rcu: Eliminate redundant rcu_sysidle_state variable

Now that we have rcu_state_p, which references rcu_preempt_state for
TREE_PREEMPT_RCU and rcu_sched_state for TREE_RCU, we don't need a
separate rcu_sysidle_state variable.  This commit therefore eliminates
rcu_preempt_state in favor of rcu_state_p.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

1 files changed, 6 insertions, 17 deletions

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 39e68bcf6d83..3ddad4fb11a8 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2690,16 +2690,6 @@ static void __maybe_unused rcu_kick_nohz_cpu(int cpu)
 
 #ifdef CONFIG_NO_HZ_FULL_SYSIDLE
 
-/*
- * Define RCU flavor that holds sysidle state.  This needs to be the
- * most active flavor of RCU.
- */
-#ifdef CONFIG_PREEMPT_RCU
-static struct rcu_state *rcu_sysidle_state = &rcu_preempt_state;
-#else /* #ifdef CONFIG_PREEMPT_RCU */
-static struct rcu_state *rcu_sysidle_state = &rcu_sched_state;
-#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
-
 static int full_sysidle_state;          /* Current system-idle state. */
 #define RCU_SYSIDLE_NOT         0       /* Some CPU is not idle. */
 #define RCU_SYSIDLE_SHORT       1       /* All CPUs idle for brief period. */
@@ -2841,7 +2831,7 @@ static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle,
          * not the flavor of RCU that tracks sysidle state, or if this
          * is an offline or the timekeeping CPU, nothing to do.
          */
-        if (!*isidle || rdp->rsp != rcu_sysidle_state ||
+        if (!*isidle || rdp->rsp != rcu_state_p ||
             cpu_is_offline(rdp->cpu) || rdp->cpu == tick_do_timer_cpu)
                 return;
         if (rcu_gp_in_progress(rdp->rsp))
@@ -2867,7 +2857,7 @@ static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle,
  */
 static bool is_sysidle_rcu_state(struct rcu_state *rsp)
 {
-        return rsp == rcu_sysidle_state;
+        return rsp == rcu_state_p;
 }
 
 /*
@@ -2945,7 +2935,7 @@ static void rcu_sysidle_cancel(void)
 static void rcu_sysidle_report(struct rcu_state *rsp, int isidle,
                                unsigned long maxj, bool gpkt)
 {
-        if (rsp != rcu_sysidle_state)
+        if (rsp != rcu_state_p)
                 return;  /* Wrong flavor, ignore. */
         if (gpkt && nr_cpu_ids <= CONFIG_NO_HZ_FULL_SYSIDLE_SMALL)
                 return;  /* Running state machine from timekeeping CPU. */
@@ -3014,13 +3004,12 @@ bool rcu_sys_is_idle(void)
 
                         /* Scan all the CPUs looking for nonidle CPUs. */
                         for_each_possible_cpu(cpu) {
-                                rdp = per_cpu_ptr(rcu_sysidle_state->rda, cpu);
+                                rdp = per_cpu_ptr(rcu_state_p->rda, cpu);
                                 rcu_sysidle_check_cpu(rdp, &isidle, &maxj);
                                 if (!isidle)
                                         break;
                         }
-                        rcu_sysidle_report(rcu_sysidle_state,
-                                           isidle, maxj, false);
+                        rcu_sysidle_report(rcu_state_p, isidle, maxj, false);
                         oldrss = rss;
                         rss = ACCESS_ONCE(full_sysidle_state);
                 }
@@ -3047,7 +3036,7 @@ bool rcu_sys_is_idle(void)
          * provided by the memory allocator.
          */
         if (nr_cpu_ids > CONFIG_NO_HZ_FULL_SYSIDLE_SMALL &&
-            !rcu_gp_in_progress(rcu_sysidle_state) &&
+            !rcu_gp_in_progress(rcu_state_p) &&
             !rsh.inuse && xchg(&rsh.inuse, 1) == 0)
                 call_rcu(&rsh.rh, rcu_sysidle_cb);
         return false;