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