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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>
This commit is contained in:
Thomas Gleixner 2016-02-26 18:43:24 +00:00
parent 090e77c391
commit ba99746243
1 changed files with 47 additions and 22 deletions
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69
kernel/cpu.c
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@ -228,6 +228,43 @@ static int cpu_notify(unsigned long val, unsigned int cpu)
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 @@ void smpboot_thread_init(void)
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 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen)
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();