Commit 51f5f78a authored by Zqiang's avatar Zqiang Committed by Paul E. McKenney
Browse files

srcu: Make Tiny synchronize_srcu() check for readers 



This commit adds lockdep checks for illegal use of synchronize_srcu()
within same-type SRCU read-side critical sections and within normal
RCU read-side critical sections.  It also makes synchronize_srcu()
be a no-op during early boot.

These changes bring Tiny synchronize_srcu() into line with both Tree
synchronize_srcu() and Tiny synchronize_rcu().

Signed-off-by: default avatarZqiang <qiang1.zhang@intel.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Tested-by: default avatarJohn Ogness <john.ogness@linutronix.de>
parent 0cd7e350

kernel/rcu/srcutiny.c

+10 −0
Original line number Diff line number Diff line
@@ -197,6 +197,16 @@ void synchronize_srcu(struct srcu_struct *ssp) 
{

	struct rcu_synchronize rs;



	RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||

			lock_is_held(&rcu_bh_lock_map) ||

			lock_is_held(&rcu_lock_map) ||

			lock_is_held(&rcu_sched_lock_map),

			"Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");



	if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)

		return;



	might_sleep();

	init_rcu_head_on_stack(&rs.head);

	init_completion(&rs.completion);

	call_srcu(ssp, &rs.head, wakeme_after_rcu);