Commit 03bd2983 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Use lockdep rather than comment to enforce lock held 



The rcu_preempt_check_blocked_tasks() function has a comment
that states that the rcu_node structure's ->lock must be held,
which might be informative, but which carries little weight if
not read.  This commit therefore removes this comment in favor of
raw_lockdep_assert_held_rcu_node(), which will complain quite
visibly if the required lock is not held.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 6935c398

kernel/rcu/tree_plugin.h

+2 −2
Original line number Diff line number Diff line
@@ -648,8 +648,7 @@ static void rcu_read_unlock_special(struct task_struct *t) 
 * Check that the list of blocked tasks for the newly completed grace

 * period is in fact empty.  It is a serious bug to complete a grace

 * period that still has RCU readers blocked!  This function must be

 * invoked -before- updating this rnp's ->gp_seq, and the rnp's ->lock

 * must be held by the caller.

 * invoked -before- updating this rnp's ->gp_seq.

 *

 * Also, if there are blocked tasks on the list, they automatically

 * block the newly created grace period, so set up ->gp_tasks accordingly.
@@ -659,6 +658,7 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) 
	struct task_struct *t;



	RCU_LOCKDEP_WARN(preemptible(), "rcu_preempt_check_blocked_tasks() invoked with preemption enabled!!!\n");

	raw_lockdep_assert_held_rcu_node(rnp);

	if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)))

		dump_blkd_tasks(rnp, 10);

	if (rcu_preempt_has_tasks(rnp) &&

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