1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Read-Copy Update definitions shared among RCU implementations.
4 *
5 * Copyright IBM Corporation, 2011
6 *
7 * Author: Paul E. McKenney <paulmck@linux.ibm.com>
8 */
9
10 #ifndef __LINUX_RCU_H
11 #define __LINUX_RCU_H
12
13 #include <linux/slab.h>
14 #include <trace/events/rcu.h>
15
16 /*
17 * Grace-period counter management.
18 *
19 * The two least significant bits contain the control flags.
20 * The most significant bits contain the grace-period sequence counter.
21 *
22 * When both control flags are zero, no grace period is in progress.
23 * When either bit is non-zero, a grace period has started and is in
24 * progress. When the grace period completes, the control flags are reset
25 * to 0 and the grace-period sequence counter is incremented.
26 *
27 * However some specific RCU usages make use of custom values.
28 *
29 * SRCU special control values:
30 *
31 * SRCU_SNP_INIT_SEQ : Invalid/init value set when SRCU node
32 * is initialized.
33 *
34 * SRCU_STATE_IDLE : No SRCU gp is in progress
35 *
36 * SRCU_STATE_SCAN1 : State set by rcu_seq_start(). Indicates
37 * we are scanning the readers on the slot
38 * defined as inactive (there might well
39 * be pending readers that will use that
40 * index, but their number is bounded).
41 *
42 * SRCU_STATE_SCAN2 : State set manually via rcu_seq_set_state()
43 * Indicates we are flipping the readers
44 * index and then scanning the readers on the
45 * slot newly designated as inactive (again,
46 * the number of pending readers that will use
47 * this inactive index is bounded).
48 *
49 * RCU polled GP special control value:
50 *
51 * RCU_GET_STATE_COMPLETED : State value indicating an already-completed
52 * polled GP has completed. This value covers
53 * both the state and the counter of the
54 * grace-period sequence number.
55 */
56
57 /* Low-order bit definition for polled grace-period APIs. */
58 #define RCU_GET_STATE_COMPLETED 0x1
59
60 /* A complete grace period count */
61 #define RCU_SEQ_GP (RCU_SEQ_STATE_MASK + 1)
62
63 extern int sysctl_sched_rt_runtime;
64
65 /*
66 * Return the counter portion of a sequence number previously returned
67 * by rcu_seq_snap() or rcu_seq_current().
68 */
rcu_seq_ctr(unsigned long s)69 static inline unsigned long rcu_seq_ctr(unsigned long s)
70 {
71 return s >> RCU_SEQ_CTR_SHIFT;
72 }
73
74 /*
75 * Return the state portion of a sequence number previously returned
76 * by rcu_seq_snap() or rcu_seq_current().
77 */
rcu_seq_state(unsigned long s)78 static inline int rcu_seq_state(unsigned long s)
79 {
80 return s & RCU_SEQ_STATE_MASK;
81 }
82
83 /*
84 * Set the state portion of the pointed-to sequence number.
85 * The caller is responsible for preventing conflicting updates.
86 */
rcu_seq_set_state(unsigned long * sp,int newstate)87 static inline void rcu_seq_set_state(unsigned long *sp, int newstate)
88 {
89 WARN_ON_ONCE(newstate & ~RCU_SEQ_STATE_MASK);
90 WRITE_ONCE(*sp, (*sp & ~RCU_SEQ_STATE_MASK) + newstate);
91 }
92
93 /* Adjust sequence number for start of update-side operation. */
rcu_seq_start(unsigned long * sp)94 static inline void rcu_seq_start(unsigned long *sp)
95 {
96 WRITE_ONCE(*sp, *sp + 1);
97 smp_mb(); /* Ensure update-side operation after counter increment. */
98 WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
99 }
100
101 /* Compute the end-of-grace-period value for the specified sequence number. */
rcu_seq_endval(unsigned long * sp)102 static inline unsigned long rcu_seq_endval(unsigned long *sp)
103 {
104 return (*sp | RCU_SEQ_STATE_MASK) + 1;
105 }
106
107 /* Adjust sequence number for end of update-side operation. */
rcu_seq_end(unsigned long * sp)108 static inline void rcu_seq_end(unsigned long *sp)
109 {
110 smp_mb(); /* Ensure update-side operation before counter increment. */
111 WARN_ON_ONCE(!rcu_seq_state(*sp));
112 WRITE_ONCE(*sp, rcu_seq_endval(sp));
113 }
114
115 /*
116 * rcu_seq_snap - Take a snapshot of the update side's sequence number.
117 *
118 * This function returns the earliest value of the grace-period sequence number
119 * that will indicate that a full grace period has elapsed since the current
120 * time. Once the grace-period sequence number has reached this value, it will
121 * be safe to invoke all callbacks that have been registered prior to the
122 * current time. This value is the current grace-period number plus two to the
123 * power of the number of low-order bits reserved for state, then rounded up to
124 * the next value in which the state bits are all zero.
125 */
rcu_seq_snap(unsigned long * sp)126 static inline unsigned long rcu_seq_snap(unsigned long *sp)
127 {
128 unsigned long s;
129
130 s = (READ_ONCE(*sp) + 2 * RCU_SEQ_STATE_MASK + 1) & ~RCU_SEQ_STATE_MASK;
131 smp_mb(); /* Above access must not bleed into critical section. */
132 return s;
133 }
134
135 /* Return the current value the update side's sequence number, no ordering. */
rcu_seq_current(unsigned long * sp)136 static inline unsigned long rcu_seq_current(unsigned long *sp)
137 {
138 return READ_ONCE(*sp);
139 }
140
141 /*
142 * Given a snapshot from rcu_seq_snap(), determine whether or not the
143 * corresponding update-side operation has started.
144 */
rcu_seq_started(unsigned long * sp,unsigned long s)145 static inline bool rcu_seq_started(unsigned long *sp, unsigned long s)
146 {
147 return ULONG_CMP_LT((s - 1) & ~RCU_SEQ_STATE_MASK, READ_ONCE(*sp));
148 }
149
150 /*
151 * Given a snapshot from rcu_seq_snap(), determine whether or not a
152 * full update-side operation has occurred.
153 */
rcu_seq_done(unsigned long * sp,unsigned long s)154 static inline bool rcu_seq_done(unsigned long *sp, unsigned long s)
155 {
156 return ULONG_CMP_GE(READ_ONCE(*sp), s);
157 }
158
159 /*
160 * Given a snapshot from rcu_seq_snap(), determine whether or not a
161 * full update-side operation has occurred, but do not allow the
162 * (ULONG_MAX / 2) safety-factor/guard-band.
163 *
164 * The token returned by get_state_synchronize_rcu_full() is based on
165 * rcu_state.gp_seq but it is tested in poll_state_synchronize_rcu_full()
166 * against the root rnp->gp_seq. Since rcu_seq_start() is first called
167 * on rcu_state.gp_seq and only later reflected on the root rnp->gp_seq,
168 * it is possible that rcu_seq_snap(rcu_state.gp_seq) returns 2 full grace
169 * periods ahead of the root rnp->gp_seq. To prevent false-positives with the
170 * full polling API that a wrap around instantly completed the GP, when nothing
171 * like that happened, adjust for the 2 GPs in the ULONG_CMP_LT().
172 */
rcu_seq_done_exact(unsigned long * sp,unsigned long s)173 static inline bool rcu_seq_done_exact(unsigned long *sp, unsigned long s)
174 {
175 unsigned long cur_s = READ_ONCE(*sp);
176
177 return ULONG_CMP_GE(cur_s, s) || ULONG_CMP_LT(cur_s, s - (2 * RCU_SEQ_GP));
178 }
179
180 /*
181 * Has a grace period completed since the time the old gp_seq was collected?
182 */
rcu_seq_completed_gp(unsigned long old,unsigned long new)183 static inline bool rcu_seq_completed_gp(unsigned long old, unsigned long new)
184 {
185 return ULONG_CMP_LT(old, new & ~RCU_SEQ_STATE_MASK);
186 }
187
188 /*
189 * Has a grace period started since the time the old gp_seq was collected?
190 */
rcu_seq_new_gp(unsigned long old,unsigned long new)191 static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new)
192 {
193 return ULONG_CMP_LT((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK,
194 new);
195 }
196
197 /*
198 * Roughly how many full grace periods have elapsed between the collection
199 * of the two specified grace periods?
200 */
rcu_seq_diff(unsigned long new,unsigned long old)201 static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old)
202 {
203 unsigned long rnd_diff;
204
205 if (old == new)
206 return 0;
207 /*
208 * Compute the number of grace periods (still shifted up), plus
209 * one if either of new and old is not an exact grace period.
210 */
211 rnd_diff = (new & ~RCU_SEQ_STATE_MASK) -
212 ((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK) +
213 ((new & RCU_SEQ_STATE_MASK) || (old & RCU_SEQ_STATE_MASK));
214 if (ULONG_CMP_GE(RCU_SEQ_STATE_MASK, rnd_diff))
215 return 1; /* Definitely no grace period has elapsed. */
216 return ((rnd_diff - RCU_SEQ_STATE_MASK - 1) >> RCU_SEQ_CTR_SHIFT) + 2;
217 }
218
219 /*
220 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
221 * by call_rcu() and rcu callback execution, and are therefore not part
222 * of the RCU API. These are in rcupdate.h because they are used by all
223 * RCU implementations.
224 */
225
226 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
227 # define STATE_RCU_HEAD_READY 0
228 # define STATE_RCU_HEAD_QUEUED 1
229
230 extern const struct debug_obj_descr rcuhead_debug_descr;
231
debug_rcu_head_queue(struct rcu_head * head)232 static inline int debug_rcu_head_queue(struct rcu_head *head)
233 {
234 int r1;
235
236 r1 = debug_object_activate(head, &rcuhead_debug_descr);
237 debug_object_active_state(head, &rcuhead_debug_descr,
238 STATE_RCU_HEAD_READY,
239 STATE_RCU_HEAD_QUEUED);
240 return r1;
241 }
242
debug_rcu_head_unqueue(struct rcu_head * head)243 static inline void debug_rcu_head_unqueue(struct rcu_head *head)
244 {
245 debug_object_active_state(head, &rcuhead_debug_descr,
246 STATE_RCU_HEAD_QUEUED,
247 STATE_RCU_HEAD_READY);
248 debug_object_deactivate(head, &rcuhead_debug_descr);
249 }
250 #else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
debug_rcu_head_queue(struct rcu_head * head)251 static inline int debug_rcu_head_queue(struct rcu_head *head)
252 {
253 return 0;
254 }
255
debug_rcu_head_unqueue(struct rcu_head * head)256 static inline void debug_rcu_head_unqueue(struct rcu_head *head)
257 {
258 }
259 #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
260
debug_rcu_head_callback(struct rcu_head * rhp)261 static inline void debug_rcu_head_callback(struct rcu_head *rhp)
262 {
263 if (unlikely(!rhp->func))
264 kmem_dump_obj(rhp);
265 }
266
rcu_barrier_cb_is_done(struct rcu_head * rhp)267 static inline bool rcu_barrier_cb_is_done(struct rcu_head *rhp)
268 {
269 return rhp->next == rhp;
270 }
271
272 extern int rcu_cpu_stall_suppress_at_boot;
273
rcu_stall_is_suppressed_at_boot(void)274 static inline bool rcu_stall_is_suppressed_at_boot(void)
275 {
276 return rcu_cpu_stall_suppress_at_boot && !rcu_inkernel_boot_has_ended();
277 }
278
279 extern int rcu_cpu_stall_notifiers;
280
281 #ifdef CONFIG_RCU_STALL_COMMON
282
283 extern int rcu_cpu_stall_ftrace_dump;
284 extern int rcu_cpu_stall_suppress;
285 extern int rcu_cpu_stall_timeout;
286 extern int rcu_exp_cpu_stall_timeout;
287 extern int rcu_cpu_stall_cputime;
288 extern bool rcu_exp_stall_task_details __read_mostly;
289 int rcu_jiffies_till_stall_check(void);
290 int rcu_exp_jiffies_till_stall_check(void);
291
rcu_stall_is_suppressed(void)292 static inline bool rcu_stall_is_suppressed(void)
293 {
294 return rcu_stall_is_suppressed_at_boot() || rcu_cpu_stall_suppress;
295 }
296
297 #define rcu_ftrace_dump_stall_suppress() \
298 do { \
299 if (!rcu_cpu_stall_suppress) \
300 rcu_cpu_stall_suppress = 3; \
301 } while (0)
302
303 #define rcu_ftrace_dump_stall_unsuppress() \
304 do { \
305 if (rcu_cpu_stall_suppress == 3) \
306 rcu_cpu_stall_suppress = 0; \
307 } while (0)
308
309 #else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
310
rcu_stall_is_suppressed(void)311 static inline bool rcu_stall_is_suppressed(void)
312 {
313 return rcu_stall_is_suppressed_at_boot();
314 }
315 #define rcu_ftrace_dump_stall_suppress()
316 #define rcu_ftrace_dump_stall_unsuppress()
317 #endif /* #ifdef CONFIG_RCU_STALL_COMMON */
318
319 /*
320 * Strings used in tracepoints need to be exported via the
321 * tracing system such that tools like perf and trace-cmd can
322 * translate the string address pointers to actual text.
323 */
324 #define TPS(x) tracepoint_string(x)
325
326 /*
327 * Dump the ftrace buffer, but only one time per callsite per boot.
328 */
329 #define rcu_ftrace_dump(oops_dump_mode) \
330 do { \
331 static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
332 \
333 if (!atomic_read(&___rfd_beenhere) && \
334 !atomic_xchg(&___rfd_beenhere, 1)) { \
335 tracing_off(); \
336 rcu_ftrace_dump_stall_suppress(); \
337 ftrace_dump(oops_dump_mode); \
338 rcu_ftrace_dump_stall_unsuppress(); \
339 } \
340 } while (0)
341
342 void rcu_early_boot_tests(void);
343 void rcu_test_sync_prims(void);
344
345 /*
346 * This function really isn't for public consumption, but RCU is special in
347 * that context switches can allow the state machine to make progress.
348 */
349 extern void resched_cpu(int cpu);
350
351 #if !defined(CONFIG_TINY_RCU)
352
353 #include <linux/rcu_node_tree.h>
354
355 extern int rcu_num_lvls;
356 extern int num_rcu_lvl[];
357 extern int rcu_num_nodes;
358 static bool rcu_fanout_exact;
359 static int rcu_fanout_leaf;
360
361 /*
362 * Compute the per-level fanout, either using the exact fanout specified
363 * or balancing the tree, depending on the rcu_fanout_exact boot parameter.
364 */
rcu_init_levelspread(int * levelspread,const int * levelcnt)365 static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
366 {
367 int i;
368
369 for (i = 0; i < RCU_NUM_LVLS; i++)
370 levelspread[i] = INT_MIN;
371 if (rcu_fanout_exact) {
372 levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
373 for (i = rcu_num_lvls - 2; i >= 0; i--)
374 levelspread[i] = RCU_FANOUT;
375 } else {
376 int ccur;
377 int cprv;
378
379 cprv = nr_cpu_ids;
380 for (i = rcu_num_lvls - 1; i >= 0; i--) {
381 ccur = levelcnt[i];
382 levelspread[i] = (cprv + ccur - 1) / ccur;
383 cprv = ccur;
384 }
385 }
386 }
387
388 extern void rcu_init_geometry(void);
389
390 /* Returns a pointer to the first leaf rcu_node structure. */
391 #define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
392
393 /* Is this rcu_node a leaf? */
394 #define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
395
396 /* Is this rcu_node the last leaf? */
397 #define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])
398
399 /*
400 * Do a full breadth-first scan of the {s,}rcu_node structures for the
401 * specified state structure (for SRCU) or the only rcu_state structure
402 * (for RCU).
403 */
404 #define _rcu_for_each_node_breadth_first(sp, rnp) \
405 for ((rnp) = &(sp)->node[0]; \
406 (rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
407 #define rcu_for_each_node_breadth_first(rnp) \
408 _rcu_for_each_node_breadth_first(&rcu_state, rnp)
409 #define srcu_for_each_node_breadth_first(ssp, rnp) \
410 _rcu_for_each_node_breadth_first(ssp->srcu_sup, rnp)
411
412 /*
413 * Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
414 * Note that if there is a singleton rcu_node tree with but one rcu_node
415 * structure, this loop -will- visit the rcu_node structure. It is still
416 * a leaf node, even if it is also the root node.
417 */
418 #define rcu_for_each_leaf_node(rnp) \
419 for ((rnp) = rcu_first_leaf_node(); \
420 (rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)
421
422 /*
423 * Iterate over all possible CPUs in a leaf RCU node.
424 */
425 #define for_each_leaf_node_possible_cpu(rnp, cpu) \
426 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
427 (cpu) = cpumask_next((rnp)->grplo - 1, cpu_possible_mask); \
428 (cpu) <= rnp->grphi; \
429 (cpu) = cpumask_next((cpu), cpu_possible_mask))
430
431 /*
432 * Iterate over all CPUs in a leaf RCU node's specified mask.
433 */
434 #define rcu_find_next_bit(rnp, cpu, mask) \
435 ((rnp)->grplo + find_next_bit(&(mask), BITS_PER_LONG, (cpu)))
436 #define for_each_leaf_node_cpu_mask(rnp, cpu, mask) \
437 for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
438 (cpu) = rcu_find_next_bit((rnp), 0, (mask)); \
439 (cpu) <= rnp->grphi; \
440 (cpu) = rcu_find_next_bit((rnp), (cpu) + 1 - (rnp->grplo), (mask)))
441
442 #endif /* !defined(CONFIG_TINY_RCU) */
443
444 #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
445
446 /*
447 * Wrappers for the rcu_node::lock acquire and release.
448 *
449 * Because the rcu_nodes form a tree, the tree traversal locking will observe
450 * different lock values, this in turn means that an UNLOCK of one level
451 * followed by a LOCK of another level does not imply a full memory barrier;
452 * and most importantly transitivity is lost.
453 *
454 * In order to restore full ordering between tree levels, augment the regular
455 * lock acquire functions with smp_mb__after_unlock_lock().
456 *
457 * As ->lock of struct rcu_node is a __private field, therefore one should use
458 * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
459 */
460 #define raw_spin_lock_rcu_node(p) \
461 do { \
462 raw_spin_lock(&ACCESS_PRIVATE(p, lock)); \
463 smp_mb__after_unlock_lock(); \
464 } while (0)
465
466 #define raw_spin_unlock_rcu_node(p) \
467 do { \
468 lockdep_assert_irqs_disabled(); \
469 raw_spin_unlock(&ACCESS_PRIVATE(p, lock)); \
470 } while (0)
471
472 #define raw_spin_lock_irq_rcu_node(p) \
473 do { \
474 raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock)); \
475 smp_mb__after_unlock_lock(); \
476 } while (0)
477
478 #define raw_spin_unlock_irq_rcu_node(p) \
479 do { \
480 lockdep_assert_irqs_disabled(); \
481 raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock)); \
482 } while (0)
483
484 #define raw_spin_lock_irqsave_rcu_node(p, flags) \
485 do { \
486 raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags); \
487 smp_mb__after_unlock_lock(); \
488 } while (0)
489
490 #define raw_spin_unlock_irqrestore_rcu_node(p, flags) \
491 do { \
492 lockdep_assert_irqs_disabled(); \
493 raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags); \
494 } while (0)
495
496 #define raw_spin_trylock_rcu_node(p) \
497 ({ \
498 bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock)); \
499 \
500 if (___locked) \
501 smp_mb__after_unlock_lock(); \
502 ___locked; \
503 })
504
505 #define raw_lockdep_assert_held_rcu_node(p) \
506 lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
507
508 #endif // #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_TASKS_RCU_GENERIC)
509
510 #ifdef CONFIG_TINY_RCU
511 /* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
rcu_gp_is_normal(void)512 static inline bool rcu_gp_is_normal(void) { return true; }
rcu_gp_is_expedited(void)513 static inline bool rcu_gp_is_expedited(void) { return false; }
rcu_async_should_hurry(void)514 static inline bool rcu_async_should_hurry(void) { return false; }
rcu_expedite_gp(void)515 static inline void rcu_expedite_gp(void) { }
rcu_unexpedite_gp(void)516 static inline void rcu_unexpedite_gp(void) { }
rcu_async_hurry(void)517 static inline void rcu_async_hurry(void) { }
rcu_async_relax(void)518 static inline void rcu_async_relax(void) { }
rcu_cpu_online(int cpu)519 static inline bool rcu_cpu_online(int cpu) { return true; }
520 #else /* #ifdef CONFIG_TINY_RCU */
521 bool rcu_gp_is_normal(void); /* Internal RCU use. */
522 bool rcu_gp_is_expedited(void); /* Internal RCU use. */
523 bool rcu_async_should_hurry(void); /* Internal RCU use. */
524 void rcu_expedite_gp(void);
525 void rcu_unexpedite_gp(void);
526 void rcu_async_hurry(void);
527 void rcu_async_relax(void);
528 void rcupdate_announce_bootup_oddness(void);
529 bool rcu_cpu_online(int cpu);
530 #ifdef CONFIG_TASKS_RCU_GENERIC
531 void show_rcu_tasks_gp_kthreads(void);
532 #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
show_rcu_tasks_gp_kthreads(void)533 static inline void show_rcu_tasks_gp_kthreads(void) {}
534 #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
535 #endif /* #else #ifdef CONFIG_TINY_RCU */
536
537 #ifdef CONFIG_TASKS_RCU
538 struct task_struct *get_rcu_tasks_gp_kthread(void);
539 void rcu_tasks_get_gp_data(int *flags, unsigned long *gp_seq);
540 #endif // # ifdef CONFIG_TASKS_RCU
541
542 #ifdef CONFIG_TASKS_RUDE_RCU
543 struct task_struct *get_rcu_tasks_rude_gp_kthread(void);
544 void rcu_tasks_rude_get_gp_data(int *flags, unsigned long *gp_seq);
545 #endif // # ifdef CONFIG_TASKS_RUDE_RCU
546
547 #ifdef CONFIG_TASKS_TRACE_RCU
548 void rcu_tasks_trace_get_gp_data(int *flags, unsigned long *gp_seq);
549 #endif
550
551 #ifdef CONFIG_TASKS_RCU_GENERIC
552 void tasks_cblist_init_generic(void);
553 #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
tasks_cblist_init_generic(void)554 static inline void tasks_cblist_init_generic(void) { }
555 #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
556
557 #define RCU_SCHEDULER_INACTIVE 0
558 #define RCU_SCHEDULER_INIT 1
559 #define RCU_SCHEDULER_RUNNING 2
560
561 enum rcutorture_type {
562 RCU_FLAVOR,
563 RCU_TASKS_FLAVOR,
564 RCU_TASKS_RUDE_FLAVOR,
565 RCU_TASKS_TRACING_FLAVOR,
566 RCU_TRIVIAL_FLAVOR,
567 SRCU_FLAVOR,
568 INVALID_RCU_FLAVOR
569 };
570
571 #if defined(CONFIG_RCU_LAZY)
572 unsigned long rcu_get_jiffies_lazy_flush(void);
573 void rcu_set_jiffies_lazy_flush(unsigned long j);
574 #else
rcu_get_jiffies_lazy_flush(void)575 static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }
rcu_set_jiffies_lazy_flush(unsigned long j)576 static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }
577 #endif
578
579 #if defined(CONFIG_TREE_RCU)
580 void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq);
581 void do_trace_rcu_torture_read(const char *rcutorturename,
582 struct rcu_head *rhp,
583 unsigned long secs,
584 unsigned long c_old,
585 unsigned long c);
586 void rcu_gp_set_torture_wait(int duration);
587 void rcu_set_gpwrap_lag(unsigned long lag);
588 int rcu_get_gpwrap_count(int cpu);
589 #else
rcutorture_get_gp_data(int * flags,unsigned long * gp_seq)590 static inline void rcutorture_get_gp_data(int *flags, unsigned long *gp_seq)
591 {
592 *flags = 0;
593 *gp_seq = 0;
594 }
595 #ifdef CONFIG_RCU_TRACE
596 void do_trace_rcu_torture_read(const char *rcutorturename,
597 struct rcu_head *rhp,
598 unsigned long secs,
599 unsigned long c_old,
600 unsigned long c);
601 #else
602 #define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
603 do { } while (0)
604 #endif
rcu_gp_set_torture_wait(int duration)605 static inline void rcu_gp_set_torture_wait(int duration) { }
rcu_set_gpwrap_lag(unsigned long lag)606 static inline void rcu_set_gpwrap_lag(unsigned long lag) { }
rcu_get_gpwrap_count(int cpu)607 static inline int rcu_get_gpwrap_count(int cpu) { return 0; }
608 #endif
609 unsigned long long rcutorture_gather_gp_seqs(void);
610 void rcutorture_format_gp_seqs(unsigned long long seqs, char *cp, size_t len);
611
612 #ifdef CONFIG_TINY_SRCU
613
srcutorture_get_gp_data(struct srcu_struct * sp,int * flags,unsigned long * gp_seq)614 static inline void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
615 unsigned long *gp_seq)
616 {
617 *flags = 0;
618 *gp_seq = sp->srcu_idx;
619 }
620
621 #elif defined(CONFIG_TREE_SRCU)
622
623 void srcutorture_get_gp_data(struct srcu_struct *sp, int *flags,
624 unsigned long *gp_seq);
625
626 #endif
627
628 #ifdef CONFIG_TINY_RCU
rcu_watching_zero_in_eqs(int cpu,int * vp)629 static inline bool rcu_watching_zero_in_eqs(int cpu, int *vp) { return false; }
rcu_get_gp_seq(void)630 static inline unsigned long rcu_get_gp_seq(void) { return 0; }
rcu_exp_batches_completed(void)631 static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
rcu_force_quiescent_state(void)632 static inline void rcu_force_quiescent_state(void) { }
rcu_check_boost_fail(unsigned long gp_state,int * cpup)633 static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
show_rcu_gp_kthreads(void)634 static inline void show_rcu_gp_kthreads(void) { }
rcu_get_gp_kthreads_prio(void)635 static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
rcu_fwd_progress_check(unsigned long j)636 static inline void rcu_fwd_progress_check(unsigned long j) { }
rcu_gp_slow_register(atomic_t * rgssp)637 static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
rcu_gp_slow_unregister(atomic_t * rgssp)638 static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
639 #else /* #ifdef CONFIG_TINY_RCU */
640 bool rcu_watching_zero_in_eqs(int cpu, int *vp);
641 unsigned long rcu_get_gp_seq(void);
642 unsigned long rcu_exp_batches_completed(void);
643 bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
644 void show_rcu_gp_kthreads(void);
645 int rcu_get_gp_kthreads_prio(void);
646 void rcu_fwd_progress_check(unsigned long j);
647 void rcu_force_quiescent_state(void);
648 extern struct workqueue_struct *rcu_gp_wq;
649 extern struct kthread_worker *rcu_exp_gp_kworker;
650 void rcu_gp_slow_register(atomic_t *rgssp);
651 void rcu_gp_slow_unregister(atomic_t *rgssp);
652 #endif /* #else #ifdef CONFIG_TINY_RCU */
653
654 #ifdef CONFIG_TINY_SRCU
srcu_batches_completed(struct srcu_struct * sp)655 static inline unsigned long srcu_batches_completed(struct srcu_struct *sp) { return 0; }
656 #else // #ifdef CONFIG_TINY_SRCU
657 unsigned long srcu_batches_completed(struct srcu_struct *sp);
658 #endif // #else // #ifdef CONFIG_TINY_SRCU
659
660 #ifdef CONFIG_RCU_NOCB_CPU
661 void rcu_bind_current_to_nocb(void);
662 #else
rcu_bind_current_to_nocb(void)663 static inline void rcu_bind_current_to_nocb(void) { }
664 #endif
665
666 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
667 void show_rcu_tasks_classic_gp_kthread(void);
668 #else
show_rcu_tasks_classic_gp_kthread(void)669 static inline void show_rcu_tasks_classic_gp_kthread(void) {}
670 #endif
671 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
672 void show_rcu_tasks_rude_gp_kthread(void);
673 #else
show_rcu_tasks_rude_gp_kthread(void)674 static inline void show_rcu_tasks_rude_gp_kthread(void) {}
675 #endif
676 #if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_TRACE_RCU)
677 void show_rcu_tasks_trace_gp_kthread(void);
678 #else
show_rcu_tasks_trace_gp_kthread(void)679 static inline void show_rcu_tasks_trace_gp_kthread(void) {}
680 #endif
681
682 #ifdef CONFIG_TINY_RCU
rcu_cpu_beenfullyonline(int cpu)683 static inline bool rcu_cpu_beenfullyonline(int cpu) { return true; }
684 #else
685 bool rcu_cpu_beenfullyonline(int cpu);
686 #endif
687
688 #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
689 int rcu_stall_notifier_call_chain(unsigned long val, void *v);
690 #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
rcu_stall_notifier_call_chain(unsigned long val,void * v)691 static inline int rcu_stall_notifier_call_chain(unsigned long val, void *v) { return NOTIFY_DONE; }
692 #endif // #else // #if defined(CONFIG_RCU_STALL_COMMON) && defined(CONFIG_RCU_CPU_STALL_NOTIFIER)
693
694 #endif /* __LINUX_RCU_H */
695