linux-kernel - Re: [PATCH v2 1/2] hibernate: create "nohibernate" boot parameter

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Date:	Fri, 13 Jun 2014 12:56:10 +0200
From:	Pavel Machek <pavel@....cz>
To:	Kees Cook <keescook@...omium.org>
Cc:	linux-kernel@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"H. Peter Anvin" <hpa@...or.com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
	Len Brown <len.brown@...el.com>,
	Wei Yongjun <yongjun_wei@...ndmicro.com.cn>,
	linux-doc@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 1/2] hibernate: create "nohibernate" boot parameter

On Thu 2014-06-12 14:00:32, Kees Cook wrote:
> To support using kernel features that are not compatible with hibernation,
> this creates the "nohibernate" kernel boot parameter to disable both
> hibernation and resume. This allows hibernation support to be a boot-time
> choice instead of only a compile-time choice.
> 
> Signed-off-by: Kees Cook <keescook@...omium.org>


> @@ -639,6 +645,11 @@ int hibernate(void)
>  {
>  	int error;
>  
> +	if (!hibernation_available()) {
> +		pr_debug("PM: Hibernation not available.\n");
> +		return -EINVAL;
> +	}
> +
>  	lock_system_sleep();
>  	/* The snapshot device should not be opened while we're running */
>  	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
> @@ -931,6 +945,9 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
>  	char *p;
>  	int mode = HIBERNATION_INVALID;
>  
> +	if (!hibernation_available())
> +		return -EINVAL;
> +
>  	p = memchr(buf, '\n', n);
>  	len = p ? p - buf : n;
>  
> diff --git a/kernel/power/user.c b/kernel/power/user.c
> index 98d357584cd6..000b94419182 100644
> --- a/kernel/power/user.c
> +++ b/kernel/power/user.c
> @@ -49,6 +49,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
>  	struct snapshot_data *data;
>  	int error;
>  
> +	if (!hibernation_available())
> +		return -EINVAL;
> +
>  	lock_system_sleep();
>  
>  	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {

Is EINVAL right error code for "root disabled that option"?

Otherwise it looks ok, you can add my ack with that fixed.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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