Commit cfeac397 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Remove unused "cpu" parameter from rcu_report_qs_rdp() 



The "cpu" parameter to rcu_report_qs_rdp() is not used, with rdp->cpu
being used instead.  Furtheremore, every call to rcu_report_qs_rdp()
invokes it on rdp->cpu.  This commit therefore removes this unused "cpu"
parameter and converts a check of rdp->cpu against smp_processor_id()
to a WARN_ON_ONCE().

Reported-by: default avatarJann Horn <jannh@google.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent aa40c138

kernel/rcu/tree.c

+4 −4
Original line number Diff line number Diff line
@@ -2240,7 +2240,7 @@ rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) 
 * structure.  This must be called from the specified CPU.

 */

static void

rcu_report_qs_rdp(int cpu, struct rcu_data *rdp)

rcu_report_qs_rdp(struct rcu_data *rdp)

{

	unsigned long flags;

	unsigned long mask;
@@ -2249,6 +2249,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_data *rdp) 
			       rcu_segcblist_is_offloaded(&rdp->cblist);

	struct rcu_node *rnp;



	WARN_ON_ONCE(rdp->cpu != smp_processor_id());

	rnp = rdp->mynode;

	raw_spin_lock_irqsave_rcu_node(rnp, flags);

	if (rdp->cpu_no_qs.b.norm || rdp->gp_seq != rnp->gp_seq ||
@@ -2265,7 +2266,6 @@ rcu_report_qs_rdp(int cpu, struct rcu_data *rdp) 
		return;

	}

	mask = rdp->grpmask;

	if (rdp->cpu == smp_processor_id())

	rdp->core_needs_qs = false;

	if ((rnp->qsmask & mask) == 0) {

		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -2315,7 +2315,7 @@ rcu_check_quiescent_state(struct rcu_data *rdp) 
	 * Tell RCU we are done (but rcu_report_qs_rdp() will be the

	 * judge of that).

	 */

	rcu_report_qs_rdp(rdp->cpu, rdp);

	rcu_report_qs_rdp(rdp);

}



/*

kernel/rcu/tree_plugin.h

+2 −2
Original line number Diff line number Diff line
@@ -461,7 +461,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
	t->rcu_read_unlock_special.s = 0;

	if (special.b.need_qs) {

		if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) {

			rcu_report_qs_rdp(rdp->cpu, rdp);

			rcu_report_qs_rdp(rdp);

			udelay(rcu_unlock_delay);

		} else {

			rcu_qs();
@@ -791,7 +791,7 @@ void rcu_read_unlock_strict(void) 
	   irqs_disabled() || preempt_count() || !rcu_state.gp_kthread)

		return;

	rdp = this_cpu_ptr(&rcu_data);

	rcu_report_qs_rdp(rdp->cpu, rdp);

	rcu_report_qs_rdp(rdp);

	udelay(rcu_unlock_delay);

}

EXPORT_SYMBOL_GPL(rcu_read_unlock_strict);

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