rcu: Remove "cpu" argument to rcu_needs_cpu()

The "cpu" argument to rcu_needs_cpu() is always the current CPU, so drop
it.  This in turn allows the "cpu" argument to rcu_cpu_has_callbacks()
to be removed, which allows the uses of "cpu" in both functions to be
replaced with a this_cpu_ptr().  Again, the anticipated cross-CPU uses
of these functions has been replaced by NO_HZ_FULL.

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

3 files changed, 9 insertions, 9 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b591f1459240..d678a98caf1d 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3159,7 +3159,7 @@ static int rcu_pending(void)
  * non-NULL, store an indication of whether all callbacks are lazy.
  * (If there are no callbacks, all of them are deemed to be lazy.)
  */
-static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy)
+static int __maybe_unused rcu_cpu_has_callbacks(bool *all_lazy)
 {
         bool al = true;
         bool hc = false;
@@ -3167,7 +3167,7 @@ static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy)
         struct rcu_state *rsp;
 
         for_each_rcu_flavor(rsp) {
-                rdp = per_cpu_ptr(rsp->rda, cpu);
+                rdp = this_cpu_ptr(rsp->rda);
                 if (!rdp->nxtlist)
                         continue;
                 hc = true;
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 495d4cce47a7..1797b76cb3ff 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1512,10 +1512,10 @@ static void rcu_prepare_kthreads(int cpu)
  * any flavor of RCU.
  */
 #ifndef CONFIG_RCU_NOCB_CPU_ALL
-int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
+int rcu_needs_cpu(unsigned long *delta_jiffies)
 {
         *delta_jiffies = ULONG_MAX;
-        return rcu_cpu_has_callbacks(cpu, NULL);
+        return rcu_cpu_has_callbacks(NULL);
 }
 #endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 
@@ -1624,15 +1624,15 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void)
  * The caller must have disabled interrupts.
  */
 #ifndef CONFIG_RCU_NOCB_CPU_ALL
-int rcu_needs_cpu(int cpu, unsigned long *dj)
+int rcu_needs_cpu(unsigned long *dj)
 {
-        struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
+        struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
 
         /* Snapshot to detect later posting of non-lazy callback. */
         rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;
 
         /* If no callbacks, RCU doesn't need the CPU. */
-        if (!rcu_cpu_has_callbacks(cpu, &rdtp->all_lazy)) {
+        if (!rcu_cpu_has_callbacks(&rdtp->all_lazy)) {
                 *dj = ULONG_MAX;
                 return 0;
         }
@@ -1679,7 +1679,7 @@ static void rcu_prepare_for_idle(int cpu)
         /* Handle nohz enablement switches conservatively. */
         tne = ACCESS_ONCE(tick_nohz_active);
         if (tne != rdtp->tick_nohz_enabled_snap) {
-                if (rcu_cpu_has_callbacks(cpu, NULL))
+                if (rcu_cpu_has_callbacks(NULL))
                         invoke_rcu_core(); /* force nohz to see update. */
                 rdtp->tick_nohz_enabled_snap = tne;
                 return;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 7b5741fc4110..1f4356037a7d 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -585,7 +585,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
                 last_jiffies = jiffies;
         } while (read_seqretry(&jiffies_lock, seq));
 
-        if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) ||
+        if (rcu_needs_cpu(&rcu_delta_jiffies) ||
             arch_needs_cpu() || irq_work_needs_cpu()) {
                 next_jiffies = last_jiffies + 1;
                 delta_jiffies = 1;