linux-kernel - [PATCH] tracing: Use swap macro in update_max

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Date:   Fri, 9 Feb 2018 11:53:16 -0600
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Steven Rostedt <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...hat.com>
Cc:     linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: [PATCH] tracing: Use swap macro in update_max_tr

Make use of the swap macro and remove unnecessary variable _buf_.
This makes the code easier to read and maintain. Also, reduces the
stack usage.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>
---
 kernel/trace/trace.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5660853..6dcd740 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1351,8 +1351,6 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 void
 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
-	struct ring_buffer *buf;
-
 	if (tr->stop_count)
 		return;
 
@@ -1366,9 +1364,7 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 
 	arch_spin_lock(&tr->max_lock);
 
-	buf = tr->trace_buffer.buffer;
-	tr->trace_buffer.buffer = tr->max_buffer.buffer;
-	tr->max_buffer.buffer = buf;
+	swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
 
 	__update_max_tr(tr, tsk, cpu);
 	arch_spin_unlock(&tr->max_lock);
-- 
2.7.4