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