[PATCH tip/core/rcu 19/24] rcu: Clean up flavor-related definitions and comments in tree_exp.h

From: Paul E. McKenney
Date: Wed Aug 29 2018 - 18:55:51 EST


Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree_exp.h | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 060bdb45cd95..78553a8fa3c6 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -601,8 +601,8 @@ static void wait_rcu_exp_gp(struct work_struct *wp)
}

/*
- * Given an rcu_state pointer and a smp_call_function() handler, kick
- * off the specified flavor of expedited grace period.
+ * Given a smp_call_function() handler, kick off the specified
+ * implementation of expedited grace period.
*/
static void _synchronize_rcu_expedited(smp_call_func_t func)
{
@@ -721,7 +721,7 @@ static void sync_rcu_exp_handler(void *unused)
resched_cpu(rdp->cpu);
}

-/* PREEMPT=y, so no RCU-sched to clean up after. */
+/* PREEMPT=y, so no PREEMPT=n expedited grace period to clean up after. */
static void sync_sched_exp_online_cleanup(int cpu)
{
}
@@ -798,13 +798,13 @@ static void sync_sched_exp_online_cleanup(int cpu)
}

/*
- * Because a context switch is a grace period for RCU-sched, any blocking
- * grace-period wait automatically implies a grace period if there
- * is only one CPU online at any point time during execution of either
- * synchronize_sched() or synchronize_rcu_bh(). It is OK to occasionally
- * incorrectly indicate that there are multiple CPUs online when there
- * was in fact only one the whole time, as this just adds some overhead:
- * RCU still operates correctly.
+ * Because a context switch is a grace period for !PREEMPT, any
+ * blocking grace-period wait automatically implies a grace period if
+ * there is only one CPU online at any point time during execution of
+ * either synchronize_rcu() or synchronize_rcu_expedited(). It is OK to
+ * occasionally incorrectly indicate that there are multiple CPUs online
+ * when there was in fact only one the whole time, as this just adds some
+ * overhead: RCU still operates correctly.
*/
static int rcu_blocking_is_gp(void)
{
@@ -823,7 +823,7 @@ void synchronize_rcu_expedited(void)
RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) ||
lock_is_held(&rcu_sched_lock_map),
- "Illegal synchronize_sched_expedited() in RCU read-side critical section");
+ "Illegal synchronize_rcu_expedited() in RCU read-side critical section");

/* If only one CPU, this is automatically a grace period. */
if (rcu_blocking_is_gp())
--
2.17.1