Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cc5f730b authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Paul E. McKenney
Browse files

locking/percpu-rwsem: Clean up the lockdep annotations in percpu_down_read() 



Based on Peter Zijlstra's earlier patch.

Change percpu_down_read() to use __down_read(), this way we can
do rwsem_acquire_read() unconditionally at the start to make this
code more symmetric and clean.

Originally-From: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent f324a763

kernel/locking/percpu-rwsem.c

+5 −5
Original line number Diff line number Diff line
@@ -70,14 +70,14 @@ static bool update_fast_ctr(struct percpu_rw_semaphore *brw, unsigned int val) 
void percpu_down_read(struct percpu_rw_semaphore *brw)

{

	might_sleep();

	if (likely(update_fast_ctr(brw, +1))) {

	rwsem_acquire_read(&brw->rw_sem.dep_map, 0, 0, _RET_IP_);



	if (likely(update_fast_ctr(brw, +1)))

		return;

	}



	down_read(&brw->rw_sem);

	/* Avoid rwsem_acquire_read() and rwsem_release() */

	__down_read(&brw->rw_sem);

	atomic_inc(&brw->slow_read_ctr);

	/* avoid up_read()->rwsem_release() */

	__up_read(&brw->rw_sem);

}

EXPORT_SYMBOL_GPL(percpu_down_read);