[PATCH v9 0/1] hibernation related patches

[PATCH v9 0/1] hibernation related patches

[Sebastian Capella]

Patchset related to hibernation resume:
  - enhancement to make the use of an existing resume file more general

  Patch is based on the 3.13 tag.  This was tested on a Beaglebone black
  with partial hibernation support, also compiled for x86_64.

[PATCH v9 1/1] PM / Hibernate: use name_to_dev_t to parse resume
  kernel/power/hibernate.c |   22 ++++++++++++----------
  1 file changed, 12 insertions(+), 10 deletions(-)

  Use name_to_dev_t to parse the /sys/power/resume file making the
  syntax more flexible.  It supports the previous use syntax
  and additionally can support other formats such as
  /dev/devicenode and UUID= formats.

  By changing /sys/debug/resume to accept the same syntax as
  the resume=device parameter, we can parse the resume=device
  in the initrd init script and use the resume device directly
  from the kernel command line.

Changes in v9:
--------------
* Dropped util changes based on feedback
* Reverted to handling newlines in resume_store

Changes in v8:
--------------
* Dropped cleanup checkpatch warnings in hibernate.c file
* Review comments for more compact checking in hibernate.c

Changes in v7:
--------------
* Switch to trim only one trailing newline if present using kstrdup_trimnl
* remove kstrimdup patch
* add kstrdup_trimnl patch
* Add clean up patch for kernel/power/hibernate.c checkpatch warnings

Changes in v6:
--------------
* Revert tricky / confusing while loop indexing

Changes in v5:
--------------
* Change kstrimdup to minimize allocated memory.  Now allocates only
  the memory needed for the string instead of using strim.

Changes in v4:
--------------
* Dropped name_to_dev_t rework in favor of adding kstrimdup
* adjusted resume_store

Changes in v3:
--------------
* Dropped documentation patch as it went in through trivial
* Added patch for name_to_dev_t to support directly parsing userspace
  buffer

Changes in v2:
--------------
* Added check for null return of kstrndup in hibernate.c


Thanks,

Sebastian

[PATCH v9] PM / Hibernate: use name_to_dev_t to parse resume

[Sebastian Capella]

Use the name_to_dev_t call to parse the device name echo'd to
to /sys/power/resume.  This imitates the method used in hibernate.c
in software_resume, and allows the resume partition to be specified
using other equivalent device formats as well.  By allowing
/sys/debug/resume to accept the same syntax as the resume=device
parameter, we can parse the resume=device in the init script and
use the resume device directly from the kernel command line.

Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
---
 kernel/power/hibernate.c |   22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 0121dab..a5f702a 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -972,16 +972,20 @@ static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 			    const char *buf, size_t n)
 {
-	unsigned int maj, min;
 	dev_t res;
-	int ret = -EINVAL;
+	int len = n;
+	char *name;
 
-	if (sscanf(buf, "%u:%u", &maj, &min) != 2)
-		goto out;
+	if (len && buf[len-1] == '\n')
+		len--;
+	name = kstrndup(buf, len, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
 
-	res = MKDEV(maj,min);
-	if (maj != MAJOR(res) || min != MINOR(res))
-		goto out;
+	res = name_to_dev_t(name);
+	kfree(name);
+	if (!res)
+		return -EINVAL;
 
 	lock_system_sleep();
 	swsusp_resume_device = res;
@@ -989,9 +993,7 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 	printk(KERN_INFO "PM: Starting manual resume from disk\n");
 	noresume = 0;
 	software_resume();
-	ret = n;
- out:
-	return ret;
+	return n;
 }
 
 power_attr(resume);
-- 
1.7.9.5

Re: [PATCH v9] PM / Hibernate: use name_to_dev_t to parse resume

[Pavel Machek]

Hi!

> Use the name_to_dev_t call to parse the device name echo'd to
> to /sys/power/resume.  This imitates the method used in hibernate.c
> in software_resume, and allows the resume partition to be specified
> using other equivalent device formats as well.  By allowing
> /sys/debug/resume to accept the same syntax as the resume=device
> parameter, we can parse the resume=device in the init script and
> use the resume device directly from the kernel command line.
> 
> Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org>
> Cc: Len Brown <len.brown@intel.com>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>

Acked-by: Pavel Machek <pavel@ucw.cz>

> @@ -972,16 +972,20 @@ static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
>  static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
>  			    const char *buf, size_t n)
>  {
> -	unsigned int maj, min;
>  	dev_t res;
> -	int ret = -EINVAL;
> +	int len = n;
> +	char *name;
>  
> -	if (sscanf(buf, "%u:%u", &maj, &min) != 2)
> -		goto out;
> +	if (len && buf[len-1] == '\n')
> +		len--;
> +	name = kstrndup(buf, len, GFP_KERNEL);
> +	if (!name)
> +		return -ENOMEM;

And yes, it seems to do right thing even if "\n" is passed to it.

> -	res = MKDEV(maj,min);
> -	if (maj != MAJOR(res) || min != MINOR(res))
> -		goto out;
> +	res = name_to_dev_t(name);
> +	kfree(name);

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[PATCH v9 0/1] hibernation related patches

[Sebastian Capella]

Patchset related to hibernation resume:
  - enhancement to make the use of an existing resume file more general

  Patch is based on the 3.13 tag.  This was tested on a Beaglebone black
  with partial hibernation support, also compiled for x86_64.

[PATCH v9 1/1] PM / Hibernate: use name_to_dev_t to parse resume
  kernel/power/hibernate.c |   22 ++++++++++++----------
  1 file changed, 12 insertions(+), 10 deletions(-)

  Use name_to_dev_t to parse the /sys/power/resume file making the
  syntax more flexible.  It supports the previous use syntax
  and additionally can support other formats such as
  /dev/devicenode and UUID= formats.

  By changing /sys/debug/resume to accept the same syntax as
  the resume=device parameter, we can parse the resume=device
  in the initrd init script and use the resume device directly
  from the kernel command line.

Changes in v9:
--------------
* Dropped util changes based on feedback
* Reverted to special newline handling in resume_store

Changes in v8:
--------------
* Dropped cleanup checkpatch warnings in hibernate.c file
* Review comments for more compact checking in hibernate.c

Changes in v7:
--------------
* Switch to trim only one trailing newline if present using kstrdup_trimnl
* remove kstrimdup patch
* add kstrdup_trimnl patch
* Add clean up patch for kernel/power/hibernate.c checkpatch warnings

Changes in v6:
--------------
* Revert tricky / confusing while loop indexing

Changes in v5:
--------------
* Change kstrimdup to minimize allocated memory.  Now allocates only
  the memory needed for the string instead of using strim.

Changes in v4:
--------------
* Dropped name_to_dev_t rework in favor of adding kstrimdup
* adjusted resume_store

Changes in v3:
--------------
* Dropped documentation patch as it went in through trivial
* Added patch for name_to_dev_t to support directly parsing userspace
  buffer

Changes in v2:
--------------
* Added check for null return of kstrndup in hibernate.c


Thanks,

Sebastian