcu_ftrace_dump_stall_unsuppress(); \
348 } \
349} while (0)
350
351void rcu_early_boot_tests(void);
352void rcu_test_sync_prims(void);
353
354/*
355 * This function really isn't for public consumption, but RCU is special in
356 * that context switches can allow the state machine to make progress.
357 */
358extern void resched_cpu(int cpu);
359
360#if !defined(CONFIG_TINY_RCU)
361
362#include <linux/rcu_node_tree.h>
363
364extern int rcu_num_lvls;
365extern int num_rcu_lvl[];
366extern int rcu_num_nodes;
367static bool rcu_fanout_exact;
368static int rcu_fanout_leaf;
369
370/*
371 * Compute the per-level fanout, either using the exact fanout specified
372 * or balancing the tree, depending on the rcu_fanout_exact boot parameter.
373 */
374static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
375{
376 int i;
377
378 for (i = 0; i < RCU_NUM_LVLS; i++)
379 levelspread[i] = INT_MIN;
380 if (rcu_fanout_exact) {
381 levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
382 for (i = rcu_num_lvls - 2; i >= 0; i--)
383 levelspread[i] = RCU_FANOUT;
384 } else {
385 int ccur;
386 int cprv;
387
388 cprv = nr_cpu_ids;
389 for (i = rcu_num_lvls - 1; i >= 0; i--) {
390 ccur = levelcnt[i];
391 levelspread[i] = (cprv + ccur - 1) / ccur;
392 cprv = ccur;
393 }
394 }
395}
396
397extern void rcu_init_geometry(void);
398
399/* Returns a pointer to the first leaf rcu_node structure. */
400#define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
401
402/* Is this rcu_node a leaf? */
403#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
404
405/* Is this rcu_node the last leaf? */
406#define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])
407
408/*
409 * Do a full breadth-first scan of the {s,}rcu_node structures for the
410 * specified state structure (for SRCU) or the only rcu_state structure
411 * (for RCU).
412 */
413#define _rcu_for_each_node_breadth_first(sp, rnp) \
414 for ((rnp) = &(sp)->node[0]; \
415 (rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
416#define rcu_for_each_node_breadth_first(rnp) \
417 _rcu_for_each_node_breadth_first(&rcu_state, rnp)
418#define srcu_for_each_node_breadth_first(ssp, rnp) \
419 _rcu_for_each_node_breadth_first(ssp->srcu_sup, rnp)
420
421/*
422 * Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
423 * Note that if there is a singleton rcu_node tree with but one rcu_node
424 * structure, this loop -will- visit the rcu_node structure. It is still
425 * a leaf node, even if it is also the root node.
426 */
427#define rcu_for_each_leaf_node(rnp) \
428 for ((rnp) = rcu_first_leaf_node(); \
429 (rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)
430
431/*
432 * Iterate over all possible CPUs in a leaf RCU node.
433 */
434#define for_each_leaf_node_possible_cpu(rnp, cpu) \
435 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
436 (cpu) = cpumask_next((rnp)->grplo - 1, cpu_possible_mask); \
437 (cpu) <= rnp->grphi; \
438 (cpu) = cpumask_next((cpu), cpu_possible_mask))
439
440/*
441 * Iterate over all CPUs in a leaf RCU node's specified mask.
442 */
443#define rcu_find_next_bit(rnp, cpu, mask) \
444 ((rnp)->grplo + find_next_bit(&(mask), BITS_PER_LONG, (cpu)))
445#define for_each_leaf_node_cpu_mask(rnp, cpu, mask) \
446 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
447 (cpu) = rcu_find_next_bit((rnp), 0, (mask)); \
448 (cpu) <= rnp->grphi; \
449 (cpu) = rcu_find_next_bit((rnp), (cpu) + 1 - (rnp->grplo), (mask)))
450
451#endif /* !defined(CONFIG_TINY_RCU) */
452
453#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
454
455/*
456 * Wrappers for the rcu_node::lock acquire and release.
457 *
458 * Because the rcu_nodes form a tree, the tree traversal locking will observe
459 * different lock values, this in turn means that an UNLOCK of one level
460 * followed by a LOCK of another level does not imply a full memory barrier;
461 * and most importantly transitivity is lost.
462 *
463 * In order to restore full ordering between tree levels, augment the regular
464 * lock acquire functions with smp_mb__after_unlock_lock().
465 *
466 * As ->lock of struct rcu_node is a __private field, therefore one should use
467 * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
468 */
469#define raw_spin_lock_rcu_node(p) \
470do { \
471 raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \
472 smp_mb__after_unlock_lock(); \
473} while (0)
474
475#define raw_spin_unlock_rcu_node(p) \
476do { \
477 lockdep_assert_irqs_disabled(); \
478 raw_spin_unlock(&ACCESS_PRIVATE(p, lock)); \
479} while (0)
480
481#define raw_spin_lock_irq_rcu_node(p) \
482do { \
483 raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \
484 smp_mb__after_unlock_lock(); \
485} while (0)
486
487#define raw_spin_unlock_irq_rcu_node(p) \
488do { \
489 lockdep_assert_irqs_disabled(); \
490 raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock)); \
491} while (0)
492
493#define raw_spin_lock_irqsave_rcu_node(p, flags) \
494do { \
495 raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
496 smp_mb__after_unlock_lock(); \
497} while (0)
498
499#define raw_spin_unlock_irqrestore_rcu_node(p, flags) \
500do { \
501 lockdep_assert_irqs_disabled(); \
502 raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags); \
503} while (0)
504
505#define raw_spin_trylock_rcu_node(p) \
506({ \
507 bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \
508 \
509 if (___locked) \
510 smp_mb__after_unlock_lock(); \
511 ___locked; \
512})
513
514#define raw_spin_trylock_irqsave_rcu_node(p, flags) \
515({ \
516 bool ___locked = raw_spin_trylock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
517 \
518 if (___locked) \
519 smp_mb__after_unlock_lock(); \
520 ___locked; \
521})
522
523#define raw_lockdep_assert_held_rcu_node(p) \
524 lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
525
526#endif // #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
527
528#ifdef CONFIG_TINY_RCU
529/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
530static inline bool rcu_gp_is_normal(void) { return true; }
531static inline bool rcu_gp_is_expedited(void) { return false; }
532static inline bool rcu_async_should_hurry(void) { return false; }
533static inline void rcu_expedite_gp(void) { }
534static inline void rcu_unexpedite_gp(void) { }
535static inline void rcu_async_hurry(void) { }
536static inline void rcu_async_relax(void) { }
537static inline bool rcu_cpu_online(int cpu) { return true; }
538#else /* #ifdef CONFIG_TINY_RCU */
539bool rcu_gp_is_normal(void); /* Internal RCU use. */
540bool rcu_gp_is_expedited(void); /* Internal RCU use. */
541bool rcu_async_should_hurry(void); /* Internal RCU use. */
542void rcu_expedite_gp(void);
543void rcu_unexpedite_gp(void);
544void rcu_async_hurry(void);
545void rcu_async_relax(void);
546void rcupdate_announce_bootup_oddness(void);
547bool rcu_cpu_online(int cpu);
548#ifdef CONFIG_TASKS_RCU_GENERIC
549void show_rcu_tasks_gp_kthreads(void);
550#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
551static inline void show_rcu_tasks_gp_kthreads(void) {}
552#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
553#endif /* #else #ifdef CONFIG_TINY_RCU */
554
555#ifdef CONFIG_TASKS_RCU
556struct task_struct *get_rcu_tasks_gp_kthread(void);
557void rcu_tasks_get_gp_data(int *flags, unsigned long *gp_seq);
558#endif // # ifdef CONFIG_TASKS_RCU
559
560#ifdef CONFIG_TASKS_RUDE_RCU
561struct task_struct *get_rcu_tasks_rude_gp_kthread(void);
562void rcu_tasks_rude_get_gp_data(int *flags, unsigned long *gp_seq);
563#endif // # ifdef CONFIG_TASKS_RUDE_RCU
564
565#ifdef CONFIG_TASKS_RCU_GENERIC
566void tasks_cblist_init_generic(void);
567#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
568static inline void tasks_cblist_init_generic(void) { }
569#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
570
571#define RCU_SCHEDULER_INACTIVE 0
572#define RCU_SCHEDULER_INIT 1
573#define RCU_SCHEDULER_RUNNING 2
574
575enum rcutorture_type {
576 RCU_FLAVOR,
577 RCU_TASKS_FLAVOR,
578 RCU_TASKS_RUDE_FLAVOR,
579 RCU_TASKS_TRACING_FLAVOR,
580 RCU_TRIVIAL_FLAVOR,
581 SRCU_FLAVOR,
582 INVALID_RCU_FLAVOR
583};
584
585#if defined(CONFIG_RCU_LAZY)
586unsigned long rcu_get_jiffies_lazy_flush(void);
587void rcu_set_jiffies_lazy_flush(unsigned long j);
588#else
589static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }
590static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }
591#endif
592
593#if defined(CONFIG_TREE_RCU)
594void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq);
595void do_trace_rcu_torture_read(const char *rcutorturename,
596 struct rcu_head *rhp,
597 unsigned long secs,
598 unsigned long c_old,
599 unsigned long c);
600void rcu_gp_set_torture_wait(int duration);
601void rcu_set_gpwrap_lag(unsigned long lag);
602int rcu_get_gpwrap_count(int cpu);
603#else
604static inline void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq)
605{
606 *flags = 0;
607 *gp_seq = 0;
608}
609#ifdef CONFIG_RCU_TRACE
610void do_trace_rcu_torture_read(const char *rcutorturename,
611 struct rcu_head *rhp,
612 unsigned long secs,
613 unsigned long c_old,
614 unsigned long c);
615#else
616#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
617 do { } while (0)
618#endif
619static inline void rcu_gp_set_torture_wait(int duration) { }
620static inline void rcu_set_gpwrap_lag(unsigned long lag) { }
621static inline int rcu_get_gpwrap_count(int cpu) { return 0; }
622#endif
623unsigned long long rcutorture_gather_gp_seqs(void);
624void rcutorture_format_gp_seqs(unsigned long long seqs, char *cp, size_t len);
625
626#ifdef CONFIG_TINY_SRCU
627
628static inline void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
629 unsigned long *gp_seq)
630{
631 *flags = 0;
632 *gp_seq = sp->srcu_idx;
633}
634
635#elif defined(CONFIG_TREE_SRCU)
636
637void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
638 unsigned long *gp_seq);
639
640#endif
641
642#ifdef CONFIG_TINY_RCU
643static inline bool rcu_watching_zero_in_eqs(int cpu, int *vp) { return false; }
644static inline unsigned long rcu_get_gp_seq(void) { return 0; }
645static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
646static inline void rcu_force_quiescent_state(void) { }
647static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
648static inline void show_rcu_gp_kthreads(void) { }
649static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
650static inline void rcu_fwd_progress_check(unsigned long j) { }
651static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
652static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
653#else /* #ifdef CONFIG_TINY_RCU */
654bool rcu_watching_zero_in_eqs(int cpu, int *vp);
655unsigned long rcu_get_gp_seq(void);
656unsigned long rcu_exp_batches_completed(void);
657bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
658void show_rcu_gp_kthreads(void);
659int rcu_get_gp_kthreads_prio(void);
660void rcu_fwd_progress_check(unsigned long j);
661void rcu_force_quiescent_state(void);
662extern struct workqueue_struct *rcu_gp_wq;
663extern struct kthread_worker *rcu_exp_gp_kworker;
664void rcu_gp_slow_register(atomic_t *rgssp);
665void rcu_gp_slow_unregister(atomic_t *rgssp);
666#endif /* #else #ifdef CONFIG_TINY_RCU */
667
668#ifdef CONFIG_TINY_SRCU
669static inline unsigned long srcu_batches_completed(struct srcu_struct *sp) { return 0; }
670#else // #ifdef CONFIG_TINY_SRCU
671unsigned long srcu_batches_completed(struct srcu_struct *sp);
672#endif // #else // #ifdef CONFIG_TINY_SRCU
673
674#ifdef CONFIG_RCU_NOCB_CPU
675void rcu_bind_current_to_nocb(void);
676#else
677static inline void rcu_bind_current_to_nocb(void) { }
678#endif
679
680#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
681void show_rcu_tasks_classic_gp_kthread(void);
682#else
683static inline void show_rcu_tasks_classic_gp_kthread(void) {}
684#endif
685#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
686void show_rcu_tasks_rude_gp_kthread(void);
687#else
688static inline void show_rcu_tasks_rude_gp_kthread(void) {}
689#endif
690
691#ifdef CONFIG_TINY_RCU
692static inline bool rcu_cpu_beenfullyonline(int cpu) { return true; }
693#else
694bool rcu_cpu_beenfullyonline(int cpu);
695#endif
696
697#if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
698int rcu_stall_notifier_call_chain(unsigned long val, void *v);
699#else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
700static inline int rcu_stall_notifier_call_chain(unsigned long val, void *v) { return NOTIFY_DONE; }
701#endif // #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
702
703#ifdef CONFIG_TRIVIAL_PREEMPT_RCU
704void synchronize_rcu_trivial_preempt(void);
705#endif // #ifdef CONFIG_TRIVIAL_PREEMPT_RCU
706
707#if defined(CONFIG_RCU_TORTURE_TEST) && defined(CONFIG_RCU_BOOST)
708bool rcu_is_task_rcu_boosted(void);
709#else // #if defined(CONFIG_RCU_TORTURE_TEST) && defined(CONFIG_RCU_BOOST)
710static inline bool rcu_is_task_rcu_boosted(void) { return false; }
711#endif // #else // #if defined(CONFIG_RCU_TORTURE_TEST) && defined(CONFIG_RCU_BOOST)
712
713
714#endif /* __LINUX_RCU_H */