rcu: Remove "cpu" argument to rcu_check_callbacks()

The "cpu" argument was kept around on the off-chance that RCU might
offload scheduler-clock interrupts.  However, this offload approach
has been replaced by NO_HZ_FULL, which offloads -all- RCU processing
from qualifying CPUs.  It is therefore time to remove the "cpu" argument
to rcu_check_callbacks(), which this commit does.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>

4 files changed, 6 insertions, 7 deletions

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a4a819ffb2d1..b4ad275d90d0 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -260,7 +260,7 @@ static inline int rcu_preempt_depth(void)
 void rcu_init(void);
 void rcu_sched_qs(void);
 void rcu_bh_qs(void);
-void rcu_check_callbacks(int cpu, int user);
+void rcu_check_callbacks(int user);
 struct notifier_block;
 void rcu_idle_enter(void);
 void rcu_idle_exit(void);
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index c0623fc47125..01570c68d237 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -247,7 +247,7 @@ void rcu_bh_qs(void)
  * be called from hardirq context.  It is normally called from the
  * scheduling-clock interrupt.
  */
-void rcu_check_callbacks(int cpu, int user)
+void rcu_check_callbacks(int user)
 {
         RCU_TRACE(check_cpu_stalls());
         if (user || rcu_is_cpu_rrupt_from_idle())
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index ab6fcfb4fe11..3107811bba69 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2388,7 +2388,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
  * invoked from the scheduling-clock interrupt.  If rcu_pending returns
  * false, there is no point in invoking rcu_check_callbacks().
  */
-void rcu_check_callbacks(int cpu, int user)
+void rcu_check_callbacks(int user)
 {
         trace_rcu_utilization(TPS("Start scheduler-tick"));
         increment_cpu_stall_ticks();
@@ -2420,8 +2420,8 @@ void rcu_check_callbacks(int cpu, int user)
 
                 rcu_bh_qs();
         }
-        rcu_preempt_check_callbacks(cpu);
-        if (rcu_pending(cpu))
+        rcu_preempt_check_callbacks(smp_processor_id());
+        if (rcu_pending(smp_processor_id()))
                 invoke_rcu_core();
         if (user)
                 rcu_note_voluntary_context_switch(current);
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 3260ffdb368f..2d3f5c504939 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1377,12 +1377,11 @@ unsigned long get_next_timer_interrupt(unsigned long now)
 void update_process_times(int user_tick)
 {
         struct task_struct *p = current;
-        int cpu = smp_processor_id();
 
         /* Note: this timer irq context must be accounted for as well. */
         account_process_tick(p, user_tick);
         run_local_timers();
-        rcu_check_callbacks(cpu, user_tick);
+        rcu_check_callbacks(user_tick);
 #ifdef CONFIG_IRQ_WORK
         if (in_irq())
                 irq_work_tick();