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>

1 files changed, 33 insertions, 0 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 4b0b7cf2e019..76b7ff619c90 100644
--- a/kernel/power/hibernate.c
+++ b/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;