[PATCH tip/core/rcu 10/24] rcu: Clean up flavor-related definitions and comments in rcupdate.h

From: Paul E. McKenney
Date: Wed Aug 29 2018 - 18:54:31 EST


Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/rcupdate.h | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 12103e1bbe67..d6d543b60a9f 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -119,11 +119,10 @@ static inline void rcu_init_nohz(void) { }
* RCU_NONIDLE - Indicate idle-loop code that needs RCU readers
* @a: Code that RCU needs to pay attention to.
*
- * RCU, RCU-bh, and RCU-sched read-side critical sections are forbidden
- * in the inner idle loop, that is, between the rcu_idle_enter() and
- * the rcu_idle_exit() -- RCU will happily ignore any such read-side
- * critical sections. However, things like powertop need tracepoints
- * in the inner idle loop.
+ * RCU read-side critical sections are forbidden in the inner idle loop,
+ * that is, between the rcu_idle_enter() and the rcu_idle_exit() -- RCU
+ * will happily ignore any such read-side critical sections. However,
+ * things like powertop need tracepoints in the inner idle loop.
*
* This macro provides the way out: RCU_NONIDLE(do_something_with_RCU())
* will tell RCU that it needs to pay attention, invoke its argument
@@ -163,7 +162,7 @@ void exit_tasks_rcu_finish(void);
#else /* #ifdef CONFIG_TASKS_RCU */
#define rcu_tasks_qs(t) do { } while (0)
#define rcu_note_voluntary_context_switch(t) rcu_all_qs()
-#define call_rcu_tasks call_rcu_sched
+#define call_rcu_tasks call_rcu
#define synchronize_rcu_tasks synchronize_rcu
static inline void exit_tasks_rcu_start(void) { }
static inline void exit_tasks_rcu_finish(void) { }
@@ -309,8 +308,8 @@ static inline void rcu_preempt_sleep_check(void) { }
* Helper functions for rcu_dereference_check(), rcu_dereference_protected()
* and rcu_assign_pointer(). Some of these could be folded into their
* callers, but they are left separate in order to ease introduction of
- * multiple flavors of pointers to match the multiple flavors of RCU
- * (e.g., __rcu_sched, and __srcu), should this make sense in the future.
+ * multiple pointers markings to match different RCU implementations
+ * (e.g., __srcu), should this make sense in the future.
*/

#ifdef __CHECKER__
@@ -670,9 +669,8 @@ static inline void rcu_read_unlock(void)
* rcu_read_lock_bh() - mark the beginning of an RCU-bh critical section
*
* This is equivalent of rcu_read_lock(), but also disables softirqs.
- * Note that synchronize_rcu() and friends may be used for the update
- * side, although synchronize_rcu_bh() is available as a wrapper in the
- * short term. Longer term, the _bh update-side API will be eliminated.
+ * Note that anything else that disables softirqs can also serve as
+ * an RCU read-side critical section.
*
* Note that rcu_read_lock_bh() and the matching rcu_read_unlock_bh()
* must occur in the same context, for example, it is illegal to invoke
@@ -705,10 +703,9 @@ static inline void rcu_read_unlock_bh(void)
/**
* rcu_read_lock_sched() - mark the beginning of a RCU-sched critical section
*
- * This is equivalent of rcu_read_lock(), but to be used when updates
- * are being done using call_rcu_sched() or synchronize_rcu_sched().
- * Read-side critical sections can also be introduced by anything that
- * disables preemption, including local_irq_disable() and friends.
+ * This is equivalent of rcu_read_lock(), but disables preemption.
+ * Read-side critical sections can also be introduced by anything else
+ * that disables preemption, including local_irq_disable() and friends.
*
* Note that rcu_read_lock_sched() and the matching rcu_read_unlock_sched()
* must occur in the same context, for example, it is illegal to invoke
--
2.17.1