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SubjectRe: [patch 05/40] cpu: Restructure cpu_down code
On Thu, Jan 31, 2013 at 12:11:15PM -0000, Thomas Gleixner wrote:
> Split out into separate functions, so we can convert it to a state machine.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Refreshed:

From linux-kernel-owner@vger.kernel.org Thu Jan 31 13:11:32 2013
Message-Id: <20130131120741.823640323@linutronix.de>
User-Agent: quilt/0.48-1
Date: Thu, 31 Jan 2013 12:11:15 -0000
From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
Rusty Russell <rusty@rustcorp.com.au>, Paul McKenney
<paulmck@linux.vnet.ibm.com>, "Srivatsa S. Bhat"
<srivatsa.bhat@linux.vnet.ibm.com>, Arjan van de Veen <arjan@infradead.org>,
Paul Turner <pjt@google.com>, Richard Weinberger <rw@linutronix.de>, Magnus
Damm <magnus.damm@gmail.com>
Subject: [patch 05/40] cpu: Restructure cpu_down code
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset=utf-8
Status: RO

Split out into separate functions, so we can convert it to a state machine.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/cpu.c | 69 ++++++++++++++++++++++++++++++++++++++++-------------------
1 file changed, 47 insertions(+), 22 deletions(-)

Index: linux/kernel/cpu.c
===================================================================
--- linux.orig/kernel/cpu.c 2014-10-09 18:54:47.251793646 +0200
+++ linux/kernel/cpu.c 2014-10-09 19:00:46.743791277 +0200
@@ -214,6 +214,43 @@ static int cpu_notify(unsigned long val,
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)
@@ -421,7 +458,7 @@ EXPORT_SYMBOL(cpu_down);
static int _cpu_up(unsigned int cpu, int tasks_frozen)
{
struct task_struct *idle;
- int ret, nr_calls = 0;
+ int ret;

cpu_hotplug_begin();

@@ -436,35 +473,24 @@ static int _cpu_up(unsigned int cpu, int
goto out;
}

+ cpuhp_tasks_frozen = tasks_frozen;
+
ret = smpboot_create_threads(cpu);
if (ret)
goto out;

- cpuhp_tasks_frozen = tasks_frozen;
-
- 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 = notify_prepare(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));
+ ret = bringup_cpu(cpu);
+ if (ret)
+ goto out;

/* Wake the per cpu threads */
smpboot_unpark_threads(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();

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
--


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