Re: [PATCH v3 09/14] cgroup/cpuset: Remove redundant rcu_read_lock/unlock() in spin_lock
From: Tejun Heo <tj@kernel.org>
Date: 2025-09-16 18:37:16
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On Tue, Sep 16, 2025 at 12:47:30PM +0800, pengdonglin wrote:
From: pengdonglin <redacted>
Since commit a8bb74acd8efe ("rcu: Consolidate RCU-sched update-side function definitions")
there is no difference between rcu_read_lock(), rcu_read_lock_bh() and
rcu_read_lock_sched() in terms of RCU read section and the relevant grace
period. That means that spin_lock(), which implies rcu_read_lock_sched(),
also implies rcu_read_lock().
There is no need no explicitly start a RCU read section if one has already
been started implicitly by spin_lock().
Simplify the code and remove the inner rcu_read_lock() invocation.
Cc: Waiman Long <longman@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: pengdonglin <redacted>
Signed-off-by: pengdonglin <redacted>Applied to cgroup/for-6.18. Thanks. -- tejun