[PATCH 7/10] msr: fix cpu hotplug error handling

Akinobu Mita
2007-07-16T14:08:25Z

Make msr_device_create() CPU_UP_PREPARE event handler
instead of CPU_ONLINE handler.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

---
arch/i386/kernel/msr.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)

Index: 2.6-mm/arch/i386/kernel/msr.c
===================================================================
--- 2.6-mm.orig/arch/i386/kernel/msr.c
+++ 2.6-mm/arch/i386/kernel/msr.c
@@ -135,33 +135,39 @@ static const struct file_operations msr_
.open = msr_open,
};

-static int msr_device_create(int i)
+static int msr_device_create(int cpu)
{
- int err = 0;
struct device *dev;

- dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, i), "msr%d",i);
- if (IS_ERR(dev))
- err = PTR_ERR(dev);
- return err;
+ dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu),
+ "msr%d", cpu);
+ return IS_ERR(dev) ? PTR_ERR(dev) : 0;
+}
+
+static void msr_device_destroy(int cpu)
+{
+ device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
}

static int msr_class_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
+ int err = 0;

switch (action) {
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- msr_device_create(cpu);
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ err = msr_device_create(cpu);
break;
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
- device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+ msr_device_destroy(cpu);
break;
}
- return NOTIFY_OK;
+ return err ? NOTIFY_BAD : NOTIFY_OK;
}

static struct notifier_block __cpuinitdata msr_class_cpu_notifier =
@@ -198,7 +204,7 @@ static int __init msr_init(void)
out_class:
i = 0;
for_each_online_cpu(i)
- device_destroy(msr_class, MKDEV(MSR_MAJOR, i));
+ msr_device_destroy(i);
class_destroy(msr_class);
out_chrdev:
unregister_chrdev(MSR_MAJOR, "cpu/msr");
@@ -210,7 +216,7 @@ static void __exit msr_exit(void)
{
int cpu = 0;
for_each_online_cpu(cpu)
- device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+ msr_device_destroy(cpu);
class_destroy(msr_class);
unregister_chrdev(MSR_MAJOR, "cpu/msr");
unregister_hotcpu_notifier(&msr_class_cpu_notifier);