[PATCH tip/core/rcu 27/30] rcu-tasks: Fix synchronize_rcu_tasks_trace() header comment

paulmck
2020-06-23T00:30:58Z

The synchronize_rcu_tasks_trace() header comment incorrectly claims that
any number of things delimit RCU Tasks Trace read-side critical sections,
when in fact only rcu_read_lock_trace() and rcu_read_unlock_trace() do so.
This commit therefore fixes this comment, and, while in the area, fixes
a typo in the rcu_read_lock_trace() header comment.

Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
include/linux/rcupdate_trace.h | 4 ++--
kernel/rcu/tasks.h | 9 ++++-----
2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h
index 4c25a41..d9015aa 100644
--- a/include/linux/rcupdate_trace.h
+++ b/include/linux/rcupdate_trace.h
@@ -36,8 +36,8 @@ void rcu_read_unlock_trace_special(struct task_struct *t, int nesting);
/**
* rcu_read_lock_trace - mark beginning of RCU-trace read-side critical section
*
- * When synchronize_rcu_trace() is invoked by one task, then that task
- * is guaranteed to block until all other tasks exit their read-side
+ * When synchronize_rcu_tasks_trace() is invoked by one task, then that
+ * task is guaranteed to block until all other tasks exit their read-side
* critical sections. Similarly, if call_rcu_trace() is invoked on one
* task while other tasks are within RCU read-side critical sections,
* invocation of the corresponding RCU callback is deferred until after
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index ce23f6c..a77298c 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1118,11 +1118,10 @@ EXPORT_SYMBOL_GPL(call_rcu_tasks_trace);
* synchronize_rcu_tasks_trace - wait for a trace rcu-tasks grace period
*
* Control will return to the caller some time after a trace rcu-tasks
- * grace period has elapsed, in other words after all currently
- * executing rcu-tasks read-side critical sections have elapsed. These
- * read-side critical sections are delimited by calls to schedule(),
- * cond_resched_tasks_rcu_qs(), userspace execution, and (in theory,
- * anyway) cond_resched().
+ * grace period has elapsed, in other words after all currently executing
+ * rcu-tasks read-side critical sections have elapsed. These read-side
+ * critical sections are delimited by calls to rcu_read_lock_trace()
+ * and rcu_read_unlock_trace().
*
* This is a very specialized primitive, intended only for a few uses in
* tracing and other situations requiring manipulation of function preambles
--
2.9.5