linux-kernel - [PATCH RFC 2/5] doc: rcu: Add more rationale for using rcu_read_lock

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Message-Id: <20181005231815.170433-3-joel@joelfernandes.org>
Date:   Fri,  5 Oct 2018 16:18:11 -0700
From:   "Joel Fernandes (Google)" <joel@...lfernandes.org>
To:     linux-kernel@...r.kernel.org
Cc:     "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        Jonathan Corbet <corbet@....net>,
        Josh Triplett <josh@...htriplett.org>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        linux-doc@...r.kernel.org,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        "Paul E. McKenney" <paulmck@...ux.ibm.com>,
        Steven Rostedt <rostedt@...dmis.org>, pantin@...gle.com
Subject: [PATCH RFC 2/5] doc: rcu: Add more rationale for using rcu_read_lock_sched in checklist

It could be clarified better why rcu_read_lock_sched is better than
using preempt_disable, add the same.

Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
 Documentation/RCU/checklist.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 49747717d905..8860ab2a897a 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -63,7 +63,7 @@ over a rather long period of time, but improvements are always welcome!
 	pointer must be covered by rcu_read_lock(), rcu_read_lock_bh(),
 	rcu_read_lock_sched(), or by the appropriate update-side lock.
 	Disabling of preemption can serve as rcu_read_lock_sched(), but
-	is less readable.
+	is less readable and prevents lockdep from detecting locking issues.
 
 	Letting RCU-protected pointers "leak" out of an RCU read-side
 	critical section is every bid as bad as letting them leak out
-- 
2.19.0.605.g01d371f741-goog