Commit eb7a6653 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Eliminate initialization-time use of rsp 



Now that there is only one rcu_state structure, there is less point in
maintaining a pointer to it.  This commit therefore replaces rsp with
&rcu_state in rcu_cpu_starting() and rcu_init_one().

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent ec9f5835

kernel/rcu/tree.c

+12 −13
Original line number Diff line number Diff line
@@ -3455,7 +3455,6 @@ void rcu_cpu_starting(unsigned int cpu) 
	unsigned long oldmask;

	struct rcu_data *rdp;

	struct rcu_node *rnp;

	struct rcu_state *rsp = &rcu_state;



	if (per_cpu(rcu_cpu_started, cpu))

		return;
@@ -3472,10 +3471,10 @@ void rcu_cpu_starting(unsigned int cpu) 
	oldmask ^= rnp->expmaskinitnext;

	nbits = bitmap_weight(&oldmask, BITS_PER_LONG);

	/* Allow lockless access for expedited grace periods. */

	smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */

	smp_store_release(&rcu_state.ncpus, rcu_state.ncpus + nbits); /* ^^^ */

	rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */

	rdp->rcu_onl_gp_seq = READ_ONCE(rsp->gp_seq);

	rdp->rcu_onl_gp_flags = READ_ONCE(rsp->gp_flags);

	rdp->rcu_onl_gp_seq = READ_ONCE(rcu_state.gp_seq);

	rdp->rcu_onl_gp_flags = READ_ONCE(rcu_state.gp_flags);

	if (rnp->qsmask & mask) { /* RCU waiting on incoming CPU? */

		/* Report QS -after- changing ->qsmaskinitnext! */

		rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
@@ -3667,7 +3666,6 @@ static void __init rcu_init_one(void) 
	int i;

	int j;

	struct rcu_node *rnp;

	struct rcu_state *rsp = &rcu_state;



	BUILD_BUG_ON(RCU_NUM_LVLS > ARRAY_SIZE(buf));  /* Fix buf[] init! */
@@ -3678,14 +3676,15 @@ static void __init rcu_init_one(void) 
	/* Initialize the level-tracking arrays. */



	for (i = 1; i < rcu_num_lvls; i++)

		rsp->level[i] = rsp->level[i - 1] + num_rcu_lvl[i - 1];

		rcu_state.level[i] =

			rcu_state.level[i - 1] + num_rcu_lvl[i - 1];

	rcu_init_levelspread(levelspread, num_rcu_lvl);



	/* Initialize the elements themselves, starting from the leaves. */



	for (i = rcu_num_lvls - 1; i >= 0; i--) {

		cpustride *= levelspread[i];

		rnp = rsp->level[i];

		rnp = rcu_state.level[i];

		for (j = 0; j < num_rcu_lvl[i]; j++, rnp++) {

			raw_spin_lock_init(&ACCESS_PRIVATE(rnp, lock));

			lockdep_set_class_and_name(&ACCESS_PRIVATE(rnp, lock),
@@ -3693,9 +3692,9 @@ static void __init rcu_init_one(void) 
			raw_spin_lock_init(&rnp->fqslock);

			lockdep_set_class_and_name(&rnp->fqslock,

						   &rcu_fqs_class[i], fqs[i]);

			rnp->gp_seq = rsp->gp_seq;

			rnp->gp_seq_needed = rsp->gp_seq;

			rnp->completedqs = rsp->gp_seq;

			rnp->gp_seq = rcu_state.gp_seq;

			rnp->gp_seq_needed = rcu_state.gp_seq;

			rnp->completedqs = rcu_state.gp_seq;

			rnp->qsmask = 0;

			rnp->qsmaskinit = 0;

			rnp->grplo = j * cpustride;
@@ -3709,7 +3708,7 @@ static void __init rcu_init_one(void) 
			} else {

				rnp->grpnum = j % levelspread[i - 1];

				rnp->grpmask = 1UL << rnp->grpnum;

				rnp->parent = rsp->level[i - 1] +

				rnp->parent = rcu_state.level[i - 1] +

					      j / levelspread[i - 1];

			}

			rnp->level = i;
@@ -3723,8 +3722,8 @@ static void __init rcu_init_one(void) 
		}

	}



	init_swait_queue_head(&rsp->gp_wq);

	init_swait_queue_head(&rsp->expedited_wq);

	init_swait_queue_head(&rcu_state.gp_wq);

	init_swait_queue_head(&rcu_state.expedited_wq);

	rnp = rcu_first_leaf_node();

	for_each_possible_cpu(i) {

		while (i > rnp->grphi)