Lines Matching +full:i +full:- +full:leak +full:- +full:current
1 // SPDX-License-Identifier: GPL-2.0+
3 * Sleepable Read-Copy Update mechanism for mutual exclusion.
11 * For detailed explanation of Read-Copy Update mechanism see -
33 /* Holdoff in nanoseconds for auto-expediting. */
38 /* Overflow-check frequency. N bits roughly says every 2**N grace periods. */
63 /* Number of CPUs to trigger init_srcu_struct()-time transition to big. */
71 /* Early-boot callback-management, so early that no lock is required! */
117 * Initialize SRCU per-CPU data. Note that statically allocated
120 * is set, don't initialize ->srcu_lock_count[] and ->srcu_unlock_count[].
128 * Initialize the per-CPU srcu_data array, which feeds into the in init_srcu_struct_data()
131 WARN_ON_ONCE(ARRAY_SIZE(sdp->srcu_lock_count) != in init_srcu_struct_data()
132 ARRAY_SIZE(sdp->srcu_unlock_count)); in init_srcu_struct_data()
134 sdp = per_cpu_ptr(ssp->sda, cpu); in init_srcu_struct_data()
136 rcu_segcblist_init(&sdp->srcu_cblist); in init_srcu_struct_data()
137 sdp->srcu_cblist_invoking = false; in init_srcu_struct_data()
138 sdp->srcu_gp_seq_needed = ssp->srcu_sup->srcu_gp_seq; in init_srcu_struct_data()
139 sdp->srcu_gp_seq_needed_exp = ssp->srcu_sup->srcu_gp_seq; in init_srcu_struct_data()
140 sdp->mynode = NULL; in init_srcu_struct_data()
141 sdp->cpu = cpu; in init_srcu_struct_data()
142 INIT_WORK(&sdp->work, srcu_invoke_callbacks); in init_srcu_struct_data()
143 timer_setup(&sdp->delay_work, srcu_delay_timer, 0); in init_srcu_struct_data()
144 sdp->ssp = ssp; in init_srcu_struct_data()
167 int i; in init_srcu_struct_nodes() local
176 ssp->srcu_sup->node = kcalloc(rcu_num_nodes, sizeof(*ssp->srcu_sup->node), gfp_flags); in init_srcu_struct_nodes()
177 if (!ssp->srcu_sup->node) in init_srcu_struct_nodes()
181 ssp->srcu_sup->level[0] = &ssp->srcu_sup->node[0]; in init_srcu_struct_nodes()
182 for (i = 1; i < rcu_num_lvls; i++) in init_srcu_struct_nodes()
183 ssp->srcu_sup->level[i] = ssp->srcu_sup->level[i - 1] + num_rcu_lvl[i - 1]; in init_srcu_struct_nodes()
189 WARN_ON_ONCE(ARRAY_SIZE(snp->srcu_have_cbs) != in init_srcu_struct_nodes()
190 ARRAY_SIZE(snp->srcu_data_have_cbs)); in init_srcu_struct_nodes()
191 for (i = 0; i < ARRAY_SIZE(snp->srcu_have_cbs); i++) { in init_srcu_struct_nodes()
192 snp->srcu_have_cbs[i] = SRCU_SNP_INIT_SEQ; in init_srcu_struct_nodes()
193 snp->srcu_data_have_cbs[i] = 0; in init_srcu_struct_nodes()
195 snp->srcu_gp_seq_needed_exp = SRCU_SNP_INIT_SEQ; in init_srcu_struct_nodes()
196 snp->grplo = -1; in init_srcu_struct_nodes()
197 snp->grphi = -1; in init_srcu_struct_nodes()
198 if (snp == &ssp->srcu_sup->node[0]) { in init_srcu_struct_nodes()
200 snp->srcu_parent = NULL; in init_srcu_struct_nodes()
204 /* Non-root node. */ in init_srcu_struct_nodes()
205 if (snp == ssp->srcu_sup->level[level + 1]) in init_srcu_struct_nodes()
207 snp->srcu_parent = ssp->srcu_sup->level[level - 1] + in init_srcu_struct_nodes()
208 (snp - ssp->srcu_sup->level[level]) / in init_srcu_struct_nodes()
209 levelspread[level - 1]; in init_srcu_struct_nodes()
213 * Initialize the per-CPU srcu_data array, which feeds into the in init_srcu_struct_nodes()
216 level = rcu_num_lvls - 1; in init_srcu_struct_nodes()
217 snp_first = ssp->srcu_sup->level[level]; in init_srcu_struct_nodes()
219 sdp = per_cpu_ptr(ssp->sda, cpu); in init_srcu_struct_nodes()
220 sdp->mynode = &snp_first[cpu / levelspread[level]]; in init_srcu_struct_nodes()
221 for (snp = sdp->mynode; snp != NULL; snp = snp->srcu_parent) { in init_srcu_struct_nodes()
222 if (snp->grplo < 0) in init_srcu_struct_nodes()
223 snp->grplo = cpu; in init_srcu_struct_nodes()
224 snp->grphi = cpu; in init_srcu_struct_nodes()
226 sdp->grpmask = 1UL << (cpu - sdp->mynode->grplo); in init_srcu_struct_nodes()
228 smp_store_release(&ssp->srcu_sup->srcu_size_state, SRCU_SIZE_WAIT_BARRIER); in init_srcu_struct_nodes()
233 * Initialize non-compile-time initialized fields, including the
235 * tells us that ->sda has already been wired up to srcu_data.
240 ssp->srcu_sup = kzalloc(sizeof(*ssp->srcu_sup), GFP_KERNEL); in init_srcu_struct_fields()
241 if (!ssp->srcu_sup) in init_srcu_struct_fields()
242 return -ENOMEM; in init_srcu_struct_fields()
244 spin_lock_init(&ACCESS_PRIVATE(ssp->srcu_sup, lock)); in init_srcu_struct_fields()
245 ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL; in init_srcu_struct_fields()
246 ssp->srcu_sup->node = NULL; in init_srcu_struct_fields()
247 mutex_init(&ssp->srcu_sup->srcu_cb_mutex); in init_srcu_struct_fields()
248 mutex_init(&ssp->srcu_sup->srcu_gp_mutex); in init_srcu_struct_fields()
249 ssp->srcu_idx = 0; in init_srcu_struct_fields()
250 ssp->srcu_sup->srcu_gp_seq = 0; in init_srcu_struct_fields()
251 ssp->srcu_sup->srcu_barrier_seq = 0; in init_srcu_struct_fields()
252 mutex_init(&ssp->srcu_sup->srcu_barrier_mutex); in init_srcu_struct_fields()
253 atomic_set(&ssp->srcu_sup->srcu_barrier_cpu_cnt, 0); in init_srcu_struct_fields()
254 INIT_DELAYED_WORK(&ssp->srcu_sup->work, process_srcu); in init_srcu_struct_fields()
255 ssp->srcu_sup->sda_is_static = is_static; in init_srcu_struct_fields()
257 ssp->sda = alloc_percpu(struct srcu_data); in init_srcu_struct_fields()
258 if (!ssp->sda) in init_srcu_struct_fields()
261 ssp->srcu_sup->srcu_gp_seq_needed_exp = 0; in init_srcu_struct_fields()
262 ssp->srcu_sup->srcu_last_gp_end = ktime_get_mono_fast_ns(); in init_srcu_struct_fields()
263 if (READ_ONCE(ssp->srcu_sup->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) { in init_srcu_struct_fields()
266 WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG); in init_srcu_struct_fields()
268 ssp->srcu_sup->srcu_ssp = ssp; in init_srcu_struct_fields()
269 smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed, 0); /* Init done. */ in init_srcu_struct_fields()
274 free_percpu(ssp->sda); in init_srcu_struct_fields()
275 ssp->sda = NULL; in init_srcu_struct_fields()
279 kfree(ssp->srcu_sup); in init_srcu_struct_fields()
280 ssp->srcu_sup = NULL; in init_srcu_struct_fields()
282 return -ENOMEM; in init_srcu_struct_fields()
290 /* Don't re-initialize a lock while it is held. */ in __init_srcu_struct()
292 lockdep_init_map(&ssp->dep_map, name, key, 0); in __init_srcu_struct()
300 * init_srcu_struct - initialize a sleep-RCU structure
320 lockdep_assert_held(&ACCESS_PRIVATE(ssp->srcu_sup, lock)); in __srcu_transition_to_big()
321 smp_store_release(&ssp->srcu_sup->srcu_size_state, SRCU_SIZE_ALLOC); in __srcu_transition_to_big()
331 /* Double-checked locking on ->srcu_size-state. */ in srcu_transition_to_big()
332 if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL) in srcu_transition_to_big()
334 spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags); in srcu_transition_to_big()
335 if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL) { in srcu_transition_to_big()
336 spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags); in srcu_transition_to_big()
340 spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags); in srcu_transition_to_big()
344 * Check to see if the just-encountered contention event justifies
351 if (!SRCU_SIZING_IS_CONTEND() || ssp->srcu_sup->srcu_size_state) in spin_lock_irqsave_check_contention()
354 if (ssp->srcu_sup->srcu_size_jiffies != j) { in spin_lock_irqsave_check_contention()
355 ssp->srcu_sup->srcu_size_jiffies = j; in spin_lock_irqsave_check_contention()
356 ssp->srcu_sup->srcu_n_lock_retries = 0; in spin_lock_irqsave_check_contention()
358 if (++ssp->srcu_sup->srcu_n_lock_retries <= small_contention_lim) in spin_lock_irqsave_check_contention()
364 * Acquire the specified srcu_data structure's ->lock, but check for
371 struct srcu_struct *ssp = sdp->ssp; in spin_lock_irqsave_sdp_contention()
375 spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags); in spin_lock_irqsave_sdp_contention()
377 spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, *flags); in spin_lock_irqsave_sdp_contention()
382 * Acquire the specified srcu_struct structure's ->lock, but check for
389 if (spin_trylock_irqsave_rcu_node(ssp->srcu_sup, *flags)) in spin_lock_irqsave_ssp_contention()
391 spin_lock_irqsave_rcu_node(ssp->srcu_sup, *flags); in spin_lock_irqsave_ssp_contention()
396 * First-use initialization of statically allocated srcu_struct
398 * done with compile-time initialization, so this check is added
399 * to each update-side SRCU primitive. Use ssp->lock, which -is-
400 * compile-time initialized, to resolve races involving multiple
401 * CPUs trying to garner first-use privileges.
408 if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed))) /*^^^*/ in check_init_srcu_struct()
410 spin_lock_irqsave_rcu_node(ssp->srcu_sup, flags); in check_init_srcu_struct()
411 if (!rcu_seq_state(ssp->srcu_sup->srcu_gp_seq_needed)) { in check_init_srcu_struct()
412 spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags); in check_init_srcu_struct()
416 spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags); in check_init_srcu_struct()
420 * Returns approximate total of the readers' ->srcu_lock_count[] values
421 * for the rank of per-CPU counters specified by idx.
429 struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu); in srcu_readers_lock_idx()
431 sum += atomic_long_read(&cpuc->srcu_lock_count[idx]); in srcu_readers_lock_idx()
437 * Returns approximate total of the readers' ->srcu_unlock_count[] values
438 * for the rank of per-CPU counters specified by idx.
447 struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu); in srcu_readers_unlock_idx()
449 sum += atomic_long_read(&cpuc->srcu_unlock_count[idx]); in srcu_readers_unlock_idx()
451 mask = mask | READ_ONCE(cpuc->srcu_nmi_safety); in srcu_readers_unlock_idx()
454 "Mixed NMI-safe readers for srcu_struct at %ps.\n", ssp); in srcu_readers_unlock_idx()
459 * Return true if the number of pre-existing readers is determined to
485 * the current ->srcu_idx but not yet have incremented its CPU's in srcu_readers_active_idx_check()
486 * ->srcu_lock_count[idx] counter. In fact, it is possible in srcu_readers_active_idx_check()
488 * ->srcu_idx and incrementing ->srcu_lock_count[idx]. And there in srcu_readers_active_idx_check()
494 * code for a long time. That now-preempted updater has already in srcu_readers_active_idx_check()
495 * flipped ->srcu_idx (possibly during the preceding grace period), in srcu_readers_active_idx_check()
497 * period), and summed up the ->srcu_unlock_count[idx] counters. in srcu_readers_active_idx_check()
499 * increment the old ->srcu_idx value's ->srcu_lock_count[idx] in srcu_readers_active_idx_check()
503 * the old value of ->srcu_idx and is just about to use that value in srcu_readers_active_idx_check()
504 * to index its increment of ->srcu_lock_count[idx]. But as soon as in srcu_readers_active_idx_check()
505 * it leaves that SRCU read-side critical section, it will increment in srcu_readers_active_idx_check()
506 * ->srcu_unlock_count[idx], which must follow the updater's above in srcu_readers_active_idx_check()
508 * an smp_mb() and a later fetch from ->srcu_idx, that task will be in srcu_readers_active_idx_check()
510 * ->srcu_unlock_count[idx] in __srcu_read_unlock() is after the in srcu_readers_active_idx_check()
511 * smp_mb(), and the fetch from ->srcu_idx in __srcu_read_lock() in srcu_readers_active_idx_check()
513 * value of ->srcu_idx until the -second- __srcu_read_lock(), in srcu_readers_active_idx_check()
515 * ->srcu_lock_count[idx] for the old value of ->srcu_idx twice, in srcu_readers_active_idx_check()
523 * ->srcu_lock_count[idx] for the old index, where Nc is the number in srcu_readers_active_idx_check()
525 * structure limits the value of Nt and current systems limit Nc in srcu_readers_active_idx_check()
533 * comfortably beyond excessive. Especially on 64-bit systems, in srcu_readers_active_idx_check()
541 * srcu_readers_active - returns true if there are readers. and false
555 struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu); in srcu_readers_active()
557 sum += atomic_long_read(&cpuc->srcu_lock_count[0]); in srcu_readers_active()
558 sum += atomic_long_read(&cpuc->srcu_lock_count[1]); in srcu_readers_active()
559 sum -= atomic_long_read(&cpuc->srcu_unlock_count[0]); in srcu_readers_active()
560 sum -= atomic_long_read(&cpuc->srcu_unlock_count[1]); in srcu_readers_active()
569 * their read-side critical sections. If there are still some readers
571 * The blocking time is increased as the grace-period age increases,
582 #define SRCU_DEFAULT_MAX_NODELAY_PHASE_LO 3UL // Lowmark on default per-GP-phase
583 // no-delay instances.
584 #define SRCU_DEFAULT_MAX_NODELAY_PHASE_HI 1000UL // Highmark on default per-GP-phase
585 // no-delay instances.
590 // per-GP-phase no-delay instances adjusted to allow non-sleeping poll upto
596 // Maximum per-GP-phase consecutive no-delay instances.
605 // Maximum consecutive no-delay instances.
613 * Return grace-period delay, zero if there are expedited grace
621 struct srcu_usage *sup = ssp->srcu_sup; in srcu_get_delay()
623 if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp))) in srcu_get_delay()
625 if (rcu_seq_state(READ_ONCE(sup->srcu_gp_seq))) { in srcu_get_delay()
626 j = jiffies - 1; in srcu_get_delay()
627 gpstart = READ_ONCE(sup->srcu_gp_start); in srcu_get_delay()
629 jbase += j - gpstart; in srcu_get_delay()
631 WRITE_ONCE(sup->srcu_n_exp_nodelay, READ_ONCE(sup->srcu_n_exp_nodelay) + 1); in srcu_get_delay()
632 if (READ_ONCE(sup->srcu_n_exp_nodelay) > srcu_max_nodelay_phase) in srcu_get_delay()
640 * cleanup_srcu_struct - deconstruct a sleep-RCU structure
644 * was initialized via init_srcu_struct(), else you leak memory.
649 struct srcu_usage *sup = ssp->srcu_sup; in cleanup_srcu_struct()
652 return; /* Just leak it! */ in cleanup_srcu_struct()
654 return; /* Just leak it! */ in cleanup_srcu_struct()
655 flush_delayed_work(&sup->work); in cleanup_srcu_struct()
657 struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu); in cleanup_srcu_struct()
659 del_timer_sync(&sdp->delay_work); in cleanup_srcu_struct()
660 flush_work(&sdp->work); in cleanup_srcu_struct()
661 if (WARN_ON(rcu_segcblist_n_cbs(&sdp->srcu_cblist))) in cleanup_srcu_struct()
662 return; /* Forgot srcu_barrier(), so just leak it! */ in cleanup_srcu_struct()
664 if (WARN_ON(rcu_seq_state(READ_ONCE(sup->srcu_gp_seq)) != SRCU_STATE_IDLE) || in cleanup_srcu_struct()
665 WARN_ON(rcu_seq_current(&sup->srcu_gp_seq) != sup->srcu_gp_seq_needed) || in cleanup_srcu_struct()
668 __func__, ssp, rcu_seq_state(READ_ONCE(sup->srcu_gp_seq)), in cleanup_srcu_struct()
669 rcu_seq_current(&sup->srcu_gp_seq), sup->srcu_gp_seq_needed); in cleanup_srcu_struct()
672 kfree(sup->node); in cleanup_srcu_struct()
673 sup->node = NULL; in cleanup_srcu_struct()
674 sup->srcu_size_state = SRCU_SIZE_SMALL; in cleanup_srcu_struct()
675 if (!sup->sda_is_static) { in cleanup_srcu_struct()
676 free_percpu(ssp->sda); in cleanup_srcu_struct()
677 ssp->sda = NULL; in cleanup_srcu_struct()
679 ssp->srcu_sup = NULL; in cleanup_srcu_struct()
694 /* NMI-unsafe use in NMI is a bad sign */ in srcu_check_nmi_safety()
696 sdp = raw_cpu_ptr(ssp->sda); in srcu_check_nmi_safety()
697 old_nmi_safe_mask = READ_ONCE(sdp->srcu_nmi_safety); in srcu_check_nmi_safety()
699 WRITE_ONCE(sdp->srcu_nmi_safety, nmi_safe_mask); in srcu_check_nmi_safety()
702 …WARN_ONCE(old_nmi_safe_mask != nmi_safe_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_… in srcu_check_nmi_safety()
708 * Counts the new reader in the appropriate per-CPU element of the
716 idx = READ_ONCE(ssp->srcu_idx) & 0x1; in __srcu_read_lock()
717 this_cpu_inc(ssp->sda->srcu_lock_count[idx].counter); in __srcu_read_lock()
724 * Removes the count for the old reader from the appropriate per-CPU
731 this_cpu_inc(ssp->sda->srcu_unlock_count[idx].counter); in __srcu_read_unlock()
738 * Counts the new reader in the appropriate per-CPU element of the
739 * srcu_struct, but in an NMI-safe manner using RMW atomics.
745 struct srcu_data *sdp = raw_cpu_ptr(ssp->sda); in __srcu_read_lock_nmisafe()
747 idx = READ_ONCE(ssp->srcu_idx) & 0x1; in __srcu_read_lock_nmisafe()
748 atomic_long_inc(&sdp->srcu_lock_count[idx]); in __srcu_read_lock_nmisafe()
755 * Removes the count for the old reader from the appropriate per-CPU
761 struct srcu_data *sdp = raw_cpu_ptr(ssp->sda); in __srcu_read_unlock_nmisafe()
764 atomic_long_inc(&sdp->srcu_unlock_count[idx]); in __srcu_read_unlock_nmisafe()
777 lockdep_assert_held(&ACCESS_PRIVATE(ssp->srcu_sup, lock)); in srcu_gp_start()
778 WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)); in srcu_gp_start()
779 WRITE_ONCE(ssp->srcu_sup->srcu_gp_start, jiffies); in srcu_gp_start()
780 WRITE_ONCE(ssp->srcu_sup->srcu_n_exp_nodelay, 0); in srcu_gp_start()
781 smp_mb(); /* Order prior store to ->srcu_gp_seq_needed vs. GP start. */ in srcu_gp_start()
782 rcu_seq_start(&ssp->srcu_sup->srcu_gp_seq); in srcu_gp_start()
783 state = rcu_seq_state(ssp->srcu_sup->srcu_gp_seq); in srcu_gp_start()
792 queue_work_on(sdp->cpu, rcu_gp_wq, &sdp->work); in srcu_delay_timer()
799 queue_work_on(sdp->cpu, rcu_gp_wq, &sdp->work); in srcu_queue_delayed_work_on()
803 timer_reduce(&sdp->delay_work, jiffies + delay); in srcu_queue_delayed_work_on()
818 * just-completed grace period, the one corresponding to idx. If possible,
826 for (cpu = snp->grplo; cpu <= snp->grphi; cpu++) { in srcu_schedule_cbs_snp()
827 if (!(mask & (1UL << (cpu - snp->grplo)))) in srcu_schedule_cbs_snp()
829 srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, cpu), delay); in srcu_schedule_cbs_snp()
837 * The ->srcu_cb_mutex acquisition does not protect any data, but
839 * are initiating callback invocation. This allows the ->srcu_have_cbs[]
856 struct srcu_usage *sup = ssp->srcu_sup; in srcu_gp_end()
859 mutex_lock(&sup->srcu_cb_mutex); in srcu_gp_end()
861 /* End the current grace period. */ in srcu_gp_end()
863 idx = rcu_seq_state(sup->srcu_gp_seq); in srcu_gp_end()
865 if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp))) in srcu_gp_end()
868 WRITE_ONCE(sup->srcu_last_gp_end, ktime_get_mono_fast_ns()); in srcu_gp_end()
869 rcu_seq_end(&sup->srcu_gp_seq); in srcu_gp_end()
870 gpseq = rcu_seq_current(&sup->srcu_gp_seq); in srcu_gp_end()
871 if (ULONG_CMP_LT(sup->srcu_gp_seq_needed_exp, gpseq)) in srcu_gp_end()
872 WRITE_ONCE(sup->srcu_gp_seq_needed_exp, gpseq); in srcu_gp_end()
874 mutex_unlock(&sup->srcu_gp_mutex); in srcu_gp_end()
878 ss_state = smp_load_acquire(&sup->srcu_size_state); in srcu_gp_end()
880 srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, get_boot_cpu_id()), in srcu_gp_end()
883 idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs); in srcu_gp_end()
887 last_lvl = snp >= sup->level[rcu_num_lvls - 1]; in srcu_gp_end()
889 cbs = ss_state < SRCU_SIZE_BIG || snp->srcu_have_cbs[idx] == gpseq; in srcu_gp_end()
890 snp->srcu_have_cbs[idx] = gpseq; in srcu_gp_end()
891 rcu_seq_set_state(&snp->srcu_have_cbs[idx], 1); in srcu_gp_end()
892 sgsne = snp->srcu_gp_seq_needed_exp; in srcu_gp_end()
894 WRITE_ONCE(snp->srcu_gp_seq_needed_exp, gpseq); in srcu_gp_end()
898 mask = snp->srcu_data_have_cbs[idx]; in srcu_gp_end()
899 snp->srcu_data_have_cbs[idx] = 0; in srcu_gp_end()
909 sdp = per_cpu_ptr(ssp->sda, cpu); in srcu_gp_end()
911 if (ULONG_CMP_GE(gpseq, sdp->srcu_gp_seq_needed + 100)) in srcu_gp_end()
912 sdp->srcu_gp_seq_needed = gpseq; in srcu_gp_end()
913 if (ULONG_CMP_GE(gpseq, sdp->srcu_gp_seq_needed_exp + 100)) in srcu_gp_end()
914 sdp->srcu_gp_seq_needed_exp = gpseq; in srcu_gp_end()
919 mutex_unlock(&sup->srcu_cb_mutex); in srcu_gp_end()
923 gpseq = rcu_seq_current(&sup->srcu_gp_seq); in srcu_gp_end()
925 ULONG_CMP_LT(gpseq, sup->srcu_gp_seq_needed)) { in srcu_gp_end()
938 smp_store_release(&sup->srcu_size_state, ss_state + 1); in srcu_gp_end()
943 * Funnel-locking scheme to scalably mediate many concurrent expedited
944 * grace-period requests. This function is invoked for the first known
956 for (; snp != NULL; snp = snp->srcu_parent) { in srcu_funnel_exp_start()
957 sgsne = READ_ONCE(snp->srcu_gp_seq_needed_exp); in srcu_funnel_exp_start()
958 if (WARN_ON_ONCE(rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, s)) || in srcu_funnel_exp_start()
962 sgsne = snp->srcu_gp_seq_needed_exp; in srcu_funnel_exp_start()
967 WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s); in srcu_funnel_exp_start()
971 if (ULONG_CMP_LT(ssp->srcu_sup->srcu_gp_seq_needed_exp, s)) in srcu_funnel_exp_start()
972 WRITE_ONCE(ssp->srcu_sup->srcu_gp_seq_needed_exp, s); in srcu_funnel_exp_start()
973 spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags); in srcu_funnel_exp_start()
977 * Funnel-locking scheme to scalably mediate many concurrent grace-period
979 * period s. Losers must either ensure that their desired grace-period
993 int idx = rcu_seq_ctr(s) % ARRAY_SIZE(sdp->mynode->srcu_have_cbs); in srcu_funnel_gp_start()
998 struct srcu_usage *sup = ssp->srcu_sup; in srcu_funnel_gp_start()
1001 if (smp_load_acquire(&sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) in srcu_funnel_gp_start()
1004 snp_leaf = sdp->mynode; in srcu_funnel_gp_start()
1008 for (snp = snp_leaf; snp != NULL; snp = snp->srcu_parent) { in srcu_funnel_gp_start()
1009 if (WARN_ON_ONCE(rcu_seq_done(&sup->srcu_gp_seq, s)) && snp != snp_leaf) in srcu_funnel_gp_start()
1012 snp_seq = snp->srcu_have_cbs[idx]; in srcu_funnel_gp_start()
1015 snp->srcu_data_have_cbs[idx] |= sdp->grpmask; in srcu_funnel_gp_start()
1025 snp->srcu_have_cbs[idx] = s; in srcu_funnel_gp_start()
1027 snp->srcu_data_have_cbs[idx] |= sdp->grpmask; in srcu_funnel_gp_start()
1028 sgsne = snp->srcu_gp_seq_needed_exp; in srcu_funnel_gp_start()
1030 WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s); in srcu_funnel_gp_start()
1036 if (ULONG_CMP_LT(sup->srcu_gp_seq_needed, s)) { in srcu_funnel_gp_start()
1041 smp_store_release(&sup->srcu_gp_seq_needed, s); /*^^^*/ in srcu_funnel_gp_start()
1043 if (!do_norm && ULONG_CMP_LT(sup->srcu_gp_seq_needed_exp, s)) in srcu_funnel_gp_start()
1044 WRITE_ONCE(sup->srcu_gp_seq_needed_exp, s); in srcu_funnel_gp_start()
1047 if (!WARN_ON_ONCE(rcu_seq_done(&sup->srcu_gp_seq, s)) && in srcu_funnel_gp_start()
1048 rcu_seq_state(sup->srcu_gp_seq) == SRCU_STATE_IDLE) { in srcu_funnel_gp_start()
1049 WARN_ON_ONCE(ULONG_CMP_GE(sup->srcu_gp_seq, sup->srcu_gp_seq_needed)); in srcu_funnel_gp_start()
1058 queue_delayed_work(rcu_gp_wq, &sup->work, in srcu_funnel_gp_start()
1060 else if (list_empty(&sup->work.work.entry)) in srcu_funnel_gp_start()
1061 list_add(&sup->work.work.entry, &srcu_boot_list); in srcu_funnel_gp_start()
1069 * The caller must ensure that ->srcu_idx is not changed while checking.
1080 if ((--trycount + curdelay) <= 0) in try_check_zero()
1087 * Increment the ->srcu_idx counter so that future SRCU readers will
1088 * use the other rank of the ->srcu_(un)lock_count[] arrays. This allows
1089 * us to wait for pre-existing readers in a starvation-free manner.
1094 * Because the flip of ->srcu_idx is executed only if the in srcu_flip()
1096 * the ->srcu_unlock_count[] and ->srcu_lock_count[] sums matched in srcu_flip()
1101 * __srcu_read_lock(), that reader was using a value of ->srcu_idx in srcu_flip()
1106 * value of ->srcu_idx. in srcu_flip()
1108 * This sum-equality check and ordering also ensures that if in srcu_flip()
1110 * ->srcu_idx, this updater's earlier scans cannot have seen in srcu_flip()
1123 WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1); // Flip the counter. in srcu_flip()
1139 * Note that it is OK for several current from-idle requests for a new
1143 * Note also that if any CPU (including the current one) is still invoking
1150 * This function is also subject to counter-wrap errors, but let's face
1155 * of a needlessly non-expedited grace period is similarly negligible.
1167 sdp = raw_cpu_ptr(ssp->sda); in srcu_might_be_idle()
1169 if (rcu_segcblist_pend_cbs(&sdp->srcu_cblist)) { in srcu_might_be_idle()
1183 tlast = READ_ONCE(ssp->srcu_sup->srcu_last_gp_end); in srcu_might_be_idle()
1189 curseq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq); in srcu_might_be_idle()
1190 smp_mb(); /* Order ->srcu_gp_seq with ->srcu_gp_seq_needed. */ in srcu_might_be_idle()
1191 if (ULONG_CMP_LT(curseq, READ_ONCE(ssp->srcu_sup->srcu_gp_seq_needed))) in srcu_might_be_idle()
1193 smp_mb(); /* Order ->srcu_gp_seq with prior access. */ in srcu_might_be_idle()
1194 if (curseq != rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq)) in srcu_might_be_idle()
1200 * SRCU callback function to leak a callback.
1207 * Start an SRCU grace period, and also queue the callback if non-NULL.
1224 * SRCU read-side critical section so that the grace-period in srcu_gp_start_if_needed()
1228 ss_state = smp_load_acquire(&ssp->srcu_sup->srcu_size_state); in srcu_gp_start_if_needed()
1230 sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id()); in srcu_gp_start_if_needed()
1232 sdp = raw_cpu_ptr(ssp->sda); in srcu_gp_start_if_needed()
1235 rcu_segcblist_enqueue(&sdp->srcu_cblist, rhp); in srcu_gp_start_if_needed()
1238 * current gp sequence used for advancing, otherwise advancing may fail in srcu_gp_start_if_needed()
1263 s = rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq); in srcu_gp_start_if_needed()
1265 rcu_segcblist_advance(&sdp->srcu_cblist, in srcu_gp_start_if_needed()
1266 rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq)); in srcu_gp_start_if_needed()
1267 WARN_ON_ONCE(!rcu_segcblist_accelerate(&sdp->srcu_cblist, s)); in srcu_gp_start_if_needed()
1269 if (ULONG_CMP_LT(sdp->srcu_gp_seq_needed, s)) { in srcu_gp_start_if_needed()
1270 sdp->srcu_gp_seq_needed = s; in srcu_gp_start_if_needed()
1273 if (!do_norm && ULONG_CMP_LT(sdp->srcu_gp_seq_needed_exp, s)) { in srcu_gp_start_if_needed()
1274 sdp->srcu_gp_seq_needed_exp = s; in srcu_gp_start_if_needed()
1283 sdp_mynode = sdp->mynode; in srcu_gp_start_if_needed()
1295 * the current CPU and the specified srcu_struct structure, initiating
1296 * grace-period processing if it is not already running.
1299 * all pre-existing SRCU read-side critical section. On systems with
1302 * its last corresponding SRCU read-side critical section whose beginning
1304 * an SRCU read-side critical section that continues beyond the start of
1306 * but before the beginning of that SRCU read-side critical section.
1325 /* Probable double call_srcu(), so leak the callback. */ in __call_srcu()
1326 WRITE_ONCE(rhp->func, srcu_leak_callback); in __call_srcu()
1330 rhp->func = func; in __call_srcu()
1335 * call_srcu() - Queue a callback for invocation after an SRCU grace period
1341 * grace period elapses, in other words after all pre-existing SRCU
1342 * read-side critical sections have completed. However, the callback
1343 * function might well execute concurrently with other SRCU read-side
1345 * read-side critical sections are delimited by srcu_read_lock() and
1365 srcu_lock_sync(&ssp->dep_map); in __synchronize_srcu()
1371 "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section"); in __synchronize_srcu()
1387 * because the current CPU might have been totally uninvolved with in __synchronize_srcu()
1394 * synchronize_srcu_expedited - Brute-force SRCU grace period
1401 * memory-ordering properties as does synchronize_srcu().
1410 * synchronize_srcu - wait for prior SRCU read-side critical-section completion
1415 * the index=((->srcu_idx & 1) ^ 1) to drain to zero at first,
1421 * SRCU read-side critical section; doing so will result in deadlock.
1423 * srcu_struct from some other srcu_struct's read-side critical section,
1426 * There are memory-ordering constraints implied by synchronize_srcu().
1429 * the end of its last corresponding SRCU read-side critical section
1431 * each CPU having an SRCU read-side critical section that extends beyond
1434 * the beginning of that SRCU read-side critical section. Note that these
1444 * Of course, these memory-ordering guarantees apply only when
1448 * Implementation of these memory-ordering guarantees is similar to
1466 * get_state_synchronize_srcu - Provide an end-of-grace-period cookie
1477 // Any prior manipulation of SRCU-protected data must happen in get_state_synchronize_srcu()
1478 // before the load from ->srcu_gp_seq. in get_state_synchronize_srcu()
1480 return rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq); in get_state_synchronize_srcu()
1485 * start_poll_synchronize_srcu - Provide cookie and start grace period
1501 * poll_state_synchronize_srcu - Has cookie's grace period ended?
1511 * This is more pronounced on 32-bit systems where cookies are 32 bits,
1513 * 25-microsecond expedited SRCU grace periods. However, a more likely
1515 * one-millisecond SRCU grace periods. Of course, wrapping in a 64-bit
1521 * a 16-bit cookie, which rcutorture routinely wraps in a matter of a
1527 if (!rcu_seq_done(&ssp->srcu_sup->srcu_gp_seq, cookie)) in poll_state_synchronize_srcu()
1545 ssp = sdp->ssp; in srcu_barrier_cb()
1546 if (atomic_dec_and_test(&ssp->srcu_sup->srcu_barrier_cpu_cnt)) in srcu_barrier_cb()
1547 complete(&ssp->srcu_sup->srcu_barrier_completion); in srcu_barrier_cb()
1552 * structure's ->cblist. but only if that ->cblist already has at least one
1561 atomic_inc(&ssp->srcu_sup->srcu_barrier_cpu_cnt); in srcu_barrier_one_cpu()
1562 sdp->srcu_barrier_head.func = srcu_barrier_cb; in srcu_barrier_one_cpu()
1563 debug_rcu_head_queue(&sdp->srcu_barrier_head); in srcu_barrier_one_cpu()
1564 if (!rcu_segcblist_entrain(&sdp->srcu_cblist, in srcu_barrier_one_cpu()
1565 &sdp->srcu_barrier_head)) { in srcu_barrier_one_cpu()
1566 debug_rcu_head_unqueue(&sdp->srcu_barrier_head); in srcu_barrier_one_cpu()
1567 atomic_dec(&ssp->srcu_sup->srcu_barrier_cpu_cnt); in srcu_barrier_one_cpu()
1573 * srcu_barrier - Wait until all in-flight call_srcu() callbacks complete.
1574 * @ssp: srcu_struct on which to wait for in-flight callbacks.
1580 unsigned long s = rcu_seq_snap(&ssp->srcu_sup->srcu_barrier_seq); in srcu_barrier()
1583 mutex_lock(&ssp->srcu_sup->srcu_barrier_mutex); in srcu_barrier()
1584 if (rcu_seq_done(&ssp->srcu_sup->srcu_barrier_seq, s)) { in srcu_barrier()
1586 mutex_unlock(&ssp->srcu_sup->srcu_barrier_mutex); in srcu_barrier()
1589 rcu_seq_start(&ssp->srcu_sup->srcu_barrier_seq); in srcu_barrier()
1590 init_completion(&ssp->srcu_sup->srcu_barrier_completion); in srcu_barrier()
1593 atomic_set(&ssp->srcu_sup->srcu_barrier_cpu_cnt, 1); in srcu_barrier()
1596 if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) in srcu_barrier()
1597 srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, get_boot_cpu_id())); in srcu_barrier()
1600 srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, cpu)); in srcu_barrier()
1604 if (atomic_dec_and_test(&ssp->srcu_sup->srcu_barrier_cpu_cnt)) in srcu_barrier()
1605 complete(&ssp->srcu_sup->srcu_barrier_completion); in srcu_barrier()
1606 wait_for_completion(&ssp->srcu_sup->srcu_barrier_completion); in srcu_barrier()
1608 rcu_seq_end(&ssp->srcu_sup->srcu_barrier_seq); in srcu_barrier()
1609 mutex_unlock(&ssp->srcu_sup->srcu_barrier_mutex); in srcu_barrier()
1614 * srcu_batches_completed - return batches completed.
1622 return READ_ONCE(ssp->srcu_idx); in srcu_batches_completed()
1627 * Core SRCU state machine. Push state bits of ->srcu_gp_seq
1635 mutex_lock(&ssp->srcu_sup->srcu_gp_mutex); in srcu_advance_state()
1639 * fetching ->srcu_idx for their index, at any point in time there in srcu_advance_state()
1644 * The load-acquire ensures that we see the accesses performed in srcu_advance_state()
1647 idx = rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq)); /* ^^^ */ in srcu_advance_state()
1649 spin_lock_irq_rcu_node(ssp->srcu_sup); in srcu_advance_state()
1650 if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) { in srcu_advance_state()
1651 WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq)); in srcu_advance_state()
1652 spin_unlock_irq_rcu_node(ssp->srcu_sup); in srcu_advance_state()
1653 mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex); in srcu_advance_state()
1656 idx = rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)); in srcu_advance_state()
1659 spin_unlock_irq_rcu_node(ssp->srcu_sup); in srcu_advance_state()
1661 mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex); in srcu_advance_state()
1666 if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) == SRCU_STATE_SCAN1) { in srcu_advance_state()
1667 idx = 1 ^ (ssp->srcu_idx & 1); in srcu_advance_state()
1669 mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex); in srcu_advance_state()
1673 spin_lock_irq_rcu_node(ssp->srcu_sup); in srcu_advance_state()
1674 rcu_seq_set_state(&ssp->srcu_sup->srcu_gp_seq, SRCU_STATE_SCAN2); in srcu_advance_state()
1675 ssp->srcu_sup->srcu_n_exp_nodelay = 0; in srcu_advance_state()
1676 spin_unlock_irq_rcu_node(ssp->srcu_sup); in srcu_advance_state()
1679 if (rcu_seq_state(READ_ONCE(ssp->srcu_sup->srcu_gp_seq)) == SRCU_STATE_SCAN2) { in srcu_advance_state()
1682 * SRCU read-side critical sections are normally short, in srcu_advance_state()
1685 idx = 1 ^ (ssp->srcu_idx & 1); in srcu_advance_state()
1687 mutex_unlock(&ssp->srcu_sup->srcu_gp_mutex); in srcu_advance_state()
1690 ssp->srcu_sup->srcu_n_exp_nodelay = 0; in srcu_advance_state()
1691 srcu_gp_end(ssp); /* Releases ->srcu_gp_mutex. */ in srcu_advance_state()
1712 ssp = sdp->ssp; in srcu_invoke_callbacks()
1715 WARN_ON_ONCE(!rcu_segcblist_segempty(&sdp->srcu_cblist, RCU_NEXT_TAIL)); in srcu_invoke_callbacks()
1716 rcu_segcblist_advance(&sdp->srcu_cblist, in srcu_invoke_callbacks()
1717 rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq)); in srcu_invoke_callbacks()
1719 * Although this function is theoretically re-entrant, concurrent in srcu_invoke_callbacks()
1723 if (sdp->srcu_cblist_invoking || in srcu_invoke_callbacks()
1724 !rcu_segcblist_ready_cbs(&sdp->srcu_cblist)) { in srcu_invoke_callbacks()
1730 sdp->srcu_cblist_invoking = true; in srcu_invoke_callbacks()
1731 rcu_segcblist_extract_done_cbs(&sdp->srcu_cblist, &ready_cbs); in srcu_invoke_callbacks()
1739 rhp->func(rhp); in srcu_invoke_callbacks()
1749 rcu_segcblist_add_len(&sdp->srcu_cblist, -len); in srcu_invoke_callbacks()
1750 sdp->srcu_cblist_invoking = false; in srcu_invoke_callbacks()
1751 more = rcu_segcblist_ready_cbs(&sdp->srcu_cblist); in srcu_invoke_callbacks()
1760 * more SRCU callbacks queued, otherwise put SRCU into not-running state.
1766 spin_lock_irq_rcu_node(ssp->srcu_sup); in srcu_reschedule()
1767 if (ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed)) { in srcu_reschedule()
1768 if (!WARN_ON_ONCE(rcu_seq_state(ssp->srcu_sup->srcu_gp_seq))) { in srcu_reschedule()
1772 } else if (!rcu_seq_state(ssp->srcu_sup->srcu_gp_seq)) { in srcu_reschedule()
1776 spin_unlock_irq_rcu_node(ssp->srcu_sup); in srcu_reschedule()
1779 queue_delayed_work(rcu_gp_wq, &ssp->srcu_sup->work, delay); in srcu_reschedule()
1783 * This is the work-queue function that handles SRCU grace periods.
1793 ssp = sup->srcu_ssp; in process_srcu()
1798 WRITE_ONCE(sup->reschedule_count, 0); in process_srcu()
1801 if (READ_ONCE(sup->reschedule_jiffies) == j) { in process_srcu()
1802 WRITE_ONCE(sup->reschedule_count, READ_ONCE(sup->reschedule_count) + 1); in process_srcu()
1803 if (READ_ONCE(sup->reschedule_count) > srcu_max_nodelay) in process_srcu()
1806 WRITE_ONCE(sup->reschedule_count, 1); in process_srcu()
1807 WRITE_ONCE(sup->reschedule_jiffies, j); in process_srcu()
1820 *gp_seq = rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq); in srcutorture_get_gp_data()
1842 int ss_state = READ_ONCE(ssp->srcu_sup->srcu_size_state); in srcu_torture_stats_print()
1845 idx = ssp->srcu_idx & 0x1; in srcu_torture_stats_print()
1847 ss_state_idx = ARRAY_SIZE(srcu_size_state_name) - 1; in srcu_torture_stats_print()
1849 tt, tf, rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq), ss_state, in srcu_torture_stats_print()
1851 if (!ssp->sda) { in srcu_torture_stats_print()
1853 pr_cont(" No per-CPU srcu_data structures (->sda == NULL).\n"); in srcu_torture_stats_print()
1855 pr_cont(" per-CPU(idx=%d):", idx); in srcu_torture_stats_print()
1862 sdp = per_cpu_ptr(ssp->sda, cpu); in srcu_torture_stats_print()
1863 u0 = data_race(atomic_long_read(&sdp->srcu_unlock_count[!idx])); in srcu_torture_stats_print()
1864 u1 = data_race(atomic_long_read(&sdp->srcu_unlock_count[idx])); in srcu_torture_stats_print()
1872 l0 = data_race(atomic_long_read(&sdp->srcu_lock_count[!idx])); in srcu_torture_stats_print()
1873 l1 = data_race(atomic_long_read(&sdp->srcu_lock_count[idx])); in srcu_torture_stats_print()
1875 c0 = l0 - u0; in srcu_torture_stats_print()
1876 c1 = l1 - u1; in srcu_torture_stats_print()
1879 "C."[rcu_segcblist_empty(&sdp->srcu_cblist)]); in srcu_torture_stats_print()
1894 pr_info("\tNon-default auto-expedite holdoff of %lu ns.\n", exp_holdoff); in srcu_bootup_announce()
1896 pr_info("\tNon-default retry check delay of %lu us.\n", srcu_retry_check_delay); in srcu_bootup_announce()
1898 pr_info("\tNon-default max no-delay of %lu.\n", srcu_max_nodelay); in srcu_bootup_announce()
1899 pr_info("\tMax phase no-delay instances is %lu.\n", srcu_max_nodelay_phase); in srcu_bootup_announce()
1908 /* Decide on srcu_struct-size strategy. */ in srcu_init()
1928 list_del_init(&sup->work.work.entry); in srcu_init()
1930 sup->srcu_size_state == SRCU_SIZE_SMALL) in srcu_init()
1931 sup->srcu_size_state = SRCU_SIZE_ALLOC; in srcu_init()
1932 queue_work(rcu_gp_wq, &sup->work.work); in srcu_init()
1938 /* Initialize any global-scope srcu_struct structures used by this module. */
1941 int i; in srcu_module_coming() local
1943 struct srcu_struct **sspp = mod->srcu_struct_ptrs; in srcu_module_coming()
1945 for (i = 0; i < mod->num_srcu_structs; i++) { in srcu_module_coming()
1947 ssp->sda = alloc_percpu(struct srcu_data); in srcu_module_coming()
1948 if (WARN_ON_ONCE(!ssp->sda)) in srcu_module_coming()
1949 return -ENOMEM; in srcu_module_coming()
1954 /* Clean up any global-scope srcu_struct structures used by this module. */
1957 int i; in srcu_module_going() local
1959 struct srcu_struct **sspp = mod->srcu_struct_ptrs; in srcu_module_going()
1961 for (i = 0; i < mod->num_srcu_structs; i++) { in srcu_module_going()
1963 if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed)) && in srcu_module_going()
1964 !WARN_ON_ONCE(!ssp->srcu_sup->sda_is_static)) in srcu_module_going()
1967 free_percpu(ssp->sda); in srcu_module_going()