x86/microcode: 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/20210803141621.780504-9-bigeasy@linutronix.de

arch/x86/kernel/cpu/microcode/core.c

@@ -55,7 +55,7 @@ LIST_HEAD(microcode_cache);
  * All non cpu-hotplug-callback call sites use:
  *
  * - microcode_mutex to synchronize with each other;
- * - get/put_online_cpus() to synchronize with
+ * - cpus_read_lock/unlock() to synchronize with
  *   the cpu-hotplug-callback call sites.
  *
  * We guarantee that only a single cpu is being
@@ -431,7 +431,7 @@ static ssize_t microcode_write(struct file *file, const char __user *buf,
 		return ret;
 	}
 
-	get_online_cpus();
+	cpus_read_lock();
 	mutex_lock(&microcode_mutex);
 
 	if (do_microcode_update(buf, len) == 0)
@@ -441,7 +441,7 @@ static ssize_t microcode_write(struct file *file, const char __user *buf,
 		perf_check_microcode();
 
 	mutex_unlock(&microcode_mutex);
-	put_online_cpus();
+	cpus_read_unlock();
 
 	return ret;
 }
@@ -629,7 +629,7 @@ static ssize_t reload_store(struct device *dev,
 	if (val != 1)
 		return size;
 
-	get_online_cpus();
+	cpus_read_lock();
 
 	ret = check_online_cpus();
 	if (ret)
@@ -644,7 +644,7 @@ static ssize_t reload_store(struct device *dev,
 	mutex_unlock(&microcode_mutex);
 
 put:
-	put_online_cpus();
+	cpus_read_unlock();
 
 	if (ret == 0)
 		ret = size;
@@ -853,14 +853,14 @@ static int __init microcode_init(void)
 	if (IS_ERR(microcode_pdev))
 		return PTR_ERR(microcode_pdev);
 
-	get_online_cpus();
+	cpus_read_lock();
 	mutex_lock(&microcode_mutex);
 
 	error = subsys_interface_register(&mc_cpu_interface);
 	if (!error)
 		perf_check_microcode();
 	mutex_unlock(&microcode_mutex);
-	put_online_cpus();
+	cpus_read_unlock();
 
 	if (error)
 		goto out_pdev;
@@ -892,13 +892,13 @@ static int __init microcode_init(void)
 			   &cpu_root_microcode_group);
 
  out_driver:
-	get_online_cpus();
+	cpus_read_lock();
 	mutex_lock(&microcode_mutex);
 
 	subsys_interface_unregister(&mc_cpu_interface);
 
 	mutex_unlock(&microcode_mutex);
-	put_online_cpus();
+	cpus_read_unlock();
 
  out_pdev:
 	platform_device_unregister(microcode_pdev);