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 */ 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 */ 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 */ 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. */ 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. */ 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. */ 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 */ 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. */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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; 231 232 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 } 242 243 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 */ 251 static inline int debug_rcu_head_queue(struct rcu_head *head) 252 { 253 return 0; 254 } 255 256 static inline void debug_rcu_head_unqueue(struct rcu_head *head) 257 { 258 } 259 #endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 260 261 static inline void debug_rcu_head_callback(struct rcu_head *rhp) 262 { 263 if (unlikely(!rhp->func)) 264 kmem_dump_obj(rhp); 265 } 266 267 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; 273 274 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); 291 292 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 */ 310 311 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 */ 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. */ 512 static inline bool rcu_gp_is_normal(void) { return true; } 513 static inline bool rcu_gp_is_expedited(void) { return false; } 514 static inline bool rcu_async_should_hurry(void) { return false; } 515 static inline void rcu_expedite_gp(void) { } 516 static inline void rcu_unexpedite_gp(void) { } 517 static inline void rcu_async_hurry(void) { } 518 static inline void rcu_async_relax(void) { } 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 */ 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 */ 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 575 static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; } 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 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 605 static inline void rcu_gp_set_torture_wait(int duration) { } 606 static inline void rcu_set_gpwrap_lag(unsigned long lag) { } 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 613 614 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 629 static inline bool rcu_watching_zero_in_eqs(int cpu, int *vp) { return false; } 630 static inline unsigned long rcu_get_gp_seq(void) { return 0; } 631 static inline unsigned long rcu_exp_batches_completed(void) { return 0; } 632 static inline void rcu_force_quiescent_state(void) { } 633 static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; } 634 static inline void show_rcu_gp_kthreads(void) { } 635 static inline int rcu_get_gp_kthreads_prio(void) { return 0; } 636 static inline void rcu_fwd_progress_check(unsigned long j) { } 637 static inline void rcu_gp_slow_register(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 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 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 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 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 679 static inline void show_rcu_tasks_trace_gp_kthread(void) {} 680 #endif 681 682 #ifdef CONFIG_TINY_RCU 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) 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