From: Joel Fernandes (Google) Date: Fri, 5 Oct 2018 23:18:11 +0000 (-0700) Subject: doc: rcu: Add more rationale for using rcu_read_lock_sched in checklist X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=090c1685fd628a8c191d77b5267a7dc226246a5b;p=linux.git doc: rcu: Add more rationale for using rcu_read_lock_sched in checklist This commit explains why rcu_read_lock_sched is better than using preempt_disable. Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney --- diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt index 49747717d9057..8860ab2a897ae 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