1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Read-Copy Update definitions shared among RCU implementations.
4 *
5 * Copyright IBM Corporation, 2011
6 *
7 * Author: Paul E. McKenney <paulmck@linux.ibm.com>
8 */
9
10 #ifndef __LINUX_RCU_H
11 #define __LINUX_RCU_H
12
13 #include <linux/slab.h>
14 #include <trace/events/rcu.h>
15
16 /*
17 * Grace-period counter management.
18 *
19 * The two least significant bits contain the control flags.
20 * The most significant bits contain the grace-period sequence counter.
21 *
22 * When both control flags are zero, no grace period is in progress.
23 * When either bit is non-zero, a grace period has started and is in
24 * progress. When the grace period completes, the control flags are reset
25 * to 0 and the grace-period sequence counter is incremented.
26 *
27 * However some specific RCU usages make use of custom values.
28 *
29 * SRCU special control values:
30 *
31 * SRCU_SNP_INIT_SEQ : Invalid/init value set when SRCU node
32 * is initialized.
33 *
34 * SRCU_STATE_IDLE : No SRCU gp is in progress
35 *
36 * SRCU_STATE_SCAN1 : State set by rcu_seq_start(). Indicates
37 * we are scanning the readers on the slot
38 * defined as inactive (there might well
39 * be pending readers that will use that
40 * index, but their number is bounded).
41 *
42 * SRCU_STATE_SCAN2 : State set manually via rcu_seq_set_state()
43 * Indicates we are flipping the readers
44 * index and then scanning the readers on the
45 * slot newly designated as inactive (again,
46 * the number of pending readers that will use
47 * this inactive index is bounded).
48 *
49 * RCU polled GP special control value:
50 *
51 * RCU_GET_STATE_COMPLETED : State value indicating an already-completed
52 * polled GP has completed. This value covers
53 * both the state and the counter of the
54 * grace-period sequence number.
55 */
56
57 /* Low-order bit definition for polled grace-period APIs. */
58 #define RCU_GET_STATE_COMPLETED 0x1
59
60 extern 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 */
rcu_seq_ctr(unsigned long s)66 static 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 */
rcu_seq_state(unsigned long s)75 static 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 */
rcu_seq_set_state(unsigned long * sp,int newstate)84 static 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. */
rcu_seq_start(unsigned long * sp)91 static 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. */
rcu_seq_endval(unsigned long * sp)99 static 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. */
rcu_seq_end(unsigned long * sp)105 static 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 */
rcu_seq_snap(unsigned long * sp)123 static 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. */
rcu_seq_current(unsigned long * sp)133 static 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 */
rcu_seq_started(unsigned long * sp,unsigned long s)142 static 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 */
rcu_seq_done(unsigned long * sp,unsigned long s)151 static 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 */
rcu_seq_done_exact(unsigned long * sp,unsigned long s)161 static 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 */
rcu_seq_completed_gp(unsigned long old,unsigned long new)171 static 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 */
rcu_seq_new_gp(unsigned long old,unsigned long new)179 static 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 */
rcu_seq_diff(unsigned long new,unsigned long old)189 static 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
218 extern const struct debug_obj_descr rcuhead_debug_descr;
219
debug_rcu_head_queue(struct rcu_head * head)220 static 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
debug_rcu_head_unqueue(struct rcu_head * head)231 static 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 */
debug_rcu_head_queue(struct rcu_head * head)239 static inline int debug_rcu_head_queue(struct rcu_head *head)
240 {
241 return 0;
242 }
243
debug_rcu_head_unqueue(struct rcu_head * head)244 static inline void debug_rcu_head_unqueue(struct rcu_head *head)
245 {
246 }
247 #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
248
debug_rcu_head_callback(struct rcu_head * rhp)249 static inline void debug_rcu_head_callback(struct rcu_head *rhp)
250 {
251 if (unlikely(!rhp->func))
252 kmem_dump_obj(rhp);
253 }
254
rcu_barrier_cb_is_done(struct rcu_head * rhp)255 static inline bool rcu_barrier_cb_is_done(struct rcu_head *rhp)
256 {
257 return rhp->next == rhp;
258 }
259
260 extern int rcu_cpu_stall_suppress_at_boot;
261
rcu_stall_is_suppressed_at_boot(void)262 static 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
267 extern int rcu_cpu_stall_notifiers;
268
269 #ifdef CONFIG_RCU_STALL_COMMON
270
271 extern int rcu_cpu_stall_ftrace_dump;
272 extern int rcu_cpu_stall_suppress;
273 extern int rcu_cpu_stall_timeout;
274 extern int rcu_exp_cpu_stall_timeout;
275 extern int rcu_cpu_stall_cputime;
276 extern bool rcu_exp_stall_task_details __read_mostly;
277 int rcu_jiffies_till_stall_check(void);
278 int rcu_exp_jiffies_till_stall_check(void);
279
rcu_stall_is_suppressed(void)280 static 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() \
286 do { \
287 if (!rcu_cpu_stall_suppress) \
288 rcu_cpu_stall_suppress = 3; \
289 } while (0)
290
291 #define rcu_ftrace_dump_stall_unsuppress() \
292 do { \
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
rcu_stall_is_suppressed(void)299 static 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) \
318 do { \
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
330 void rcu_early_boot_tests(void);
331 void 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 */
337 extern void resched_cpu(int cpu);
338
339 #if !defined(CONFIG_TINY_RCU)
340
341 #include <linux/rcu_node_tree.h>
342
343 extern int rcu_num_lvls;
344 extern int num_rcu_lvl[];
345 extern int rcu_num_nodes;
346 static bool rcu_fanout_exact;
347 static 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 */
rcu_init_levelspread(int * levelspread,const int * levelcnt)353 static 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
376 extern 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) \
449 do { \
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) \
455 do { \
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) \
461 do { \
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) \
467 do { \
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) \
473 do { \
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) \
479 do { \
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. */
rcu_gp_is_normal(void)500 static inline bool rcu_gp_is_normal(void) { return true; }
rcu_gp_is_expedited(void)501 static inline bool rcu_gp_is_expedited(void) { return false; }
rcu_async_should_hurry(void)502 static inline bool rcu_async_should_hurry(void) { return false; }
rcu_expedite_gp(void)503 static inline void rcu_expedite_gp(void) { }
rcu_unexpedite_gp(void)504 static inline void rcu_unexpedite_gp(void) { }
rcu_async_hurry(void)505 static inline void rcu_async_hurry(void) { }
rcu_async_relax(void)506 static inline void rcu_async_relax(void) { }
rcu_cpu_online(int cpu)507 static inline bool rcu_cpu_online(int cpu) { return true; }
508 #else /* #ifdef CONFIG_TINY_RCU */
509 bool rcu_gp_is_normal(void); /* Internal RCU use. */
510 bool rcu_gp_is_expedited(void); /* Internal RCU use. */
511 bool rcu_async_should_hurry(void); /* Internal RCU use. */
512 void rcu_expedite_gp(void);
513 void rcu_unexpedite_gp(void);
514 void rcu_async_hurry(void);
515 void rcu_async_relax(void);
516 void rcupdate_announce_bootup_oddness(void);
517 bool rcu_cpu_online(int cpu);
518 #ifdef CONFIG_TASKS_RCU_GENERIC
519 void show_rcu_tasks_gp_kthreads(void);
520 #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
show_rcu_tasks_gp_kthreads(void)521 static 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
526 struct task_struct *get_rcu_tasks_gp_kthread(void);
527 void rcu_tasks_get_gp_data(int *flags, unsigned long *gp_seq);
528 #endif // # ifdef CONFIG_TASKS_RCU
529
530 #ifdef CONFIG_TASKS_RUDE_RCU
531 struct task_struct *get_rcu_tasks_rude_gp_kthread(void);
532 void 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
536 void rcu_tasks_trace_get_gp_data(int *flags, unsigned long *gp_seq);
537 #endif
538
539 #ifdef CONFIG_TASKS_RCU_GENERIC
540 void tasks_cblist_init_generic(void);
541 #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
tasks_cblist_init_generic(void)542 static 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
549 enum 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)
560 unsigned long rcu_get_jiffies_lazy_flush(void);
561 void rcu_set_jiffies_lazy_flush(unsigned long j);
562 #else
rcu_get_jiffies_lazy_flush(void)563 static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }
rcu_set_jiffies_lazy_flush(unsigned long j)564 static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }
565 #endif
566
567 #if defined(CONFIG_TREE_RCU)
568 void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq);
569 void 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);
574 void rcu_gp_set_torture_wait(int duration);
575 #else
rcutorture_get_gp_data(int * flags,unsigned long * gp_seq)576 static 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
582 void 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
rcu_gp_set_torture_wait(int duration)591 static inline void rcu_gp_set_torture_wait(int duration) { }
592 #endif
593
594 #ifdef CONFIG_TINY_SRCU
595
srcutorture_get_gp_data(struct srcu_struct * sp,int * flags,unsigned long * gp_seq)596 static 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
605 void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
606 unsigned long *gp_seq);
607
608 #endif
609
610 #ifdef CONFIG_TINY_RCU
rcu_watching_zero_in_eqs(int cpu,int * vp)611 static inline bool rcu_watching_zero_in_eqs(int cpu, int *vp) { return false; }
rcu_get_gp_seq(void)612 static inline unsigned long rcu_get_gp_seq(void) { return 0; }
rcu_exp_batches_completed(void)613 static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
614 static inline unsigned long
srcu_batches_completed(struct srcu_struct * sp)615 srcu_batches_completed(struct srcu_struct *sp) { return 0; }
rcu_force_quiescent_state(void)616 static inline void rcu_force_quiescent_state(void) { }
rcu_check_boost_fail(unsigned long gp_state,int * cpup)617 static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
show_rcu_gp_kthreads(void)618 static inline void show_rcu_gp_kthreads(void) { }
rcu_get_gp_kthreads_prio(void)619 static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
rcu_fwd_progress_check(unsigned long j)620 static inline void rcu_fwd_progress_check(unsigned long j) { }
rcu_gp_slow_register(atomic_t * rgssp)621 static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
rcu_gp_slow_unregister(atomic_t * rgssp)622 static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
623 #else /* #ifdef CONFIG_TINY_RCU */
624 bool rcu_watching_zero_in_eqs(int cpu, int *vp);
625 unsigned long rcu_get_gp_seq(void);
626 unsigned long rcu_exp_batches_completed(void);
627 unsigned long srcu_batches_completed(struct srcu_struct *sp);
628 bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
629 void show_rcu_gp_kthreads(void);
630 int rcu_get_gp_kthreads_prio(void);
631 void rcu_fwd_progress_check(unsigned long j);
632 void rcu_force_quiescent_state(void);
633 extern struct workqueue_struct *rcu_gp_wq;
634 extern struct kthread_worker *rcu_exp_gp_kworker;
635 void rcu_gp_slow_register(atomic_t *rgssp);
636 void rcu_gp_slow_unregister(atomic_t *rgssp);
637 #endif /* #else #ifdef CONFIG_TINY_RCU */
638
639 #ifdef CONFIG_RCU_NOCB_CPU
640 void rcu_bind_current_to_nocb(void);
641 #else
rcu_bind_current_to_nocb(void)642 static inline void rcu_bind_current_to_nocb(void) { }
643 #endif
644
645 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
646 void show_rcu_tasks_classic_gp_kthread(void);
647 #else
show_rcu_tasks_classic_gp_kthread(void)648 static inline void show_rcu_tasks_classic_gp_kthread(void) {}
649 #endif
650 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
651 void show_rcu_tasks_rude_gp_kthread(void);
652 #else
show_rcu_tasks_rude_gp_kthread(void)653 static inline void show_rcu_tasks_rude_gp_kthread(void) {}
654 #endif
655 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_TRACE_RCU)
656 void show_rcu_tasks_trace_gp_kthread(void);
657 #else
show_rcu_tasks_trace_gp_kthread(void)658 static inline void show_rcu_tasks_trace_gp_kthread(void) {}
659 #endif
660
661 #ifdef CONFIG_TINY_RCU
rcu_cpu_beenfullyonline(int cpu)662 static inline bool rcu_cpu_beenfullyonline(int cpu) { return true; }
663 #else
664 bool rcu_cpu_beenfullyonline(int cpu);
665 #endif
666
667 #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
668 int rcu_stall_notifier_call_chain(unsigned long val, void *v);
669 #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
rcu_stall_notifier_call_chain(unsigned long val,void * v)670 static 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 */
674