mm: Replace deprecated CPU-hotplug functions.

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-21-bigeasy@linutronix.de

mm/swap_slots.c

@@ -70,9 +70,9 @@ void disable_swap_slots_cache_lock(void)
 	swap_slot_cache_enabled = false;
 	if (swap_slot_cache_initialized) {
 		/* serialize with cpu hotplug operations */
-		get_online_cpus();
+		cpus_read_lock();
 		__drain_swap_slots_cache(SLOTS_CACHE|SLOTS_CACHE_RET);
-		put_online_cpus();
+		cpus_read_unlock();
 	}
 }
 

mm/vmstat.c

@@ -129,9 +129,9 @@ static void sum_vm_events(unsigned long *ret)
 */
 void all_vm_events(unsigned long *ret)
 {
-	get_online_cpus();
+	cpus_read_lock();
 	sum_vm_events(ret);
-	put_online_cpus();
+	cpus_read_unlock();
 }
 EXPORT_SYMBOL_GPL(all_vm_events);
 
@@ -1948,7 +1948,7 @@ static void vmstat_shepherd(struct work_struct *w)
 {
 	int cpu;
 
-	get_online_cpus();
+	cpus_read_lock();
 	/* Check processors whose vmstat worker threads have been disabled */
 	for_each_online_cpu(cpu) {
 		struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
@@ -1958,7 +1958,7 @@ static void vmstat_shepherd(struct work_struct *w)
 
 		cond_resched();
 	}
-	put_online_cpus();
+	cpus_read_unlock();
 
 	schedule_delayed_work(&shepherd,
 		round_jiffies_relative(sysctl_stat_interval));
@@ -2037,9 +2037,9 @@ void __init init_mm_internals(void)
 	if (ret < 0)
 		pr_err("vmstat: failed to register 'online' hotplug state\n");
 
-	get_online_cpus();
+	cpus_read_lock();
 	init_cpu_node_state();
-	put_online_cpus();
+	cpus_read_unlock();
 
 	start_shepherd_timer();
 #endif