kernel/printk: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161103145021.28528-3-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 69b74fa0da60c2010efb2b9d185e617a45f4dffc..4174083280d739021da9372c46bbb56682c2f2e1 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -31,6 +31,7 @@ enum cpuhp_state {
        CPUHP_S390_PFAULT_DEAD,
        CPUHP_BLK_MQ_DEAD,
        CPUHP_FS_BUFF_DEAD,
+       CPUHP_PRINTK_DEAD,
        CPUHP_WORKQUEUE_PREP,
        CPUHP_POWER_NUMA_PREPARE,
        CPUHP_HRTIMERS_PREPARE,

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index de08fc90baafaf86d3053831d2cc0acd5cb9828e..4487ffcd42d57ae6b47e10a08e140e54f18f1079 100644 (file)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2185,27 +2185,18 @@ void resume_console(void)
 
 /**
  * console_cpu_notify - print deferred console messages after CPU hotplug
- * @self: notifier struct
- * @action: CPU hotplug event
- * @hcpu: unused
+ * @cpu: unused
  *
  * If printk() is called from a CPU that is not online yet, the messages
  * will be spooled but will not show up on the console.  This function is
  * called when a new CPU comes online (or fails to come up), and ensures
  * that any such output gets printed.
  */
-static int console_cpu_notify(struct notifier_block *self,
-       unsigned long action, void *hcpu)
-{
-       switch (action) {
-       case CPU_ONLINE:
-       case CPU_DEAD:
-       case CPU_DOWN_FAILED:
-       case CPU_UP_CANCELED:
-               console_lock();
-               console_unlock();
-       }
-       return NOTIFY_OK;
+static int console_cpu_notify(unsigned int cpu)
+{
+       console_lock();
+       console_unlock();
+       return 0;
 }
 
 /**
@@ -2843,6 +2834,7 @@ EXPORT_SYMBOL(unregister_console);
 static int __init printk_late_init(void)
 {
        struct console *con;
+       int ret;
 
        for_each_console(con) {
                if (!keep_bootcon && con->flags & CON_BOOT) {
@@ -2857,7 +2849,12 @@ static int __init printk_late_init(void)
                                unregister_console(con);
                }
        }
-       hotcpu_notifier(console_cpu_notify, 0);
+       ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL,
+                                       console_cpu_notify);
+       WARN_ON(ret < 0);
+       ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "printk:online",
+                                       console_cpu_notify, NULL);
+       WARN_ON(ret < 0);
        return 0;
 }
 late_initcall(printk_late_init);