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Subject[RFC PATCH 03/11] cpu: Add cpu hotplug handlers
Date
Added cpu hotplug handlers.  cpu_add_execute() onlines requested
cpus for hot-add and online operations, and cpu_del_execute()
offlines them for hot-delete and offline operations. They are
also used for rollback as well.

cpu_del_validate() fails a request if cpu0 is requested to delete.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
---
drivers/base/cpu.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 95 insertions(+)

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 6345294..3870231 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -13,6 +13,8 @@
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/percpu.h>
+#include <linux/list.h>
+#include <linux/hotplug.h>

#include "base.h"

@@ -324,10 +326,103 @@ static void __init cpu_dev_register_generic(void)
#endif
}

+#ifdef CONFIG_HOTPLUG_CPU
+static int cpu_del_execute(struct hp_request *req, int rollback);
+
+static int cpu_add_execute(struct hp_request *req, int rollback)
+{
+ struct hp_device *hp_dev;
+ u32 cpu;
+ int ret;
+
+ if (rollback)
+ return cpu_del_execute(req, 0);
+
+ list_for_each_entry(hp_dev, &req->dev_list, list) {
+ if (hp_dev->class != HP_CLS_CPU)
+ continue;
+
+ cpu = hp_dev->data.cpu.cpu_id;
+
+ if (cpu_online(cpu))
+ continue;
+
+ ret = cpu_up(cpu);
+ /* REVISIT: need a way to set a cpu dev for hot-plug op */
+ if (!ret && hp_is_online_op(req->operation))
+ kobject_uevent(&hp_dev->device->kobj, KOBJ_ONLINE);
+ }
+
+ return 0;
+}
+
+static int cpu_del_validate(struct hp_request *req, int rollback)
+{
+ struct hp_device *hp_dev;
+
+ if (rollback)
+ return 0;
+
+ list_for_each_entry(hp_dev, &req->dev_list, list) {
+ if (hp_dev->class != HP_CLS_CPU)
+ continue;
+
+ /*
+ * cpu 0 cannot be offlined. This check can be removed when
+ * cpu 0 offline is supported.
+ */
+ if (hp_dev->data.cpu.cpu_id == 0)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int cpu_del_execute(struct hp_request *req, int rollback)
+{
+ struct hp_device *hp_dev;
+ u32 cpu;
+ int ret;
+
+ if (rollback)
+ return cpu_add_execute(req, 0);
+
+ list_for_each_entry(hp_dev, &req->dev_list, list) {
+ if (hp_dev->class != HP_CLS_CPU)
+ continue;
+
+ cpu = hp_dev->data.cpu.cpu_id;
+
+ if (!cpu_online(cpu))
+ continue;
+
+ ret = cpu_down(cpu);
+ /* REVISIT: need a way to set a cpu dev for hot-plug op */
+ if (!ret && hp_is_online_op(req->operation))
+ kobject_uevent(&hp_dev->device->kobj, KOBJ_OFFLINE);
+ }
+
+ return 0;
+}
+
+static void __init cpu_hp_init(void)
+{
+ hp_register_handler(HP_ADD_EXECUTE, cpu_add_execute,
+ HP_CPU_ADD_EXECUTE_ORDER);
+ hp_register_handler(HP_DEL_VALIDATE, cpu_del_validate,
+ HP_CPU_DEL_VALIDATE_ORDER);
+ hp_register_handler(HP_DEL_EXECUTE, cpu_del_execute,
+ HP_CPU_DEL_EXECUTE_ORDER);
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
void __init cpu_dev_init(void)
{
if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
panic("Failed to register CPU subsystem");

cpu_dev_register_generic();
+#ifdef CONFIG_HOTPLUG_CPU
+ cpu_hp_init();
+#endif
}
--
1.7.11.7


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