cpu/hotplug: Restructure cpu_up code
Split out into separate functions, so we can convert it to a state machine.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Rik van Riel <riel@redhat.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/20160226182340.429389195@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 41a6cb8..15a4136 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -228,6 +228,43 @@
return __cpu_notify(val, cpu, -1, NULL);
}
+/* Notifier wrappers for transitioning to state machine */
+static int notify_prepare(unsigned int cpu)
+{
+ int nr_calls = 0;
+ int ret;
+
+ ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls);
+ if (ret) {
+ nr_calls--;
+ printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n",
+ __func__, cpu);
+ __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);
+ }
+ return ret;
+}
+
+static int notify_online(unsigned int cpu)
+{
+ cpu_notify(CPU_ONLINE, cpu);
+ return 0;
+}
+
+static int bringup_cpu(unsigned int cpu)
+{
+ struct task_struct *idle = idle_thread_get(cpu);
+ int ret;
+
+ /* Arch-specific enabling code. */
+ ret = __cpu_up(cpu, idle);
+ if (ret) {
+ cpu_notify(CPU_UP_CANCELED, cpu);
+ return ret;
+ }
+ BUG_ON(!cpu_online(cpu));
+ return 0;
+}
+
#ifdef CONFIG_HOTPLUG_CPU
static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
@@ -481,7 +518,7 @@
static int _cpu_up(unsigned int cpu, int tasks_frozen)
{
struct task_struct *idle;
- int ret, nr_calls = 0;
+ int ret;
cpu_hotplug_begin();
@@ -496,33 +533,21 @@
goto out;
}
+ cpuhp_tasks_frozen = tasks_frozen;
+
ret = smpboot_create_threads(cpu);
if (ret)
goto out;
- cpuhp_tasks_frozen = tasks_frozen;
+ ret = notify_prepare(cpu);
+ if (ret)
+ goto out;
- ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls);
- if (ret) {
- nr_calls--;
- pr_warn("%s: attempt to bring up CPU %u failed\n",
- __func__, cpu);
- goto out_notify;
- }
+ ret = bringup_cpu(cpu);
+ if (ret)
+ goto out;
- /* Arch-specific enabling code. */
- ret = __cpu_up(cpu, idle);
-
- if (ret != 0)
- goto out_notify;
- BUG_ON(!cpu_online(cpu));
-
- /* Now call notifier in preparation. */
- cpu_notify(CPU_ONLINE, cpu);
-
-out_notify:
- if (ret != 0)
- __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);
+ notify_online(cpu);
out:
cpu_hotplug_done();