[PATCH RFC tip/core/rcu 11/15] tracepoint: Remove smp_read_barrier_depends() from comment

From: Paul E. McKenney
Date: Mon Oct 09 2017 - 20:24:53 EST


The comment in tracepoint_add_func() mentions smp_read_barrier_depends(),
whose use should be quite restricted. This commit updates the comment
to instead mention the smp_store_release() and rcu_dereference_sched()
that the current code actually uses.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/tracepoint.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 685c50ae6300..671b13457387 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -212,11 +212,10 @@ static int tracepoint_add_func(struct tracepoint *tp,
}

/*
- * rcu_assign_pointer has a smp_wmb() which makes sure that the new
- * probe callbacks array is consistent before setting a pointer to it.
- * This array is referenced by __DO_TRACE from
- * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
- * is used.
+ * rcu_assign_pointer has as smp_store_release() which makes sure
+ * that the new probe callbacks array is consistent before setting
+ * a pointer to it. This array is referenced by __DO_TRACE from
+ * include/linux/tracepoint.h using rcu_dereference_sched().
*/
rcu_assign_pointer(tp->funcs, tp_funcs);
if (!static_key_enabled(&tp->key))
--
2.5.2