diff options
Diffstat (limited to 'kernel/rcu/update.c')
| -rw-r--r-- | kernel/rcu/update.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index d98a5c38e19c..b62735a67884 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -538,6 +538,28 @@ long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool do EXPORT_SYMBOL_GPL(torture_sched_setaffinity); #endif +#if IS_ENABLED(CONFIG_TRIVIAL_PREEMPT_RCU) +// Trivial and stupid grace-period wait. Defined here so that lockdep +// kernels can find tasklist_lock. +void synchronize_rcu_trivial_preempt(void) +{ + struct task_struct *g; + struct task_struct *t; + + smp_mb(); // Order prior accesses before grace-period start. + rcu_read_lock(); // Protect task list. + for_each_process_thread(g, t) { + if (t == current) + continue; // Don't deadlock on ourselves! + // Order later rcu_read_lock() on other tasks after QS. + while (smp_load_acquire(&t->rcu_trivial_preempt_nesting)) + continue; + } + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_trivial_preempt); +#endif // #if IS_ENABLED(CONFIG_TRIVIAL_PREEMPT_RCU) + int rcu_cpu_stall_notifiers __read_mostly; // !0 = provide stall notifiers (rarely useful) EXPORT_SYMBOL_GPL(rcu_cpu_stall_notifiers); |