PM: hibernate: Move to crypto APIs for LZO compression

Currently for hibernation, LZO is the only compression algorithm
available and uses the existing LZO library calls. However, there
is no flexibility to switch to other algorithms which provides better
results. The main idea is that different compression algorithms have
different characteristics and hibernation may benefit when it uses
alternate algorithms.

By moving to crypto based APIs, it lays a foundation to use other
compression algorithms for hibernation. There are no functional changes
introduced by this approach.

Signed-off-by: Nikhil V <quic_nprakash@quicinc.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: vnikhilprakash

kernel/power/Kconfig

@@ -39,9 +39,9 @@ config HIBERNATION
 	bool "Hibernation (aka 'suspend to disk')"
 	depends on SWAP && ARCH_HIBERNATION_POSSIBLE
 	select HIBERNATE_CALLBACKS
-	select LZO_COMPRESS
-	select LZO_DECOMPRESS
 	select CRC32
+	select CRYPTO
+	select CRYPTO_LZO
 	help
 	  Enable the suspend to disk (STD) functionality, which is usually
 	  called "hibernation" in user interfaces.  STD checkpoints the
@@ -92,6 +92,23 @@ config HIBERNATION_SNAPSHOT_DEV
 
 	  If in doubt, say Y.
 
+choice
+	prompt "Default compressor"
+	default HIBERNATION_COMP_LZO
+	depends on HIBERNATION
+
+config HIBERNATION_COMP_LZO
+	bool "lzo"
+	depends on CRYPTO_LZO
+
+endchoice
+
+config HIBERNATION_DEF_COMP
+	string
+	default "lzo" if HIBERNATION_COMP_LZO
+	help
+	  Default compressor to be used for hibernation.
+
 config PM_STD_PARTITION
 	string "Default resume partition"
 	depends on HIBERNATION

kernel/power/hibernate.c

@@ -47,6 +47,15 @@ dev_t swsusp_resume_device;
 sector_t swsusp_resume_block;
 __visible int in_suspend __nosavedata;
 
+static const char *default_compressor = CONFIG_HIBERNATION_DEF_COMP;
+
+/*
+ * Compression/decompression algorithm to be used while saving/loading
+ * image to/from disk. This would later be used in 'kernel/power/swap.c'
+ * to allocate comp streams.
+ */
+char hib_comp_algo[CRYPTO_MAX_ALG_NAME];
+
 enum {
 	HIBERNATION_INVALID,
 	HIBERNATION_PLATFORM,
@@ -732,6 +741,17 @@ int hibernate(void)
 		return -EPERM;
 	}
 
+	/*
+	 * Query for the compression algorithm support if compression is enabled.
+	 */
+	if (!nocompress) {
+		strscpy(hib_comp_algo, default_compressor, sizeof(hib_comp_algo));
+		if (crypto_has_comp(hib_comp_algo, 0, 0) != 1) {
+			pr_err("%s compression is not available\n", hib_comp_algo);
+			return -EOPNOTSUPP;
+		}
+	}
+
 	sleep_flags = lock_system_sleep();
 	/* The snapshot device should not be opened while we're running */
 	if (!hibernate_acquire()) {
@@ -955,6 +975,19 @@ static int software_resume(void)
 	if (error)
 		goto Unlock;
 
+	/*
+	 * Check if the hibernation image is compressed. If so, query for
+	 * the algorithm support.
+	 */
+	if (!(swsusp_header_flags & SF_NOCOMPRESS_MODE)) {
+		strscpy(hib_comp_algo, default_compressor, sizeof(hib_comp_algo));
+		if (crypto_has_comp(hib_comp_algo, 0, 0) != 1) {
+			pr_err("%s compression is not available\n", hib_comp_algo);
+			error = -EOPNOTSUPP;
+			goto Unlock;
+		}
+	}
+
 	/* The snapshot device should not be opened while we're running */
 	if (!hibernate_acquire()) {
 		error = -EBUSY;

kernel/power/power.h

@@ -6,6 +6,7 @@
 #include <linux/compiler.h>
 #include <linux/cpu.h>
 #include <linux/cpuidle.h>
+#include <linux/crypto.h>
 
 struct swsusp_info {
 	struct new_utsname	uts;
@@ -54,6 +55,10 @@ asmlinkage int swsusp_save(void);
 
 /* kernel/power/hibernate.c */
 extern bool freezer_test_done;
+extern char hib_comp_algo[CRYPTO_MAX_ALG_NAME];
+
+/* kernel/power/swap.c */
+extern unsigned int swsusp_header_flags;
 
 extern int hibernation_snapshot(int platform_mode);
 extern int hibernation_restore(int platform_mode);