PM / Hibernate: Compress hibernation image with LZO

Compress hibernation image with LZO in order to save on I/O and
therefore time to hibernate/thaw.

[rjw: Added hibernate=nocompress command line option instead of just
 nocompress which would be confusing, fixed a couple of compiler
 warnings, fixed kerneldoc comments, minor cleanups.]

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Documentation/kernel-parameters.txt

@@ -2165,6 +2165,11 @@ and is between 256 and 4096 characters. It is defined in the file
 			in <PAGE_SIZE> units (needed only for swap files).
 			See  Documentation/power/swsusp-and-swap-files.txt
 
+	hibernate=	[HIBERNATION]
+		noresume	Don't check if there's a hibernation image
+				present during boot.
+		nocompress	Don't compress/decompress hibernation images.
+
 	retain_initrd	[RAM] Keep initrd memory after extraction
 
 	rhash_entries=	[KNL,NET]

Documentation/power/swsusp.txt

@@ -66,7 +66,8 @@ swsusp saves the state of the machine into active swaps and then reboots or
 powerdowns.  You must explicitly specify the swap partition to resume from with
 ``resume='' kernel option. If signature is found it loads and restores saved
 state. If the option ``noresume'' is specified as a boot parameter, it skips
-the resuming.
+the resuming.  If the option ``hibernate=nocompress'' is specified as a boot
+parameter, it saves hibernation image without compression.
 
 In the meantime while the system is suspended you should not add/remove any
 of the hardware, write to the filesystems, etc.

kernel/power/Kconfig

@@ -137,6 +137,8 @@ config SUSPEND_FREEZER
 config HIBERNATION
 	bool "Hibernation (aka 'suspend to disk')"
 	depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
 	select SUSPEND_NVS if HAS_IOMEM
 	---help---
 	  Enable the suspend to disk (STD) functionality, which is usually

kernel/power/hibernate.c

@@ -29,6 +29,7 @@
 #include "power.h"
 
 
+static int nocompress = 0;
 static int noresume = 0;
 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
 dev_t swsusp_resume_device;
@@ -638,6 +639,8 @@ int hibernate(void)
 
 		if (hibernation_mode == HIBERNATION_PLATFORM)
 			flags |= SF_PLATFORM_MODE;
+		if (nocompress)
+			flags |= SF_NOCOMPRESS_MODE;
 		pr_debug("PM: writing image.\n");
 		error = swsusp_write(flags);
 		swsusp_free();
@@ -1004,6 +1007,15 @@ static int __init resume_offset_setup(char *str)
 	return 1;
 }
 
+static int __init hibernate_setup(char *str)
+{
+	if (!strncmp(str, "noresume", 8))
+		noresume = 1;
+	else if (!strncmp(str, "nocompress", 10))
+		nocompress = 1;
+	return 1;
+}
+
 static int __init noresume_setup(char *str)
 {
 	noresume = 1;
@@ -1013,3 +1025,4 @@ static int __init noresume_setup(char *str)
 __setup("noresume", noresume_setup);
 __setup("resume_offset=", resume_offset_setup);
 __setup("resume=", resume_setup);
+__setup("hibernate=", hibernate_setup);

kernel/power/power.h

@@ -134,6 +134,7 @@ extern int swsusp_swap_in_use(void);
  * the image header.
  */
 #define SF_PLATFORM_MODE	1
+#define SF_NOCOMPRESS_MODE	2
 
 /* kernel/power/hibernate.c */
 extern int swsusp_check(void);