rcu/kvfree: Move some functions under CONFIG_TINY_RCU

Currently when a tiny RCU is enabled, the tree.c file is not
compiled, thus duplicating function names do not conflict with
each other.

Because of moving of kvfree_rcu() functionality to the SLAB,
we have to reorder some functions and place them together under
CONFIG_TINY_RCU macro definition. Therefore, those functions name
will not conflict when a kernel is compiled for CONFIG_TINY_RCU
flavor.

Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Acked-by: Hyeonggon Yoo <[email protected]>
Tested-by: Hyeonggon Yoo <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>

Author: urezki

kernel/rcu/tree.c

@@ -3653,16 +3653,6 @@ static void kfree_rcu_monitor(struct work_struct *work)
 		schedule_delayed_monitor_work(krcp);
 }
 
-static enum hrtimer_restart
-schedule_page_work_fn(struct hrtimer *t)
-{
-	struct kfree_rcu_cpu *krcp =
-		container_of(t, struct kfree_rcu_cpu, hrtimer);
-
-	queue_delayed_work(system_highpri_wq, &krcp->page_cache_work, 0);
-	return HRTIMER_NORESTART;
-}
-
 static void fill_page_cache_func(struct work_struct *work)
 {
 	struct kvfree_rcu_bulk_data *bnode;
@@ -3698,27 +3688,6 @@ static void fill_page_cache_func(struct work_struct *work)
 	atomic_set(&krcp->backoff_page_cache_fill, 0);
 }
 
-static void
-run_page_cache_worker(struct kfree_rcu_cpu *krcp)
-{
-	// If cache disabled, bail out.
-	if (!rcu_min_cached_objs)
-		return;
-
-	if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING &&
-			!atomic_xchg(&krcp->work_in_progress, 1)) {
-		if (atomic_read(&krcp->backoff_page_cache_fill)) {
-			queue_delayed_work(system_unbound_wq,
-				&krcp->page_cache_work,
-					msecs_to_jiffies(rcu_delay_page_cache_fill_msec));
-		} else {
-			hrtimer_init(&krcp->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-			krcp->hrtimer.function = schedule_page_work_fn;
-			hrtimer_start(&krcp->hrtimer, 0, HRTIMER_MODE_REL);
-		}
-	}
-}
-
 // Record ptr in a page managed by krcp, with the pre-krc_this_cpu_lock()
 // state specified by flags.  If can_alloc is true, the caller must
 // be schedulable and not be holding any locks or mutexes that might be
@@ -3779,6 +3748,51 @@ add_ptr_to_bulk_krc_lock(struct kfree_rcu_cpu **krcp,
 	return true;
 }
 
+#if !defined(CONFIG_TINY_RCU)
+
+static enum hrtimer_restart
+schedule_page_work_fn(struct hrtimer *t)
+{
+	struct kfree_rcu_cpu *krcp =
+		container_of(t, struct kfree_rcu_cpu, hrtimer);
+
+	queue_delayed_work(system_highpri_wq, &krcp->page_cache_work, 0);
+	return HRTIMER_NORESTART;
+}
+
+static void
+run_page_cache_worker(struct kfree_rcu_cpu *krcp)
+{
+	// If cache disabled, bail out.
+	if (!rcu_min_cached_objs)
+		return;
+
+	if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING &&
+			!atomic_xchg(&krcp->work_in_progress, 1)) {
+		if (atomic_read(&krcp->backoff_page_cache_fill)) {
+			queue_delayed_work(system_unbound_wq,
+				&krcp->page_cache_work,
+					msecs_to_jiffies(rcu_delay_page_cache_fill_msec));
+		} else {
+			hrtimer_init(&krcp->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+			krcp->hrtimer.function = schedule_page_work_fn;
+			hrtimer_start(&krcp->hrtimer, 0, HRTIMER_MODE_REL);
+		}
+	}
+}
+
+void __init kfree_rcu_scheduler_running(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
+
+		if (need_offload_krc(krcp))
+			schedule_delayed_monitor_work(krcp);
+	}
+}
+
 /*
  * Queue a request for lazy invocation of the appropriate free routine
  * after a grace period.  Please note that three paths are maintained,
@@ -3944,6 +3958,8 @@ void kvfree_rcu_barrier(void)
 }
 EXPORT_SYMBOL_GPL(kvfree_rcu_barrier);
 
+#endif /* #if !defined(CONFIG_TINY_RCU) */
+
 static unsigned long
 kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 {
@@ -3985,18 +4001,6 @@ kfree_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 	return freed == 0 ? SHRINK_STOP : freed;
 }
 
-void __init kfree_rcu_scheduler_running(void)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu) {
-		struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
-
-		if (need_offload_krc(krcp))
-			schedule_delayed_monitor_work(krcp);
-	}
-}
-
 /*
  * During early boot, any blocking grace-period wait automatically
  * implies a grace period.