rcu: Eliminate callback-invocation/invocation 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_do_batch(), invoke_rcu_callbacks(), and __call_rcu().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8891537..46bdb52 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2467,14 +2467,13 @@ static void rcu_do_batch(struct rcu_data *rdp)
        struct rcu_head *rhp;
        struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl);
        long bl, count;
-       struct rcu_state *rsp = &rcu_state;
 
        /* If no callbacks are ready, just return. */
        if (!rcu_segcblist_ready_cbs(&rdp->cblist)) {
-               trace_rcu_batch_start(rsp->name,
+               trace_rcu_batch_start(rcu_state.name,
                                      rcu_segcblist_n_lazy_cbs(&rdp->cblist),
                                      rcu_segcblist_n_cbs(&rdp->cblist), 0);
-               trace_rcu_batch_end(rsp->name, 0,
+               trace_rcu_batch_end(rcu_state.name, 0,
                                    !rcu_segcblist_empty(&rdp->cblist),
                                    need_resched(), is_idle_task(current),
                                    rcu_is_callbacks_kthread());
@@ -2489,7 +2488,8 @@ static void rcu_do_batch(struct rcu_data *rdp)
        local_irq_save(flags);
        WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
        bl = rdp->blimit;
-       trace_rcu_batch_start(rsp->name, rcu_segcblist_n_lazy_cbs(&rdp->cblist),
+       trace_rcu_batch_start(rcu_state.name,
+                             rcu_segcblist_n_lazy_cbs(&rdp->cblist),
                              rcu_segcblist_n_cbs(&rdp->cblist), bl);
        rcu_segcblist_extract_done_cbs(&rdp->cblist, &rcl);
        local_irq_restore(flags);
@@ -2498,7 +2498,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
        rhp = rcu_cblist_dequeue(&rcl);
        for (; rhp; rhp = rcu_cblist_dequeue(&rcl)) {
                debug_rcu_head_unqueue(rhp);
-               if (__rcu_reclaim(rsp->name, rhp))
+               if (__rcu_reclaim(rcu_state.name, rhp))
                        rcu_cblist_dequeued_lazy(&rcl);
                /*
                 * Stop only if limit reached and CPU has something to do.
@@ -2512,7 +2512,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
 
        local_irq_save(flags);
        count = -rcl.len;
-       trace_rcu_batch_end(rsp->name, count, !!rcl.head, need_resched(),
+       trace_rcu_batch_end(rcu_state.name, count, !!rcl.head, need_resched(),
                            is_idle_task(current), rcu_is_callbacks_kthread());
 
        /* Update counts and requeue any remaining callbacks. */
@@ -2528,7 +2528,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
        /* Reset ->qlen_last_fqs_check trigger if enough CBs have drained. */
        if (count == 0 && rdp->qlen_last_fqs_check != 0) {
                rdp->qlen_last_fqs_check = 0;
-               rdp->n_force_qs_snap = rsp->n_force_qs;
+               rdp->n_force_qs_snap = rcu_state.n_force_qs;
        } else if (count < rdp->qlen_last_fqs_check - qhimark)
                rdp->qlen_last_fqs_check = count;
 
@@ -2764,11 +2764,9 @@ static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused
  */
 static void invoke_rcu_callbacks(struct rcu_data *rdp)
 {
-       struct rcu_state *rsp = &rcu_state;
-
        if (unlikely(!READ_ONCE(rcu_scheduler_fully_active)))
                return;
-       if (likely(!rsp->boost)) {
+       if (likely(!rcu_state.boost)) {
                rcu_do_batch(rdp);
                return;
        }
@@ -2844,7 +2842,6 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func, int cpu, bool lazy)
 {
        unsigned long flags;
        struct rcu_data *rdp;
-       struct rcu_state __maybe_unused *rsp = &rcu_state;
 
        /* Misaligned rcu_head! */
        WARN_ON_ONCE((unsigned long)head & (sizeof(void *) - 1));
@@ -2893,11 +2890,12 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func, int cpu, bool lazy)
                rcu_idle_count_callbacks_posted();
 
        if (__is_kfree_rcu_offset((unsigned long)func))
-               trace_rcu_kfree_callback(rsp->name, head, (unsigned long)func,
+               trace_rcu_kfree_callback(rcu_state.name, head,
+                                        (unsigned long)func,
                                         rcu_segcblist_n_lazy_cbs(&rdp->cblist),
                                         rcu_segcblist_n_cbs(&rdp->cblist));
        else
-               trace_rcu_callback(rsp->name, head,
+               trace_rcu_callback(rcu_state.name, head,
                                   rcu_segcblist_n_lazy_cbs(&rdp->cblist),
                                   rcu_segcblist_n_cbs(&rdp->cblist));