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-rw-r--r--kernel/rcu/tree_exp.h52
1 files changed, 41 insertions, 11 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index d3053e99fdb6..e59e1849b89a 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -532,18 +532,28 @@ struct rcu_exp_work {
};
/*
+ * Common code to drive an expedited grace period forward, used by
+ * workqueues and mid-boot-time tasks.
+ */
+static void rcu_exp_sel_wait_wake(struct rcu_state *rsp,
+ smp_call_func_t func, unsigned long s)
+{
+ /* Initialize the rcu_node tree in preparation for the wait. */
+ sync_rcu_exp_select_cpus(rsp, func);
+
+ /* Wait and clean up, including waking everyone. */
+ rcu_exp_wait_wake(rsp, s);
+}
+
+/*
* Work-queue handler to drive an expedited grace period forward.
*/
static void wait_rcu_exp_gp(struct work_struct *wp)
{
struct rcu_exp_work *rewp;
- /* Initialize the rcu_node tree in preparation for the wait. */
rewp = container_of(wp, struct rcu_exp_work, rew_work);
- sync_rcu_exp_select_cpus(rewp->rew_rsp, rewp->rew_func);
-
- /* Wait and clean up, including waking everyone. */
- rcu_exp_wait_wake(rewp->rew_rsp, rewp->rew_s);
+ rcu_exp_sel_wait_wake(rewp->rew_rsp, rewp->rew_func, rewp->rew_s);
}
/*
@@ -569,12 +579,18 @@ static void _synchronize_rcu_expedited(struct rcu_state *rsp,
if (exp_funnel_lock(rsp, s))
return; /* Someone else did our work for us. */
- /* Marshall arguments and schedule the expedited grace period. */
- rew.rew_func = func;
- rew.rew_rsp = rsp;
- rew.rew_s = s;
- INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp);
- schedule_work(&rew.rew_work);
+ /* Ensure that load happens before action based on it. */
+ if (unlikely(rcu_scheduler_active == RCU_SCHEDULER_INIT)) {
+ /* Direct call during scheduler init and early_initcalls(). */
+ rcu_exp_sel_wait_wake(rsp, func, s);
+ } else {
+ /* Marshall arguments & schedule the expedited grace period. */
+ rew.rew_func = func;
+ rew.rew_rsp = rsp;
+ rew.rew_s = s;
+ INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp);
+ schedule_work(&rew.rew_work);
+ }
/* Wait for expedited grace period to complete. */
rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id());
@@ -676,6 +692,8 @@ void synchronize_rcu_expedited(void)
{
struct rcu_state *rsp = rcu_state_p;
+ if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
+ return;
_synchronize_rcu_expedited(rsp, sync_rcu_exp_handler);
}
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
@@ -693,3 +711,15 @@ void synchronize_rcu_expedited(void)
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+
+/*
+ * Switch to run-time mode once Tree RCU has fully initialized.
+ */
+static int __init rcu_exp_runtime_mode(void)
+{
+ rcu_test_sync_prims();
+ rcu_scheduler_active = RCU_SCHEDULER_RUNNING;
+ rcu_test_sync_prims();
+ return 0;
+}
+core_initcall(rcu_exp_runtime_mode);
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