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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index ce5fb177a0f7cb4244aa758a536db388d3d61aef..5e3a3001a50d64851d1a5b97115f4635109911ca 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -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)