Re: [PATCH 7/8] kernel/power/main.c: Not suspend/resume if CPU0 is offlined

["Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>]

Hi,

On 10/05/2011 10:09 PM, Fenghua Yu wrote:
> 
> @@ -178,6 +179,14 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
>  	int len;
>  	int error = -EINVAL;
> 
> +#ifdef CONFIG_HOTPLUG_CPU
> +	if (bsp_hotpluggable && cpumask_first(cpu_online_mask) != 0) {
> +		printk(KERN_WARNING "Because CPU0 is offlined, system can't suspend/resume.\n");
> +
> +		return -ENODEV;
> +	}
> +#endif

There is a possible race condition here. What if CPU0 gets offlined
AFTER this point(due to a CPU hotplug operation)?
We will probably have to prevent CPU0 from being taken offline from
this point onwards, and remove that restriction later on.

> +
>  	p = memchr(buf, '\n', n);
>  	len = p ? p - buf : n;
> 


-- 
Regards,
Srivatsa S. Bhat  <srivatsa.bhat@linux.vnet.ibm.com>
Linux Technology Center,
IBM India Systems and Technology Lab