[PATCH v3 1/2] power/hibernate: Make passing hibernate offsets more friendly

[PATCH v3 1/2] power/hibernate: Make passing hibernate offsets more friendly

[Mario Limonciello]

Currently the only way to specify a hibernate offset for a
swap file is on the kernel command line.

Add a new /sys/power/resume_offset that lets userspace
specify the offset and disk to use when initiating a hibernate
cycle.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
---
Changes from v2:
 * Cast the output for sector_t when printing
 * Fix a compilation problem with i386 due to different size of sector_t

 Documentation/ABI/testing/sysfs-power | 14 ++++++++++++++
 Documentation/power/swsusp.txt        | 10 +++++++++-
 kernel/power/hibernate.c              | 24 ++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index 1e0d1da..2f813d6 100644
--- a/Documentation/ABI/testing/sysfs-power
+++ b/Documentation/ABI/testing/sysfs-power
@@ -287,3 +287,17 @@ Description:
 		Writing a "1" to this file enables the debug messages and
 		writing a "0" (default) to it disables them.  Reads from
 		this file return the current value.
+
+What:		/sys/power/resume_offset
+Date:		April 2018
+Contact:	Mario Limonciello <mario.limonciello@dell.com>
+Description:
+		This file is used for telling the kernel an offset into a disk
+		to use when hibernating the system such as with a swap file.
+
+		Reads from this file will display the current offset
+		the kernel will be using on the next hibernation
+		attempt.
+
+		Using this sysfs file will override any values that were
+		set using the kernel command line for disk offset.
\ No newline at end of file
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index 9f2f942..cc87adf 100644
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -24,8 +24,16 @@ Some warnings, first.
  * see the FAQ below for details.  (This is not true for more traditional
  * power states like "standby", which normally don't turn USB off.)
 
+Swap partition:
 You need to append resume=/dev/your_swap_partition to kernel command
-line. Then you suspend by
+line or specify it using /sys/power/resume.
+
+Swap file:
+If using a swapfile you can also specify a resume offset using
+resume_offset=<number> on the kernel command line or specify it
+in /sys/power/resume_offset.
+
+After preparing then you suspend by
 
 echo shutdown > /sys/power/disk; echo disk > /sys/power/state
 
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index a5c36e9..d58fad3d 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -1061,6 +1061,29 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 
 power_attr(resume);
 
+static ssize_t resume_offset_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
+}
+
+static ssize_t resume_offset_store(struct kobject *kobj,
+				   struct kobj_attribute *attr, const char *buf,
+				   size_t n)
+{
+	unsigned long long offset;
+	int rc;
+
+	rc = kstrtoull(buf, 0, &offset);
+	if (rc)
+		return rc;
+	swsusp_resume_block = offset;
+
+	return n;
+}
+
+power_attr(resume_offset);
+
 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
 			       char *buf)
 {
@@ -1106,6 +1129,7 @@ power_attr(reserved_size);
 
 static struct attribute * g[] = {
 	&disk_attr.attr,
+	&resume_offset_attr.attr,
 	&resume_attr.attr,
 	&image_size_attr.attr,
 	&reserved_size_attr.attr,
-- 
2.7.4

[PATCH v3 2/2] power/hibernate: Change message when writing to /sys/power/resume

[Mario Limonciello]

This file is used both for setting the wakeup device without kernel
command line as well as for actually waking the system (when appropriate
swap header is in place).

To avoid confusion on incorrect logs in system log downgrade the
message to debug and make it clearer.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
---
 kernel/power/hibernate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index d58fad3d..1028ecb 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -1053,7 +1053,7 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 	lock_system_sleep();
 	swsusp_resume_device = res;
 	unlock_system_sleep();
-	pr_info("Starting manual resume from disk\n");
+	pm_pr_dbg("Configured resume from disk to %u\n", swsusp_resume_device);
 	noresume = 0;
 	software_resume();
 	return n;
-- 
2.7.4

Re: [PATCH v3 2/2] power/hibernate: Change message when writing to /sys/power/resume

[Rafael J. Wysocki]

On Wednesday, March 28, 2018 7:01:10 PM CEST Mario Limonciello wrote:
> This file is used both for setting the wakeup device without kernel
> command line as well as for actually waking the system (when appropriate
> swap header is in place).
> 
> To avoid confusion on incorrect logs in system log downgrade the
> message to debug and make it clearer.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> ---
>  kernel/power/hibernate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index d58fad3d..1028ecb 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -1053,7 +1053,7 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
>  	lock_system_sleep();
>  	swsusp_resume_device = res;
>  	unlock_system_sleep();
> -	pr_info("Starting manual resume from disk\n");
> +	pm_pr_dbg("Configured resume from disk to %u\n", swsusp_resume_device);
>  	noresume = 0;
>  	software_resume();
>  	return n;
> 

Both [1-2/2] applied, thanks!