rcu: Remove rsp parameter from no-CBs CPU functions

There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to
RCU's functions.  This commit therefore removes the rsp parameter
from rcu_nocb_cpu_needs_barrier(), rcu_spawn_one_nocb_kthread(),
rcu_organize_nocb_kthreads(), rcu_nocb_cpu_needs_barrier(), and
rcu_nohz_full_cpu().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/tree.c

@@ -3095,7 +3095,7 @@ static int rcu_pending(void)
 	check_cpu_stall(rdp);
 
 	/* Is this CPU a NO_HZ_FULL CPU that should ignore RCU? */
-	if (rcu_nohz_full_cpu(&rcu_state))
+	if (rcu_nohz_full_cpu())
 		return 0;
 
 	/* Is the RCU core waiting for a quiescent state from this CPU? */
@@ -3246,7 +3246,7 @@ static void _rcu_barrier(void)
 			continue;
 		rdp = per_cpu_ptr(&rcu_data, cpu);
 		if (rcu_is_nocb_cpu(cpu)) {
-			if (!rcu_nocb_cpu_needs_barrier(rsp, cpu)) {
+			if (!rcu_nocb_cpu_needs_barrier(cpu)) {
 				_rcu_barrier_trace(TPS("OfflineNoCB"), cpu,
 						   rsp->barrier_sequence);
 			} else {

kernel/rcu/tree.h

@@ -476,7 +476,7 @@ static void print_cpu_stall_info(int cpu);
 static void print_cpu_stall_info_end(void);
 static void zero_cpu_stall_ticks(struct rcu_data *rdp);
 static void increment_cpu_stall_ticks(void);
-static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu);
+static bool rcu_nocb_cpu_needs_barrier(int cpu);
 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
 static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
 static void rcu_init_one_nocb(struct rcu_node *rnp);
@@ -491,11 +491,11 @@ static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
 static void rcu_spawn_all_nocb_kthreads(int cpu);
 static void __init rcu_spawn_nocb_kthreads(void);
 #ifdef CONFIG_RCU_NOCB_CPU
-static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp);
+static void __init rcu_organize_nocb_kthreads(void);
 #endif /* #ifdef CONFIG_RCU_NOCB_CPU */
 static bool init_nocb_callback_list(struct rcu_data *rdp);
 static void rcu_bind_gp_kthread(void);
-static bool rcu_nohz_full_cpu(struct rcu_state *rsp);
+static bool rcu_nohz_full_cpu(void);
 static void rcu_dynticks_task_enter(void);
 static void rcu_dynticks_task_exit(void);
 

kernel/rcu/tree_plugin.h

@@ -1960,7 +1960,7 @@ static void wake_nocb_leader_defer(struct rcu_data *rdp, int waketype,
  * Does the specified CPU need an RCU callback for the specified flavor
  * of rcu_barrier()?
  */
-static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu)
+static bool rcu_nocb_cpu_needs_barrier(int cpu)
 {
 	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
 	unsigned long ret;
@@ -2424,7 +2424,7 @@ void __init rcu_init_nohz(void)
 	for_each_rcu_flavor(rsp) {
 		for_each_cpu(cpu, rcu_nocb_mask)
 			init_nocb_callback_list(per_cpu_ptr(&rcu_data, cpu));
-		rcu_organize_nocb_kthreads(rsp);
+		rcu_organize_nocb_kthreads();
 	}
 }
 
@@ -2444,7 +2444,7 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
  * brought online out of order, this can require re-organizing the
  * leader-follower relationships.
  */
-static void rcu_spawn_one_nocb_kthread(struct rcu_state *rsp, int cpu)
+static void rcu_spawn_one_nocb_kthread(int cpu)
 {
 	struct rcu_data *rdp;
 	struct rcu_data *rdp_last;
@@ -2481,7 +2481,7 @@ static void rcu_spawn_one_nocb_kthread(struct rcu_state *rsp, int cpu)
 
 	/* Spawn the kthread for this CPU and RCU flavor. */
 	t = kthread_run(rcu_nocb_kthread, rdp_spawn,
-			"rcuo%c/%d", rsp->abbr, cpu);
+			"rcuo%c/%d", rcu_state.abbr, cpu);
 	BUG_ON(IS_ERR(t));
 	WRITE_ONCE(rdp_spawn->nocb_kthread, t);
 }
@@ -2496,7 +2496,7 @@ static void rcu_spawn_all_nocb_kthreads(int cpu)
 
 	if (rcu_scheduler_fully_active)
 		for_each_rcu_flavor(rsp)
-			rcu_spawn_one_nocb_kthread(rsp, cpu);
+			rcu_spawn_one_nocb_kthread(cpu);
 }
 
 /*
@@ -2520,7 +2520,7 @@ module_param(rcu_nocb_leader_stride, int, 0444);
 /*
  * Initialize leader-follower relationships for all no-CBs CPU.
  */
-static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp)
+static void __init rcu_organize_nocb_kthreads(void)
 {
 	int cpu;
 	int ls = rcu_nocb_leader_stride;
@@ -2579,7 +2579,7 @@ static bool init_nocb_callback_list(struct rcu_data *rdp)
 
 #else /* #ifdef CONFIG_RCU_NOCB_CPU */
 
-static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu)
+static bool rcu_nocb_cpu_needs_barrier(int cpu)
 {
 	WARN_ON_ONCE(1); /* Should be dead code. */
 	return false;
@@ -2648,12 +2648,12 @@ static bool init_nocb_callback_list(struct rcu_data *rdp)
  * This code relies on the fact that all NO_HZ_FULL CPUs are also
  * CONFIG_RCU_NOCB_CPU CPUs.
  */
-static bool rcu_nohz_full_cpu(struct rcu_state *rsp)
+static bool rcu_nohz_full_cpu(void)
 {
 #ifdef CONFIG_NO_HZ_FULL
 	if (tick_nohz_full_cpu(smp_processor_id()) &&
 	    (!rcu_gp_in_progress() ||
-	     ULONG_CMP_LT(jiffies, READ_ONCE(rsp->gp_start) + HZ)))
+	     ULONG_CMP_LT(jiffies, READ_ONCE(rcu_state.gp_start) + HZ)))
 		return true;
 #endif /* #ifdef CONFIG_NO_HZ_FULL */
 	return false;