diff options
| -rw-r--r-- | include/linux/rculist.h | 6 | ||||
| -rw-r--r-- | include/linux/rcupdate.h | 16 | ||||
| -rw-r--r-- | kernel/rcu/rcutorture.c | 2 | ||||
| -rw-r--r-- | kernel/rcu/srcu.c | 10 | ||||
| -rw-r--r-- | kernel/rcu/tiny_plugin.h | 12 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 184 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 93 | ||||
| -rw-r--r-- | kernel/rcu/tree_trace.c | 6 | ||||
| -rw-r--r-- | kernel/rcu/update.c | 30 | ||||
| -rw-r--r-- | kernel/torture.c | 26 |
10 files changed, 193 insertions, 192 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h index a18b16f1dc0e..665397247e82 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -29,8 +29,8 @@ */ static inline void INIT_LIST_HEAD_RCU(struct list_head *list) { - ACCESS_ONCE(list->next) = list; - ACCESS_ONCE(list->prev) = list; + WRITE_ONCE(list->next, list); + WRITE_ONCE(list->prev, list); } /* @@ -288,7 +288,7 @@ static inline void list_splice_init_rcu(struct list_head *list, #define list_first_or_null_rcu(ptr, type, member) \ ({ \ struct list_head *__ptr = (ptr); \ - struct list_head *__next = ACCESS_ONCE(__ptr->next); \ + struct list_head *__next = READ_ONCE(__ptr->next); \ likely(__ptr != __next) ? list_entry_rcu(__next, type, member) : NULL; \ }) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 573a5afd5ed8..87bb0eee665b 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -364,8 +364,8 @@ extern struct srcu_struct tasks_rcu_exit_srcu; #define rcu_note_voluntary_context_switch(t) \ do { \ rcu_all_qs(); \ - if (ACCESS_ONCE((t)->rcu_tasks_holdout)) \ - ACCESS_ONCE((t)->rcu_tasks_holdout) = false; \ + if (READ_ONCE((t)->rcu_tasks_holdout)) \ + WRITE_ONCE((t)->rcu_tasks_holdout, false); \ } while (0) #else /* #ifdef CONFIG_TASKS_RCU */ #define TASKS_RCU(x) do { } while (0) @@ -609,7 +609,7 @@ static inline void rcu_preempt_sleep_check(void) #define __rcu_access_pointer(p, space) \ ({ \ - typeof(*p) *_________p1 = (typeof(*p) *__force)ACCESS_ONCE(p); \ + typeof(*p) *_________p1 = (typeof(*p) *__force)READ_ONCE(p); \ rcu_dereference_sparse(p, space); \ ((typeof(*p) __force __kernel *)(_________p1)); \ }) @@ -630,7 +630,7 @@ static inline void rcu_preempt_sleep_check(void) #define __rcu_access_index(p, space) \ ({ \ - typeof(p) _________p1 = ACCESS_ONCE(p); \ + typeof(p) _________p1 = READ_ONCE(p); \ rcu_dereference_sparse(p, space); \ (_________p1); \ }) @@ -659,7 +659,7 @@ static inline void rcu_preempt_sleep_check(void) */ #define lockless_dereference(p) \ ({ \ - typeof(p) _________p1 = ACCESS_ONCE(p); \ + typeof(p) _________p1 = READ_ONCE(p); \ smp_read_barrier_depends(); /* Dependency order vs. p above. */ \ (_________p1); \ }) @@ -702,7 +702,7 @@ static inline void rcu_preempt_sleep_check(void) * @p: The pointer to read * * Return the value of the specified RCU-protected pointer, but omit the - * smp_read_barrier_depends() and keep the ACCESS_ONCE(). This is useful + * smp_read_barrier_depends() and keep the READ_ONCE(). This is useful * when the value of this pointer is accessed, but the pointer is not * dereferenced, for example, when testing an RCU-protected pointer against * NULL. Although rcu_access_pointer() may also be used in cases where @@ -791,7 +791,7 @@ static inline void rcu_preempt_sleep_check(void) * @p: The index to read * * Return the value of the specified RCU-protected index, but omit the - * smp_read_barrier_depends() and keep the ACCESS_ONCE(). This is useful + * smp_read_barrier_depends() and keep the READ_ONCE(). This is useful * when the value of this index is accessed, but the index is not * dereferenced, for example, when testing an RCU-protected index against * -1. Although rcu_access_index() may also be used in cases where @@ -827,7 +827,7 @@ static inline void rcu_preempt_sleep_check(void) * @c: The conditions under which the dereference will take place * * Return the value of the specified RCU-protected pointer, but omit - * both the smp_read_barrier_depends() and the ACCESS_ONCE(). This + * both the smp_read_barrier_depends() and the READ_ONCE(). This * is useful in cases where update-side locks prevent the value of the * pointer from changing. Please note that this primitive does -not- * prevent the compiler from repeating this reference or combining it diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 8dbe27611ec3..a67ef6ff86b0 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1413,7 +1413,7 @@ static int rcu_torture_barrier_cbs(void *arg) do { wait_event(barrier_cbs_wq[myid], (newphase = - ACCESS_ONCE(barrier_phase)) != lastphase || + READ_ONCE(barrier_phase)) != lastphase || torture_must_stop()); lastphase = newphase; smp_mb(); /* ensure barrier_phase load before ->call(). */ diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index cad76e76b4e7..fb33d35ee0b7 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -151,7 +151,7 @@ static unsigned long srcu_readers_seq_idx(struct srcu_struct *sp, int idx) unsigned long t; for_each_possible_cpu(cpu) { - t = ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->seq[idx]); + t = READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->seq[idx]); sum += t; } return sum; @@ -168,7 +168,7 @@ static unsigned long srcu_readers_active_idx(struct srcu_struct *sp, int idx) unsigned long t; for_each_possible_cpu(cpu) { - t = ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[idx]); + t = READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[idx]); sum += t; } return sum; @@ -265,8 +265,8 @@ static int srcu_readers_active(struct srcu_struct *sp) unsigned long sum = 0; for_each_possible_cpu(cpu) { - sum += ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[0]); - sum += ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[1]); + sum += READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[0]); + sum += READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[1]); } return sum; } @@ -296,7 +296,7 @@ int __srcu_read_lock(struct srcu_struct *sp) { int idx; - idx = ACCESS_ONCE(sp->completed) & 0x1; + idx = READ_ONCE(sp->completed) & 0x1; preempt_disable(); __this_cpu_inc(sp->per_cpu_ref->c[idx]); smp_mb(); /* B */ /* Avoid leaking the critical section. */ diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h index f94e209a10d6..e492a5253e0f 100644 --- a/kernel/rcu/tiny_plugin.h +++ b/kernel/rcu/tiny_plugin.h @@ -144,16 +144,17 @@ static void check_cpu_stall(struct rcu_ctrlblk *rcp) return; rcp->ticks_this_gp++; j = jiffies; - js = ACCESS_ONCE(rcp->jiffies_stall); + js = READ_ONCE(rcp->jiffies_stall); if (rcp->rcucblist && ULONG_CMP_GE(j, js)) { pr_err("INFO: %s stall on CPU (%lu ticks this GP) idle=%llx (t=%lu jiffies q=%ld)\n", rcp->name, rcp->ticks_this_gp, DYNTICK_TASK_EXIT_IDLE, jiffies - rcp->gp_start, rcp->qlen); dump_stack(); - ACCESS_ONCE(rcp->jiffies_stall) = jiffies + - 3 * rcu_jiffies_till_stall_check() + 3; + WRITE_ONCE(rcp->jiffies_stall, + jiffies + 3 * rcu_jiffies_till_stall_check() + 3); } else if (ULONG_CMP_GE(j, js)) { - ACCESS_ONCE(rcp->jiffies_stall) = jiffies + rcu_jiffies_till_stall_check(); + WRITE_ONCE(rcp->jiffies_stall, + jiffies + rcu_jiffies_till_stall_check()); } } @@ -161,7 +162,8 @@ static void reset_cpu_stall_ticks(struct rcu_ctrlblk *rcp) { rcp->ticks_this_gp = 0; rcp->gp_start = jiffies; - ACCESS_ONCE(rcp->jiffies_stall) = jiffies + rcu_jiffies_till_stall_check(); + WRITE_ONCE(rcp->jiffies_stall, + jiffies + rcu_jiffies_till_stall_check()); } static void check_cpu_stalls(void) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8cf7304b2867..0628df155970 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -191,17 +191,17 @@ unsigned long rcutorture_vernum; */ unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp) { - return ACCESS_ONCE(rnp->qsmaskinitnext); + return READ_ONCE(rnp->qsmaskinitnext); } /* - * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s + * Return true if an RCU grace period is in progress. The READ_ONCE()s * permit this function to be invoked without holding the root rcu_node * structure's ->lock, but of course results can be subject to change. */ static int rcu_gp_in_progress(struct rcu_state *rsp) { - return ACCESS_ONCE(rsp->completed) != ACCESS_ONCE(rsp->gpnum); + return READ_ONCE(rsp->completed) != READ_ONCE(rsp->gpnum); } /* @@ -278,8 +278,8 @@ static void rcu_momentary_dyntick_idle(void) if (!(resched_mask & rsp->flavor_mask)) continue; smp_mb(); /* rcu_sched_qs_mask before cond_resched_completed. */ - if (ACCESS_ONCE(rdp->mynode->completed) != - ACCESS_ONCE(rdp->cond_resched_completed)) + if (READ_ONCE(rdp->mynode->completed) != + READ_ONCE(rdp->cond_resched_completed)) continue; /* @@ -491,9 +491,9 @@ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags, break; } if (rsp != NULL) { - *flags = ACCESS_ONCE(rsp->gp_flags); - *gpnum = ACCESS_ONCE(rsp->gpnum); - *completed = ACCESS_ONCE(rsp->completed); + *flags = READ_ONCE(rsp->gp_flags); + *gpnum = READ_ONCE(rsp->gpnum); + *completed = READ_ONCE(rsp->completed); return; } *flags = 0; @@ -539,10 +539,10 @@ static struct rcu_node *rcu_get_root(struct rcu_state *rsp) static int rcu_future_needs_gp(struct rcu_state *rsp) { struct rcu_node *rnp = rcu_get_root(rsp); - int idx = (ACCESS_ONCE(rnp->completed) + 1) & 0x1; + int idx = (READ_ONCE(rnp->completed) + 1) & 0x1; int *fp = &rnp->need_future_gp[idx]; - return ACCESS_ONCE(*fp); + return READ_ONCE(*fp); } /* @@ -565,7 +565,7 @@ cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp) return 1; /* Yes, this CPU has newly registered callbacks. */ for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++) if (rdp->nxttail[i - 1] != rdp->nxttail[i] && - ULONG_CMP_LT(ACCESS_ONCE(rsp->completed), + ULONG_CMP_LT(READ_ONCE(rsp->completed), rdp->nxtcompleted[i])) return 1; /* Yes, CBs for future grace period. */ return 0; /* No grace period needed. */ @@ -1011,9 +1011,9 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp, trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti")); return 1; } else { - if (ULONG_CMP_LT(ACCESS_ONCE(rdp->gpnum) + ULONG_MAX / 4, + if (ULONG_CMP_LT(READ_ONCE(rdp->gpnum) + ULONG_MAX / 4, rdp->mynode->gpnum)) - ACCESS_ONCE(rdp->gpwrap) = true; + WRITE_ONCE(rdp->gpwrap, true); return 0; } } @@ -1093,12 +1093,12 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp, if (ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + jiffies_till_sched_qs) || ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) { - if (!(ACCESS_ONCE(*rcrmp) & rdp->rsp->flavor_mask)) { - ACCESS_ONCE(rdp->cond_resched_completed) = - ACCESS_ONCE(rdp->mynode->completed); + if (!(READ_ONCE(*rcrmp) & rdp->rsp->flavor_mask)) { + WRITE_ONCE(rdp->cond_resched_completed, + READ_ONCE(rdp->mynode->completed)); smp_mb(); /* ->cond_resched_completed before *rcrmp. */ - ACCESS_ONCE(*rcrmp) = - ACCESS_ONCE(*rcrmp) + rdp->rsp->flavor_mask; + WRITE_ONCE(*rcrmp, + READ_ONCE(*rcrmp) + rdp->rsp->flavor_mask); resched_cpu(rdp->cpu); /* Force CPU into scheduler. */ rdp->rsp->jiffies_resched += 5; /* Enable beating. */ } else if (ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) { @@ -1119,9 +1119,9 @@ static void record_gp_stall_check_time(struct rcu_state *rsp) rsp->gp_start = j; smp_wmb(); /* Record start time before stall time. */ j1 = rcu_jiffies_till_stall_check(); - ACCESS_ONCE(rsp->jiffies_stall) = j + j1; + WRITE_ONCE(rsp->jiffies_stall, j + j1); rsp->jiffies_resched = j + j1 / 2; - rsp->n_force_qs_gpstart = ACCESS_ONCE(rsp->n_force_qs); + rsp->n_force_qs_gpstart = READ_ONCE(rsp->n_force_qs); } /* @@ -1133,7 +1133,7 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp) unsigned long j; j = jiffies; - gpa = ACCESS_ONCE(rsp->gp_activity); + gpa = READ_ONCE(rsp->gp_activity); if (j - gpa > 2 * HZ) pr_err("%s kthread starved for %ld jiffies!\n", rsp->name, j - gpa); @@ -1173,12 +1173,13 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) /* Only let one CPU complain about others per time interval. */ raw_spin_lock_irqsave(&rnp->lock, flags); - delta = jiffies - ACCESS_ONCE(rsp->jiffies_stall); + delta = jiffies - READ_ONCE(rsp->jiffies_stall); if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } - ACCESS_ONCE(rsp->jiffies_stall) = jiffies + 3 * rcu_jiffies_till_stall_check() + 3; + WRITE_ONCE(rsp->jiffies_stall, + jiffies + 3 * rcu_jiffies_till_stall_check() + 3); raw_spin_unlock_irqrestore(&rnp->lock, flags); /* @@ -1212,12 +1213,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) if (ndetected) { rcu_dump_cpu_stacks(rsp); } else { - if (ACCESS_ONCE(rsp->gpnum) != gpnum || - ACCESS_ONCE(rsp->completed) == gpnum) { + if (READ_ONCE(rsp->gpnum) != gpnum || + READ_ONCE(rsp->completed) == gpnum) { pr_err("INFO: Stall ended before state dump start\n"); } else { j = jiffies; - gpa = ACCESS_ONCE(rsp->gp_activity); + gpa = READ_ONCE(rsp->gp_activity); pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n", rsp->name, j - gpa, j, gpa, jiffies_till_next_fqs, @@ -1262,9 +1263,9 @@ static void print_cpu_stall(struct rcu_state *rsp) rcu_dump_cpu_stacks(rsp); raw_spin_lock_irqsave(&rnp->lock, flags); - if (ULONG_CMP_GE(jiffies, ACCESS_ONCE(rsp->jiffies_stall))) - ACCESS_ONCE(rsp->jiffies_stall) = jiffies + - 3 * rcu_jiffies_till_stall_check() + 3; + if (ULONG_CMP_GE(jiffies, READ_ONCE(rsp->jiffies_stall))) + WRITE_ONCE(rsp->jiffies_stall, + jiffies + 3 * rcu_jiffies_till_stall_check() + 3); raw_spin_unlock_irqrestore(&rnp->lock, flags); /* @@ -1307,20 +1308,20 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) * Given this check, comparisons of jiffies, rsp->jiffies_stall, * and rsp->gp_start suffice to forestall false positives. */ - gpnum = ACCESS_ONCE(rsp->gpnum); + gpnum = READ_ONCE(rsp->gpnum); smp_rmb(); /* Pick up ->gpnum first... */ - js = ACCESS_ONCE(rsp->jiffies_stall); + js = READ_ONCE(rsp->jiffies_stall); smp_rmb(); /* ...then ->jiffies_stall before the rest... */ - gps = ACCESS_ONCE(rsp->gp_start); + gps = READ_ONCE(rsp->gp_start); smp_rmb(); /* ...and finally ->gp_start before ->completed. */ - completed = ACCESS_ONCE(rsp->completed); + completed = READ_ONCE(rsp->completed); if (ULONG_CMP_GE(completed, gpnum) || ULONG_CMP_LT(j, js) || ULONG_CMP_GE(gps, js)) return; /* No stall or GP completed since entering function. */ rnp = rdp->mynode; if (rcu_gp_in_progress(rsp) && - (ACCESS_ONCE(rnp->qsmask) & rdp->grpmask)) { + (READ_ONCE(rnp->qsmask) & rdp->grpmask)) { /* We haven't checked in, so go dump stack. */ print_cpu_stall(rsp); @@ -1347,7 +1348,7 @@ void rcu_cpu_stall_reset(void) struct rcu_state *rsp; for_each_rcu_flavor(rsp) - ACCESS_ONCE(rsp->jiffies_stall) = jiffies + ULONG_MAX / 2; + WRITE_ONCE(rsp->jiffies_stall, jiffies + ULONG_MAX / 2); } /* @@ -1457,7 +1458,7 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp, * doing some extra useless work. */ if (rnp->gpnum != rnp->completed || - ACCESS_ONCE(rnp_root->gpnum) != ACCESS_ONCE(rnp_root->completed)) { + READ_ONCE(rnp_root->gpnum) != READ_ONCE(rnp_root->completed)) { rnp->need_future_gp[c & 0x1]++; trace_rcu_future_gp(rnp, rdp, c, TPS("Startedleaf")); goto out; @@ -1542,7 +1543,7 @@ static int rcu_future_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp) static void rcu_gp_kthread_wake(struct rcu_state *rsp) { if (current == rsp->gp_kthread || - !ACCESS_ONCE(rsp->gp_flags) || + !READ_ONCE(rsp->gp_flags) || !rsp->gp_kthread) return; wake_up(&rsp->gp_wq); @@ -1677,7 +1678,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp, /* Handle the ends of any preceding grace periods first. */ if (rdp->completed == rnp->completed && - !unlikely(ACCESS_ONCE(rdp->gpwrap))) { + !unlikely(READ_ONCE(rdp->gpwrap))) { /* No grace period end, so just accelerate recent callbacks. */ ret = rcu_accelerate_cbs(rsp, rnp, rdp); @@ -1692,7 +1693,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp, trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuend")); } - if (rdp->gpnum != rnp->gpnum || unlikely(ACCESS_ONCE(rdp->gpwrap))) { + if (rdp->gpnum != rnp->gpnum || unlikely(READ_ONCE(rdp->gpwrap))) { /* * If the current grace period is waiting for this CPU, * set up to detect a quiescent state, otherwise don't @@ -1704,7 +1705,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp, rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr); rdp->qs_pending = !!(rnp->qsmask & rdp->grpmask); zero_cpu_stall_ticks(rdp); - ACCESS_ONCE(rdp->gpwrap) = false; + WRITE_ONCE(rdp->gpwrap, false); } return ret; } @@ -1717,9 +1718,9 @@ static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp) local_irq_save(flags); rnp = rdp->mynode; - if ((rdp->gpnum == ACCESS_ONCE(rnp->gpnum) && - rdp->completed == ACCESS_ONCE(rnp->completed) && - !unlikely(ACCESS_ONCE(rdp->gpwrap))) || /* w/out lock. */ + if ((rdp->gpnum == READ_ONCE(rnp->gpnum) && + rdp->completed == READ_ONCE(rnp->completed) && + !unlikely(READ_ONCE(rdp->gpwrap))) || /* w/out lock. */ !raw_spin_trylock(&rnp->lock)) { /* irqs already off, so later. */ local_irq_restore(flags); return; @@ -1740,15 +1741,15 @@ static int rcu_gp_init(struct rcu_state *rsp) struct rcu_data *rdp; struct rcu_node *rnp = rcu_get_root(rsp); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); raw_spin_lock_irq(&rnp->lock); smp_mb__after_unlock_lock(); - if (!ACCESS_ONCE(rsp->gp_flags)) { + if (!READ_ONCE(rsp->gp_flags)) { /* Spurious wakeup, tell caller to go back to sleep. */ raw_spin_unlock_irq(&rnp->lock); return 0; } - ACCESS_ONCE(rsp->gp_flags) = 0; /* Clear all flags: New grace period. */ + WRITE_ONCE(rsp->gp_flags, 0); /* Clear all flags: New grace period. */ if (WARN_ON_ONCE(rcu_gp_in_progress(rsp))) { /* @@ -1834,9 +1835,9 @@ static int rcu_gp_init(struct rcu_state *rsp) rdp = this_cpu_ptr(rsp->rda); rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; - ACCESS_ONCE(rnp->gpnum) = rsp->gpnum; + WRITE_ONCE(rnp->gpnum, rsp->gpnum); if (WARN_ON_ONCE(rnp->completed != rsp->completed)) - ACCESS_ONCE(rnp->completed) = rsp->completed; + WRITE_ONCE(rnp->completed, rsp->completed); if (rnp == rdp->mynode) (void)__note_gp_changes(rsp, rnp, rdp); rcu_preempt_boost_start_gp(rnp); @@ -1845,7 +1846,7 @@ static int rcu_gp_init(struct rcu_state *rsp) rnp->grphi, rnp->qsmask); raw_spin_unlock_irq(&rnp->lock); cond_resched_rcu_qs(); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); if (gp_init_delay > 0 && !(rsp->gpnum % (rcu_num_nodes * PER_RCU_NODE_PERIOD))) schedule_timeout_uninterruptible(gp_init_delay); @@ -1864,7 +1865,7 @@ static int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in) unsigned long maxj; struct rcu_node *rnp = rcu_get_root(rsp); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); rsp->n_force_qs++; if (fqs_state == RCU_SAVE_DYNTICK) { /* Collect dyntick-idle snapshots. */ @@ -1882,11 +1883,11 @@ static int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in) force_qs_rnp(rsp, rcu_implicit_dynticks_qs, &isidle, &maxj); } /* Clear flag to prevent immediate re-entry. */ - if (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) { + if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) { raw_spin_lock_irq(&rnp->lock); smp_mb__after_unlock_lock(); - ACCESS_ONCE(rsp->gp_flags) = - ACCESS_ONCE(rsp->gp_flags) & ~RCU_GP_FLAG_FQS; + WRITE_ONCE(rsp->gp_flags, + READ_ONCE(rsp->gp_flags) & ~RCU_GP_FLAG_FQS); raw_spin_unlock_irq(&rnp->lock); } return fqs_state; @@ -1903,7 +1904,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) struct rcu_data *rdp; struct rcu_node *rnp = rcu_get_root(rsp); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); raw_spin_lock_irq(&rnp->lock); smp_mb__after_unlock_lock(); gp_duration = jiffies - rsp->gp_start; @@ -1934,7 +1935,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) smp_mb__after_unlock_lock(); WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)); WARN_ON_ONCE(rnp->qsmask); - ACCESS_ONCE(rnp->completed) = rsp->gpnum; + WRITE_ONCE(rnp->completed, rsp->gpnum); rdp = this_cpu_ptr(rsp->rda); if (rnp == rdp->mynode) needgp = __note_gp_changes(rsp, rnp, rdp) || needgp; @@ -1942,7 +1943,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) nocb += rcu_future_gp_cleanup(rsp, rnp); raw_spin_unlock_irq(&rnp->lock); cond_resched_rcu_qs(); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); } rnp = rcu_get_root(rsp); raw_spin_lock_irq(&rnp->lock); @@ -1950,16 +1951,16 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) rcu_nocb_gp_set(rnp, nocb); /* Declare grace period done. */ - ACCESS_ONCE(rsp->completed) = rsp->gpnum; + WRITE_ONCE(rsp->completed, rsp->gpnum); trace_rcu_grace_period(rsp->name, rsp->completed, TPS("end")); rsp->fqs_state = RCU_GP_IDLE; rdp = this_cpu_ptr(rsp->rda); /* Advance CBs to reduce false positives below. */ needgp = rcu_advance_cbs(rsp, rnp, rdp) || needgp; if (needgp || cpu_needs_another_gp(rsp, rdp)) { - ACCESS_ONCE(rsp->gp_flags) = RCU_GP_FLAG_INIT; + WRITE_ONCE(rsp->gp_flags, RCU_GP_FLAG_INIT); trace_rcu_grace_period(rsp->name, - ACCESS_ONCE(rsp->gpnum), + READ_ONCE(rsp->gpnum), TPS("newreq")); } raw_spin_unlock_irq(&rnp->lock); @@ -1983,20 +1984,20 @@ static int __noreturn rcu_gp_kthread(void *arg) /* Handle grace-period start. */ for (;;) { trace_rcu_grace_period(rsp->name, - ACCESS_ONCE(rsp->gpnum), + READ_ONCE(rsp->gpnum), TPS("reqwait")); rsp->gp_state = RCU_GP_WAIT_GPS; wait_event_interruptible(rsp->gp_wq, - ACCESS_ONCE(rsp->gp_flags) & + READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_INIT); /* Locking provides needed memory barrier. */ if (rcu_gp_init(rsp)) break; cond_resched_rcu_qs(); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); WARN_ON(signal_pending(current)); trace_rcu_grace_period(rsp->name, - ACCESS_ONCE(rsp->gpnum), + READ_ONCE(rsp->gpnum), TPS("reqwaitsig")); } @@ -2012,39 +2013,39 @@ static int __noreturn rcu_gp_kthread(void *arg) if (!ret) rsp->jiffies_force_qs = jiffies + j; trace_rcu_grace_period(rsp->name, - ACCESS_ONCE(rsp->gpnum), + READ_ONCE(rsp->gpnum), TPS("fqswait")); rsp->gp_state = RCU_GP_WAIT_FQS; ret = wait_event_interruptible_timeout(rsp->gp_wq, - ((gf = ACCESS_ONCE(rsp->gp_flags)) & + ((gf = READ_ONCE(rsp->gp_flags)) & RCU_GP_FLAG_FQS) || - (!ACCESS_ONCE(rnp->qsmask) && + (!READ_ONCE(rnp->qsmask) && !rcu_preempt_blocked_readers_cgp(rnp)), j); /* Locking provides needed memory barriers. */ /* If grace period done, leave loop. */ - if (!ACCESS_ONCE(rnp->qsmask) && + if (!READ_ONCE(rnp->qsmask) && !rcu_preempt_blocked_readers_cgp(rnp)) break; /* If time for quiescent-state forcing, do it. */ if (ULONG_CMP_GE(jiffies, rsp->jiffies_force_qs) || (gf & RCU_GP_FLAG_FQS)) { trace_rcu_grace_period(rsp->name, - ACCESS_ONCE(rsp->gpnum), + READ_ONCE(rsp->gpnum), TPS("fqsstart")); fqs_state = rcu_gp_fqs(rsp, fqs_state); trace_rcu_grace_period(rsp->name, - ACCESS_ONCE(rsp->gpnum), + READ_ONCE(rsp->gpnum), TPS("fqsend")); cond_resched_rcu_qs(); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); } else { /* Deal with stray signal. */ cond_resched_rcu_qs(); - ACCESS_ONCE(rsp->gp_activity) = jiffies; + WRITE_ONCE(rsp->gp_activity, jiffies); WARN_ON(signal_pending(current)); trace_rcu_grace_period(rsp->name, - ACCESS_ONCE(rsp->gpnum), + READ_ONCE(rsp->gpnum), TPS("fqswaitsig")); } j = jiffies_till_next_fqs; @@ -2086,8 +2087,8 @@ rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp, */ return false; } - ACCESS_ONCE(rsp->gp_flags) = RCU_GP_FLAG_INIT; - trace_rcu_grace_period(rsp->name, ACCESS_ONCE(rsp->gpnum), + WRITE_ONCE(rsp->gp_flags, RCU_GP_FLAG_INIT); + trace_rcu_grace_period(rsp->name, READ_ONCE(rsp->gpnum), TPS("newreq")); /* @@ -2359,7 +2360,7 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, rsp->qlen += rdp->qlen; rdp->n_cbs_orphaned += rdp->qlen; rdp->qlen_lazy = 0; - ACCESS_ONCE(rdp->qlen) = 0; + WRITE_ONCE(rdp->qlen, 0); } /* @@ -2580,7 +2581,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) /* If no callbacks are ready, just return. */ if (!cpu_has_callbacks_ready_to_invoke(rdp)) { trace_rcu_batch_start(rsp->name, rdp->qlen_lazy, rdp->qlen, 0); - trace_rcu_batch_end(rsp->name, 0, !!ACCESS_ONCE(rdp->nxtlist), + trace_rcu_batch_end(rsp->name, 0, !!READ_ONCE(rdp->nxtlist), need_resched(), is_idle_task(current), rcu_is_callbacks_kthread()); return; @@ -2636,7 +2637,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) } smp_mb(); /* List handling before counting for rcu_barrier(). */ rdp->qlen_lazy -= count_lazy; - ACCESS_ONCE(rdp->qlen) = rdp->qlen - count; + WRITE_ONCE(rdp->qlen, rdp->qlen - count); rdp->n_cbs_invoked += count; /* Reinstate batch limit if we have worked down the excess. */ @@ -2793,7 +2794,7 @@ static void force_quiescent_state(struct rcu_state *rsp) /* Funnel through hierarchy to reduce memory contention. */ rnp = __this_cpu_read(rsp->rda->mynode); for (; rnp != NULL; rnp = rnp->parent) { - ret = (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) || + ret = (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) || !raw_spin_trylock(&rnp->fqslock); if (rnp_old != NULL) raw_spin_unlock(&rnp_old->fqslock); @@ -2809,13 +2810,12 @@ static void force_quiescent_state(struct rcu_state *rsp) raw_spin_lock_irqsave(&rnp_old->lock, flags); smp_mb__after_unlock_lock(); raw_spin_unlock(&rnp_old->fqslock); - if (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) { + if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) { rsp->n_force_qs_lh++; raw_spin_unlock_irqrestore(&rnp_old->lock, flags); return; /* Someone beat us to it. */ } - ACCESS_ONCE(rsp->gp_flags) = - ACCESS_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS; + WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS); raw_spin_unlock_irqrestore(&rnp_old->lock, flags); rcu_gp_kthread_wake(rsp); } @@ -2881,7 +2881,7 @@ static void rcu_process_callbacks(struct softirq_action *unused) */ static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) { - if (unlikely(!ACCESS_ONCE(rcu_scheduler_fully_active))) + if (unlikely(!READ_ONCE(rcu_scheduler_fully_active))) return; if (likely(!rsp->boost)) { rcu_do_batch(rsp, rdp); @@ -2972,7 +2972,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), WARN_ON_ONCE((unsigned long)head & 0x1); /* Misaligned rcu_head! */ if (debug_rcu_head_queue(head)) { /* Probable double call_rcu(), so leak the callback. */ - ACCESS_ONCE(head->func) = rcu_leak_callback; + WRITE_ONCE(head->func, rcu_leak_callback); WARN_ONCE(1, "__call_rcu(): Leaked duplicate callback\n"); return; } @@ -3011,7 +3011,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), if (!likely(rdp->nxtlist)) init_default_callback_list(rdp); } - ACCESS_ONCE(rdp->qlen) = rdp->qlen + 1; + WRITE_ONCE(rdp->qlen, rdp->qlen + 1); if (lazy) rdp->qlen_lazy++; else @@ -3450,14 +3450,14 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) } /* Has another RCU grace period completed? */ - if (ACCESS_ONCE(rnp->completed) != rdp->completed) { /* outside lock */ + if (READ_ONCE(rnp->completed) != rdp->completed) { /* outside lock */ rdp->n_rp_gp_completed++; return 1; } /* Has a new RCU grace period started? */ - if (ACCESS_ONCE(rnp->gpnum) != rdp->gpnum || - unlikely(ACCESS_ONCE(rdp->gpwrap))) { /* outside lock */ + if (READ_ONCE(rnp->gpnum) != rdp->gpnum || + unlikely(READ_ONCE(rdp->gpwrap))) { /* outside lock */ rdp->n_rp_gp_started++; return 1; } @@ -3564,7 +3564,7 @@ static void _rcu_barrier(struct rcu_state *rsp) { int cpu; struct rcu_data *rdp; - unsigned long snap = ACCESS_ONCE(rsp->n_barrier_done); + unsigned long snap = READ_ONCE(rsp->n_barrier_done); unsigned long snap_done; _rcu_barrier_trace(rsp, "Begin", -1, snap); @@ -3606,10 +3606,10 @@ static void _rcu_barrier(struct rcu_state *rsp) /* * Increment ->n_barrier_done to avoid duplicate work. Use - * ACCESS_ONCE() to prevent the compiler from speculating + * WRITE_ONCE() to prevent the compiler from speculating * the increment to precede the early-exit check. */ - ACCESS_ONCE(rsp->n_barrier_done) = rsp->n_barrier_done + 1; + WRITE_ONCE(rsp->n_barrier_done, rsp->n_barrier_done + 1); WARN_ON_ONCE((rsp->n_barrier_done & 0x1) != 1); _rcu_barrier_trace(rsp, "Inc1", -1, rsp->n_barrier_done); smp_mb(); /* Order ->n_barrier_done increment with below mechanism. */ @@ -3645,7 +3645,7 @@ static void _rcu_barrier(struct rcu_state *rsp) __call_rcu(&rdp->barrier_head, rcu_barrier_callback, rsp, cpu, 0); } - } else if (ACCESS_ONCE(rdp->qlen)) { + } else if (READ_ONCE(rdp->qlen)) { _rcu_barrier_trace(rsp, "OnlineQ", cpu, rsp->n_barrier_done); smp_call_function_single(cpu, rcu_barrier_func, rsp, 1); @@ -3665,7 +3665,7 @@ static void _rcu_barrier(struct rcu_state *rsp) /* Increment ->n_barrier_done to prevent duplicate work. */ smp_mb(); /* Keep increment after above mechanism. */ - ACCESS_ONCE(rsp->n_barrier_done) = rsp->n_barrier_done + 1; + WRITE_ONCE(rsp->n_barrier_done, rsp->n_barrier_done + 1); WARN_ON_ONCE((rsp->n_barrier_done & 0x1) != 0); _rcu_barrier_trace(rsp, "Inc2", -1, rsp->n_barrier_done); smp_mb(); /* Keep increment before caller's subsequent code. */ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 8c0ec0f5a027..58b1ebdc4387 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -570,7 +570,7 @@ static int rcu_preempted_readers_exp(struct rcu_node *rnp) static int sync_rcu_preempt_exp_done(struct rcu_node *rnp) { return !rcu_preempted_readers_exp(rnp) && - ACCESS_ONCE(rnp->expmask) == 0; + READ_ONCE(rnp->expmask) == 0; } /* @@ -716,7 +716,7 @@ void synchronize_rcu_expedited(void) int trycount = 0; smp_mb(); /* Caller's modifications seen first by other CPUs. */ - snap = ACCESS_ONCE(sync_rcu_preempt_exp_count) + 1; + snap = READ_ONCE(sync_rcu_preempt_exp_count) + 1; smp_mb(); /* Above access cannot bleed into critical section. */ /* @@ -740,7 +740,7 @@ void synchronize_rcu_expedited(void) */ while (!mutex_trylock(&sync_rcu_preempt_exp_mutex)) { if (ULONG_CMP_LT(snap, - ACCESS_ONCE(sync_rcu_preempt_exp_count))) { + READ_ONCE(sync_rcu_preempt_exp_count))) { put_online_cpus(); goto mb_ret; /* Others did our work for us. */ } @@ -752,7 +752,7 @@ void synchronize_rcu_expedited(void) return; } } - if (ULONG_CMP_LT(snap, ACCESS_ONCE(sync_rcu_preempt_exp_count))) { + if (ULONG_CMP_LT(snap, READ_ONCE(sync_rcu_preempt_exp_count))) { put_online_cpus(); goto unlock_mb_ret; /* Others did our work for us. */ } @@ -780,8 +780,7 @@ void synchronize_rcu_expedited(void) /* Clean up and exit. */ smp_mb(); /* ensure expedited GP seen before counter increment. */ - ACCESS_ONCE(sync_rcu_preempt_exp_count) = - sync_rcu_preempt_exp_count + 1; + WRITE_ONCE(sync_rcu_preempt_exp_count, sync_rcu_preempt_exp_count + 1); unlock_mb_ret: mutex_unlock(&sync_rcu_preempt_exp_mutex); mb_ret: @@ -994,8 +993,8 @@ static int rcu_boost(struct rcu_node *rnp) struct task_struct *t; struct list_head *tb; - if (ACCESS_ONCE(rnp->exp_tasks) == NULL && - ACCESS_ONCE(rnp->boost_tasks) == NULL) + if (READ_ONCE(rnp->exp_tasks) == NULL && + READ_ONCE(rnp->boost_tasks) == NULL) return 0; /* Nothing left to boost. */ raw_spin_lock_irqsave(&rnp->lock, flags); @@ -1048,8 +1047,8 @@ static int rcu_boost(struct rcu_node *rnp) rt_mutex_lock(&rnp->boost_mtx); rt_mutex_unlock(&rnp->boost_mtx); /* Then keep lockdep happy. */ - return ACCESS_ONCE(rnp->exp_tasks) != NULL || - ACCESS_ONCE(rnp->boost_tasks) != NULL; + return READ_ONCE(rnp->exp_tasks) != NULL || + READ_ONCE(rnp->boost_tasks) != NULL; } /* @@ -1462,7 +1461,7 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void) * callbacks not yet ready to invoke. */ if ((rdp->completed != rnp->completed || - unlikely(ACCESS_ONCE(rdp->gpwrap))) && + unlikely(READ_ONCE(rdp->gpwrap))) && rdp->nxttail[RCU_DONE_TAIL] != rdp->nxttail[RCU_NEXT_TAIL]) note_gp_changes(rsp, rdp); @@ -1534,7 +1533,7 @@ static void rcu_prepare_for_idle(void) int tne; /* Handle nohz enablement switches conservatively. */ - tne = ACCESS_ONCE(tick_nohz_active); + tne = READ_ONCE(tick_nohz_active); if (tne != rdtp->tick_nohz_enabled_snap) { if (rcu_cpu_has_callbacks(NULL)) invoke_rcu_core(); /* force nohz to see update. */ @@ -1760,7 +1759,7 @@ static void print_cpu_stall_info(struct rcu_state *rsp, int cpu) atomic_read(&rdtp->dynticks) & 0xfff, rdtp->dynticks_nesting, rdtp->dynticks_nmi_nesting, rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu), - ACCESS_ONCE(rsp->n_force_qs) - rsp->n_force_qs_gpstart, + READ_ONCE(rsp->n_force_qs) - rsp->n_force_qs_gpstart, fast_no_hz); } @@ -1898,11 +1897,11 @@ static void wake_nocb_leader(struct rcu_data *rdp, bool force) { struct rcu_data *rdp_leader = rdp->nocb_leader; - if (!ACCESS_ONCE(rdp_leader->nocb_kthread)) + if (!READ_ONCE(rdp_leader->nocb_kthread)) return; - if (ACCESS_ONCE(rdp_leader->nocb_leader_sleep) || force) { + if (READ_ONCE(rdp_leader->nocb_leader_sleep) || force) { /* Prior smp_mb__after_atomic() orders against prior enqueue. */ - ACCESS_ONCE(rdp_leader->nocb_leader_sleep) = false; + WRITE_ONCE(rdp_leader->nocb_leader_sleep, false); wake_up(&rdp_leader->nocb_wq); } } @@ -1934,14 +1933,14 @@ static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu) ret = atomic_long_read(&rdp->nocb_q_count); #ifdef CONFIG_PROVE_RCU - rhp = ACCESS_ONCE(rdp->nocb_head); + rhp = READ_ONCE(rdp->nocb_head); if (!rhp) - rhp = ACCESS_ONCE(rdp->nocb_gp_head); + rhp = READ_ONCE(rdp->nocb_gp_head); if (!rhp) - rhp = ACCESS_ONCE(rdp->nocb_follower_head); + rhp = READ_ONCE(rdp->nocb_follower_head); /* Having no rcuo kthread but CBs after scheduler starts is bad! */ - if (!ACCESS_ONCE(rdp->nocb_kthread) && rhp && + if (!READ_ONCE(rdp->nocb_kthread) && rhp && rcu_scheduler_fully_active) { /* RCU callback enqueued before CPU first came online??? */ pr_err("RCU: Never-onlined no-CBs CPU %d has CB %p\n", @@ -1975,12 +1974,12 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp, atomic_long_add(rhcount, &rdp->nocb_q_count); /* rcu_barrier() relies on ->nocb_q_count add before xchg. */ old_rhpp = xchg(&rdp->nocb_tail, rhtp); - ACCESS_ONCE(*old_rhpp) = rhp; + WRITE_ONCE(*old_rhpp, rhp); atomic_long_add(rhcount_lazy, &rdp->nocb_q_count_lazy); smp_mb__after_atomic(); /* Store *old_rhpp before _wake test. */ /* If we are not being polled and there is a kthread, awaken it ... */ - t = ACCESS_ONCE(rdp->nocb_kthread); + t = READ_ONCE(rdp->nocb_kthread); if (rcu_nocb_poll || !t) { trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeNotPoll")); @@ -2118,7 +2117,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) for (;;) { wait_event_interruptible( rnp->nocb_gp_wq[c & 0x1], - (d = ULONG_CMP_GE(ACCESS_ONCE(rnp->completed), c))); + (d = ULONG_CMP_GE(READ_ONCE(rnp->completed), c))); if (likely(d)) break; WARN_ON(signal_pending(current)); @@ -2145,7 +2144,7 @@ wait_again: if (!rcu_nocb_poll) { trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep"); wait_event_interruptible(my_rdp->nocb_wq, - !ACCESS_ONCE(my_rdp->nocb_leader_sleep)); + !READ_ONCE(my_rdp->nocb_leader_sleep)); /* Memory barrier handled by smp_mb() calls below and repoll. */ } else if (firsttime) { firsttime = false; /* Don't drown trace log with "Poll"! */ @@ -2159,12 +2158,12 @@ wait_again: */ gotcbs = false; for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) { - rdp->nocb_gp_head = ACCESS_ONCE(rdp->nocb_head); + rdp->nocb_gp_head = READ_ONCE(rdp->nocb_head); if (!rdp->nocb_gp_head) continue; /* No CBs here, try next follower. */ /* Move callbacks to wait-for-GP list, which is empty. */ - ACCESS_ONCE(rdp->nocb_head) = NULL; + WRITE_ONCE(rdp->nocb_head, NULL); rdp->nocb_gp_tail = xchg(&rdp->nocb_tail, &rdp->nocb_head); gotcbs = true; } @@ -2184,7 +2183,7 @@ wait_again: my_rdp->nocb_leader_sleep = true; smp_mb(); /* Ensure _sleep true before scan. */ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) - if (ACCESS_ONCE(rdp->nocb_head)) { + if (READ_ONCE(rdp->nocb_head)) { /* Found CB, so short-circuit next wait. */ my_rdp->nocb_leader_sleep = false; break; @@ -2205,7 +2204,7 @@ wait_again: /* Each pass through the following loop wakes a follower, if needed. */ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) { - if (ACCESS_ONCE(rdp->nocb_head)) + if (READ_ONCE(rdp->nocb_head)) my_rdp->nocb_leader_sleep = false;/* No need to sleep.*/ if (!rdp->nocb_gp_head) continue; /* No CBs, so no need to wake follower. */ @@ -2241,7 +2240,7 @@ static void nocb_follower_wait(struct rcu_data *rdp) trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "FollowerSleep"); wait_event_interruptible(rdp->nocb_wq, - ACCESS_ONCE(rdp->nocb_follower_head)); + READ_ONCE(rdp->nocb_follower_head)); } else if (firsttime) { /* Don't drown trace log with "Poll"! */ firsttime = false; @@ -2282,10 +2281,10 @@ static int rcu_nocb_kthread(void *arg) nocb_follower_wait(rdp); /* Pull the ready-to-invoke callbacks onto local list. */ - list = ACCESS_ONCE(rdp->nocb_follower_head); + list = READ_ONCE(rdp->nocb_follower_head); BUG_ON(!list); trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeNonEmpty"); - ACCESS_ONCE(rdp->nocb_follower_head) = NULL; + WRITE_ONCE(rdp->nocb_follower_head, NULL); tail = xchg(&rdp->nocb_follower_tail, &rdp->nocb_follower_head); /* Each pass through the following loop invokes a callback. */ @@ -2324,7 +2323,7 @@ static int rcu_nocb_kthread(void *arg) /* Is a deferred wakeup of rcu_nocb_kthread() required? */ static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp) { - return ACCESS_ONCE(rdp->nocb_defer_wakeup); + return READ_ONCE(rdp->nocb_defer_wakeup); } /* Do a deferred wakeup of rcu_nocb_kthread(). */ @@ -2334,8 +2333,8 @@ static void do_nocb_deferred_wakeup(struct rcu_data *rdp) if (!rcu_nocb_need_deferred_wakeup(rdp)) return; - ndw = ACCESS_ONCE(rdp->nocb_defer_wakeup); - ACCESS_ONCE(rdp->nocb_defer_wakeup) = RCU_NOGP_WAKE_NOT; + ndw = READ_ONCE(rdp->nocb_defer_wakeup); + WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOGP_WAKE_NOT); wake_nocb_leader(rdp, ndw == RCU_NOGP_WAKE_FORCE); trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWake")); } @@ -2448,7 +2447,7 @@ static void rcu_spawn_one_nocb_kthread(struct rcu_state *rsp, int cpu) t = kthread_run(rcu_nocb_kthread, rdp_spawn, "rcuo%c/%d", rsp->abbr, cpu); BUG_ON(IS_ERR(t)); - ACCESS_ONCE(rdp_spawn->nocb_kthread) = t; + WRITE_ONCE(rdp_spawn->nocb_kthread, t); } /* @@ -2663,7 +2662,7 @@ static void rcu_sysidle_enter(int irq) /* Record start of fully idle period. */ j = jiffies; - ACCESS_ONCE(rdtp->dynticks_idle_jiffies) = j; + WRITE_ONCE(rdtp->dynticks_idle_jiffies, j); smp_mb__before_atomic(); atomic_inc(&rdtp->dynticks_idle); smp_mb__after_atomic(); @@ -2681,7 +2680,7 @@ static void rcu_sysidle_enter(int irq) */ void rcu_sysidle_force_exit(void) { - int oldstate = ACCESS_ONCE(full_sysidle_state); + int oldstate = READ_ONCE(full_sysidle_state); int newoldstate; /* @@ -2794,7 +2793,7 @@ static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle, smp_mb(); /* Read counters before timestamps. */ /* Pick up timestamps. */ - j = ACCESS_ONCE(rdtp->dynticks_idle_jiffies); + j = READ_ONCE(rdtp->dynticks_idle_jiffies); /* If this CPU entered idle more recently, update maxj timestamp. */ if (ULONG_CMP_LT(*maxj, j)) *maxj = j; @@ -2831,11 +2830,11 @@ static unsigned long rcu_sysidle_delay(void) static void rcu_sysidle(unsigned long j) { /* Check the current state. */ - switch (ACCESS_ONCE(full_sysidle_state)) { + switch (READ_ONCE(full_sysidle_state)) { case RCU_SYSIDLE_NOT: /* First time all are idle, so note a short idle period. */ - ACCESS_ONCE(full_sysidle_state) = RCU_SYSIDLE_SHORT; + WRITE_ONCE(full_sysidle_state, RCU_SYSIDLE_SHORT); break; case RCU_SYSIDLE_SHORT: @@ -2873,7 +2872,7 @@ static void rcu_sysidle_cancel(void) { smp_mb(); if (full_sysidle_state > RCU_SYSIDLE_SHORT) - ACCESS_ONCE(full_sysidle_state) = RCU_SYSIDLE_NOT; + WRITE_ONCE(full_sysidle_state, RCU_SYSIDLE_NOT); } /* @@ -2925,7 +2924,7 @@ static void rcu_sysidle_cb(struct rcu_head *rhp) smp_mb(); /* grace period precedes setting inuse. */ rshp = container_of(rhp, struct rcu_sysidle_head, rh); - ACCESS_ONCE(rshp->inuse) = 0; + WRITE_ONCE(rshp->inuse, 0); } /* @@ -2936,7 +2935,7 @@ static void rcu_sysidle_cb(struct rcu_head *rhp) bool rcu_sys_is_idle(void) { static struct rcu_sysidle_head rsh; - int rss = ACCESS_ONCE(full_sysidle_state); + int rss = READ_ONCE(full_sysidle_state); if (WARN_ON_ONCE(smp_processor_id() != tick_do_timer_cpu)) return false; @@ -2964,7 +2963,7 @@ bool rcu_sys_is_idle(void) } rcu_sysidle_report(rcu_state_p, isidle, maxj, false); oldrss = rss; - rss = ACCESS_ONCE(full_sysidle_state); + rss = READ_ONCE(full_sysidle_state); } } @@ -3048,7 +3047,7 @@ static bool rcu_nohz_full_cpu(struct rcu_state *rsp) #ifdef CONFIG_NO_HZ_FULL if (tick_nohz_full_cpu(smp_processor_id()) && (!rcu_gp_in_progress(rsp) || - ULONG_CMP_LT(jiffies, ACCESS_ONCE(rsp->gp_start) + HZ))) + ULONG_CMP_LT(jiffies, READ_ONCE(rsp->gp_start) + HZ))) return 1; #endif /* #ifdef CONFIG_NO_HZ_FULL */ return 0; @@ -3077,7 +3076,7 @@ static void rcu_bind_gp_kthread(void) static void rcu_dynticks_task_enter(void) { #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) - ACCESS_ONCE(current->rcu_tasks_idle_cpu) = smp_processor_id(); + WRITE_ONCE(current->rcu_tasks_idle_cpu, smp_processor_id()); #endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */ } @@ -3085,6 +3084,6 @@ static void rcu_dynticks_task_enter(void) static void rcu_dynticks_task_exit(void) { #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) - ACCESS_ONCE(current->rcu_tasks_idle_cpu) = -1; + WRITE_ONCE(current->rcu_tasks_idle_cpu, -1); #endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */ } diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c index f92361efd0f5..3ea7ffc7d5c4 100644 --- a/kernel/rcu/tree_trace.c +++ b/kernel/rcu/tree_trace.c @@ -277,7 +277,7 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n", rsp->n_force_qs, rsp->n_force_qs_ngp, rsp->n_force_qs - rsp->n_force_qs_ngp, - ACCESS_ONCE(rsp->n_force_qs_lh), rsp->qlen_lazy, rsp->qlen); + READ_ONCE(rsp->n_force_qs_lh), rsp->qlen_lazy, rsp->qlen); for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) { if (rnp->level != level) { seq_puts(m, "\n"); @@ -323,8 +323,8 @@ static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp) struct rcu_node *rnp = &rsp->node[0]; raw_spin_lock_irqsave(&rnp->lock, flags); - completed = ACCESS_ONCE(rsp->completed); - gpnum = ACCESS_ONCE(rsp->gpnum); + completed = READ_ONCE(rsp->completed); + gpnum = READ_ONCE(rsp->gpnum); if (completed == gpnum) gpage = 0; else diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 1f133350da01..afaecb7a799a 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -150,14 +150,14 @@ void __rcu_read_unlock(void) barrier(); /* critical section before exit code. */ t->rcu_read_lock_nesting = INT_MIN; barrier(); /* assign before ->rcu_read_unlock_special load */ - if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special.s))) + if (unlikely(READ_ONCE(t->rcu_read_unlock_special.s))) rcu_read_unlock_special(t); barrier(); /* ->rcu_read_unlock_special load before assign */ t->rcu_read_lock_nesting = 0; } #ifdef CONFIG_PROVE_LOCKING { - int rrln = ACCESS_ONCE(t->rcu_read_lock_nesting); + int rrln = READ_ONCE(t->rcu_read_lock_nesting); WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2); } @@ -389,17 +389,17 @@ module_param(rcu_cpu_stall_timeout, int, 0644); int rcu_jiffies_till_stall_check(void) { - int till_stall_check = ACCESS_ONCE(rcu_cpu_stall_timeout); + int till_stall_check = READ_ONCE(rcu_cpu_stall_timeout); /* * Limit check must be consistent with the Kconfig limits * for CONFIG_RCU_CPU_STALL_TIMEOUT. */ if (till_stall_check < 3) { - ACCESS_ONCE(rcu_cpu_stall_timeout) = 3; + WRITE_ONCE(rcu_cpu_stall_timeout, 3); till_stall_check = 3; } else if (till_stall_check > 300) { - ACCESS_ONCE(rcu_cpu_stall_timeout) = 300; + WRITE_ONCE(rcu_cpu_stall_timeout, 300); till_stall_check = 300; } return till_stall_check * HZ + RCU_STALL_DELAY_DELTA; @@ -550,12 +550,12 @@ static void check_holdout_task(struct task_struct *t, { int cpu; - if (!ACCESS_ONCE(t->rcu_tasks_holdout) || - t->rcu_tasks_nvcsw != ACCESS_ONCE(t->nvcsw) || - !ACCESS_ONCE(t->on_rq) || + if (!READ_ONCE(t->rcu_tasks_holdout) || + t->rcu_tasks_nvcsw != READ_ONCE(t->nvcsw) || + !READ_ONCE(t->on_rq) || (IS_ENABLED(CONFIG_NO_HZ_FULL) && !is_idle_task(t) && t->rcu_tasks_idle_cpu >= 0)) { - ACCESS_ONCE(t->rcu_tasks_holdout) = false; + WRITE_ONCE(t->rcu_tasks_holdout, false); list_del_init(&t->rcu_tasks_holdout_list); put_task_struct(t); return; @@ -639,11 +639,11 @@ static int __noreturn rcu_tasks_kthread(void *arg) */ rcu_read_lock(); for_each_process_thread(g, t) { - if (t != current && ACCESS_ONCE(t->on_rq) && + if (t != current && READ_ONCE(t->on_rq) && !is_idle_task(t)) { get_task_struct(t); - t->rcu_tasks_nvcsw = ACCESS_ONCE(t->nvcsw); - ACCESS_ONCE(t->rcu_tasks_holdout) = true; + t->rcu_tasks_nvcsw = READ_ONCE(t->nvcsw); + WRITE_ONCE(t->rcu_tasks_holdout, true); list_add(&t->rcu_tasks_holdout_list, &rcu_tasks_holdouts); } @@ -672,7 +672,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) struct task_struct *t1; schedule_timeout_interruptible(HZ); - rtst = ACCESS_ONCE(rcu_task_stall_timeout); + rtst = READ_ONCE(rcu_task_stall_timeout); needreport = rtst > 0 && time_after(jiffies, lastreport + rtst); if (needreport) @@ -728,7 +728,7 @@ static void rcu_spawn_tasks_kthread(void) static struct task_struct *rcu_tasks_kthread_ptr; struct task_struct *t; - if (ACCESS_ONCE(rcu_tasks_kthread_ptr)) { + if (READ_ONCE(rcu_tasks_kthread_ptr)) { smp_mb(); /* Ensure caller sees full kthread. */ return; } @@ -740,7 +740,7 @@ static void rcu_spawn_tasks_kthread(void) t = kthread_run(rcu_tasks_kthread, NULL, "rcu_tasks_kthread"); BUG_ON(IS_ERR(t)); smp_mb(); /* Ensure others see full kthread. */ - ACCESS_ONCE(rcu_tasks_kthread_ptr) = t; + WRITE_ONCE(rcu_tasks_kthread_ptr, t); mutex_unlock(&rcu_tasks_kthread_mutex); } diff --git a/kernel/torture.c b/kernel/torture.c index dd70993c266c..3e4840633d3e 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -409,7 +409,7 @@ static void (*torture_shutdown_hook)(void); */ void torture_shutdown_absorb(const char *title) { - while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { + while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { pr_notice("torture thread %s parking due to system shutdown\n", title); schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT); @@ -480,9 +480,9 @@ static int torture_shutdown_notify(struct notifier_block *unused1, unsigned long unused2, void *unused3) { mutex_lock(&fullstop_mutex); - if (ACCESS_ONCE(fullstop) == FULLSTOP_DONTSTOP) { + if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) { VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected"); - ACCESS_ONCE(fullstop) = FULLSTOP_SHUTDOWN; + WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN); } else { pr_warn("Concurrent rmmod and shutdown illegal!\n"); } @@ -523,13 +523,13 @@ static int stutter; */ void stutter_wait(const char *title) { - while (ACCESS_ONCE(stutter_pause_test) || - (torture_runnable && !ACCESS_ONCE(*torture_runnable))) { + while (READ_ONCE(stutter_pause_test) || + (torture_runnable && !READ_ONCE(*torture_runnable))) { if (stutter_pause_test) - if (ACCESS_ONCE(stutter_pause_test) == 1) + if (READ_ONCE(stutter_pause_test) == 1) schedule_timeout_interruptible(1); else - while (ACCESS_ONCE(stutter_pause_test)) + while (READ_ONCE(stutter_pause_test)) cond_resched(); else schedule_timeout_interruptible(round_jiffies_relative(HZ)); @@ -549,14 +549,14 @@ static int torture_stutter(void *arg) if (!torture_must_stop()) { if (stutter > 1) { schedule_timeout_interruptible(stutter - 1); - ACCESS_ONCE(stutter_pause_test) = 2; + WRITE_ONCE(stutter_pause_test, 2); } schedule_timeout_interruptible(1); - ACCESS_ONCE(stutter_pause_test) = 1; + WRITE_ONCE(stutter_pause_test, 1); } if (!torture_must_stop()) schedule_timeout_interruptible(stutter); - ACCESS_ONCE(stutter_pause_test) = 0; + WRITE_ONCE(stutter_pause_test, 0); torture_shutdown_absorb("torture_stutter"); } while (!torture_must_stop()); torture_kthread_stopping("torture_stutter"); @@ -642,13 +642,13 @@ EXPORT_SYMBOL_GPL(torture_init_end); bool torture_cleanup_begin(void) { mutex_lock(&fullstop_mutex); - if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { + if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { pr_warn("Concurrent rmmod and shutdown illegal!\n"); mutex_unlock(&fullstop_mutex); schedule_timeout_uninterruptible(10); return true; } - ACCESS_ONCE(fullstop) = FULLSTOP_RMMOD; + WRITE_ONCE(fullstop, FULLSTOP_RMMOD); mutex_unlock(&fullstop_mutex); torture_shutdown_cleanup(); torture_shuffle_cleanup(); @@ -681,7 +681,7 @@ EXPORT_SYMBOL_GPL(torture_must_stop); */ bool torture_must_stop_irq(void) { - return ACCESS_ONCE(fullstop) != FULLSTOP_DONTSTOP; + return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP; } EXPORT_SYMBOL_GPL(torture_must_stop_irq); |