Commit 16fc9c60 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Remove rcu_state_p pointer to default rcu_state structure 



The rcu_state_p pointer references the default rcu_state structure,
that is, the one that call_rcu() uses, as opposed to call_rcu_bh()
and sometimes call_rcu_sched().  But there is now only one rcu_state
structure, so that one structure is by definition the default, which
means that the rcu_state_p pointer no longer serves any useful purpose.
This commit therefore removes it.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent da1df50d

kernel/rcu/tree.c

+12 −15
Original line number Diff line number Diff line
@@ -85,7 +85,6 @@ struct rcu_state rcu_state = { 
	.ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock),

};



static struct rcu_state *const rcu_state_p = &rcu_state;

static struct rcu_data __percpu *const rcu_data_p = &rcu_data;

LIST_HEAD(rcu_struct_flavors);
@@ -491,7 +490,7 @@ static int rcu_pending(void); 
 */

unsigned long rcu_get_gp_seq(void)

{

	return READ_ONCE(rcu_state_p->gp_seq);

	return READ_ONCE(rcu_state.gp_seq);

}

EXPORT_SYMBOL_GPL(rcu_get_gp_seq);
@@ -510,7 +509,7 @@ EXPORT_SYMBOL_GPL(rcu_sched_get_gp_seq); 
 */

unsigned long rcu_bh_get_gp_seq(void)

{

	return READ_ONCE(rcu_state_p->gp_seq);

	return READ_ONCE(rcu_state.gp_seq);

}

EXPORT_SYMBOL_GPL(rcu_bh_get_gp_seq);
@@ -522,7 +521,7 @@ EXPORT_SYMBOL_GPL(rcu_bh_get_gp_seq); 
 */

unsigned long rcu_exp_batches_completed(void)

{

	return rcu_state_p->expedited_sequence;

	return rcu_state.expedited_sequence;

}

EXPORT_SYMBOL_GPL(rcu_exp_batches_completed);
@@ -541,7 +540,7 @@ EXPORT_SYMBOL_GPL(rcu_exp_batches_completed_sched); 
 */

void rcu_force_quiescent_state(void)

{

	force_quiescent_state(rcu_state_p);

	force_quiescent_state(&rcu_state);

}

EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
@@ -550,7 +549,7 @@ EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); 
 */

void rcu_bh_force_quiescent_state(void)

{

	force_quiescent_state(rcu_state_p);

	force_quiescent_state(&rcu_state);

}

EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state);
@@ -611,7 +610,7 @@ void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags, 
	case RCU_FLAVOR:

	case RCU_BH_FLAVOR:

	case RCU_SCHED_FLAVOR:

		rsp = rcu_state_p;

		rsp = &rcu_state;

		break;

	default:

		break;
@@ -2292,7 +2291,6 @@ rcu_report_unblock_qs_rnp(struct rcu_state *rsp, 


	raw_lockdep_assert_held_rcu_node(rnp);

	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT)) ||

	    WARN_ON_ONCE(rsp != rcu_state_p) ||

	    WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||

	    rnp->qsmask != 0) {

		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -2604,7 +2602,6 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *rsp)) 
		raw_spin_lock_irqsave_rcu_node(rnp, flags);

		if (rnp->qsmask == 0) {

			if (!IS_ENABLED(CONFIG_PREEMPT) ||

			    rsp != rcu_state_p ||

			    rcu_preempt_blocked_readers_cgp(rnp)) {

				/*

				 * No point in scanning bits because they
@@ -2973,7 +2970,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func, 
 */

void call_rcu(struct rcu_head *head, rcu_callback_t func)

{

	__call_rcu(head, func, rcu_state_p, -1, 0);

	__call_rcu(head, func, &rcu_state, -1, 0);

}

EXPORT_SYMBOL_GPL(call_rcu);
@@ -3000,7 +2997,7 @@ EXPORT_SYMBOL_GPL(call_rcu_sched); 
void kfree_call_rcu(struct rcu_head *head,

		    rcu_callback_t func)

{

	__call_rcu(head, func, rcu_state_p, -1, 1);

	__call_rcu(head, func, &rcu_state, -1, 1);

}

EXPORT_SYMBOL_GPL(kfree_call_rcu);
@@ -3029,7 +3026,7 @@ unsigned long get_state_synchronize_rcu(void) 
	 * before the load from ->gp_seq.

	 */

	smp_mb();  /* ^^^ */

	return rcu_seq_snap(&rcu_state_p->gp_seq);

	return rcu_seq_snap(&rcu_state.gp_seq);

}

EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
@@ -3049,7 +3046,7 @@ EXPORT_SYMBOL_GPL(get_state_synchronize_rcu); 
 */

void cond_synchronize_rcu(unsigned long oldstate)

{

	if (!rcu_seq_done(&rcu_state_p->gp_seq, oldstate))

	if (!rcu_seq_done(&rcu_state.gp_seq, oldstate))

		synchronize_rcu();

	else

		smp_mb(); /* Ensure GP ends before subsequent accesses. */
@@ -3308,7 +3305,7 @@ static void _rcu_barrier(struct rcu_state *rsp) 
 */

void rcu_barrier_bh(void)

{

	_rcu_barrier(rcu_state_p);

	_rcu_barrier(&rcu_state);

}

EXPORT_SYMBOL_GPL(rcu_barrier_bh);
@@ -3322,7 +3319,7 @@ EXPORT_SYMBOL_GPL(rcu_barrier_bh); 
 */

void rcu_barrier(void)

{

	_rcu_barrier(rcu_state_p);

	_rcu_barrier(&rcu_state);

}

EXPORT_SYMBOL_GPL(rcu_barrier);

kernel/rcu/tree_exp.h

+1 −1
Original line number Diff line number Diff line
@@ -756,7 +756,7 @@ static void sync_sched_exp_online_cleanup(int cpu) 
 */

void synchronize_rcu_expedited(void)

{

	struct rcu_state *rsp = rcu_state_p;

	struct rcu_state *rsp = &rcu_state;



	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||

			 lock_is_held(&rcu_lock_map) ||

kernel/rcu/tree_plugin.h

+8 −8
Original line number Diff line number Diff line
@@ -381,7 +381,7 @@ void rcu_note_context_switch(bool preempt) 
	 */

	rcu_qs();

	if (rdp->deferred_qs)

		rcu_report_exp_rdp(rcu_state_p, rdp);

		rcu_report_exp_rdp(&rcu_state, rdp);

	trace_rcu_utilization(TPS("End context switch"));

	barrier(); /* Avoid RCU read-side critical sections leaking up. */

}
@@ -509,7 +509,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
	 * blocked-tasks list below.

	 */

	if (rdp->deferred_qs) {

		rcu_report_exp_rdp(rcu_state_p, rdp);

		rcu_report_exp_rdp(&rcu_state, rdp);

		if (!t->rcu_read_unlock_special.s) {

			local_irq_restore(flags);

			return;
@@ -566,7 +566,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
							 rnp->grplo,

							 rnp->grphi,

							 !!rnp->gp_tasks);

			rcu_report_unblock_qs_rnp(rcu_state_p, rnp, flags);

			rcu_report_unblock_qs_rnp(&rcu_state, rnp, flags);

		} else {

			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);

		}
@@ -580,7 +580,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags) 
		 * then we need to report up the rcu_node hierarchy.

		 */

		if (!empty_exp && empty_exp_now)

			rcu_report_exp_rnp(rcu_state_p, rnp, true);

			rcu_report_exp_rnp(&rcu_state, rnp, true);

	} else {

		local_irq_restore(flags);

	}
@@ -1300,7 +1300,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, 
	struct sched_param sp;

	struct task_struct *t;



	if (rcu_state_p != rsp)

	if (&rcu_state != rsp)

		return 0;



	if (!rcu_scheduler_fully_active || rcu_rnp_online_cpus(rnp) == 0)
@@ -1431,8 +1431,8 @@ static void __init rcu_spawn_boost_kthreads(void) 
	for_each_possible_cpu(cpu)

		per_cpu(rcu_cpu_has_work, cpu) = 0;

	BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));

	rcu_for_each_leaf_node(rcu_state_p, rnp)

		(void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);

	rcu_for_each_leaf_node(&rcu_state, rnp)

		(void)rcu_spawn_one_boost_kthread(&rcu_state, rnp);

}



static void rcu_prepare_kthreads(int cpu)
@@ -1442,7 +1442,7 @@ static void rcu_prepare_kthreads(int cpu) 


	/* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */

	if (rcu_scheduler_fully_active)

		(void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);

		(void)rcu_spawn_one_boost_kthread(&rcu_state, rnp);

}



#else /* #ifdef CONFIG_RCU_BOOST */