linux-kernel - [PATCH] RCU: Adjust the comment of function rcu_is

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Message-ID: <5bbafe54.1c69fb81.954a9.deae@mx.google.com>
Date:   Mon,  8 Oct 2018 06:50:41 +0000
From:   zhouzhouyi@...il.com
To:     paulmck@...ux.vnet.ibm.com, josh@...htriplett.org,
        rostedt@...dmis.org, mathieu.desnoyers@...icios.com,
        jiangshanlai@...il.com, linux-kernel@...r.kernel.org
Cc:     Zhouyi Zhou <zhouzhouyi@...il.com>
Subject: [PATCH] RCU: Adjust the comment of function rcu_is_watching

From: Zhouyi Zhou <zhouzhouyi@...il.com>

Because RCU avoids interrupting idle CPUs, rcu_is_watching is used to
test whether or not it is currently legal to run RCU read-side 
critical sections on this CPU. 

First sentence and last sentence of current comment for rcu_is_watching
have opposite meaning of what is expected.  

Signed-off-by: Zhouyi Zhou <zhouzhouyi@...il.com>
---
 kernel/rcu/tree.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 0b760c1..adb04ea 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1010,12 +1010,12 @@ void rcu_irq_enter_irqson(void)
 }
 
 /**
- * rcu_is_watching - see if RCU thinks that the current CPU is idle
+ * rcu_is_watching - see if RCU thinks that the current CPU is not idle
  *
  * Return true if RCU is watching the running CPU, which means that this
  * CPU can safely enter RCU read-side critical sections.  In other words,
- * if the current CPU is in its idle loop and is neither in an interrupt
- * or NMI handler, return true.
+ * if the current CPU is not in its idle loop or is in an interrupt or
+ * NMI handler, return true.
  */
 bool notrace rcu_is_watching(void)
 {
-- 
2.1.4