[PATCH tip/core/rcu 11/20] doc: rcu: Add more rationale for using rcu_read_lock_sched in checklist

From: Paul E. McKenney
Date: Sun Nov 11 2018 - 14:56:58 EST


From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx>

This commit explains why rcu_read_lock_sched is better than using
preempt_disable.

Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
---
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
--
2.17.1