[PATCH PREVIEW RFC 2/6] raid6: Add bootcache

[acampanella-thegoodpenguin <acampanella@thegoodpenguin.co.uk>]

Check for previously cached results before benchmark

Signed-off-by: Andrea Campanella <acampanella@thegoodpenguin.co.uk>
---
 lib/raid6/algos.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index 799e0e5eac26db3d10c07e79f46537af4ec6f182..fc69d94afdb4fc153626a3e21c506eda57540618 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/gfp.h>
 #endif
+#include <linux/bootcache.h>
 
 struct raid6_calls raid6_call;
 EXPORT_SYMBOL_GPL(raid6_call);
@@ -159,6 +160,24 @@ static inline const struct raid6_calls *raid6_choose_gen(
 	int start = (disks>>1)-1, stop = disks-3;	/* work on the second half of the disks */
 	const struct raid6_calls *const *algo;
 	const struct raid6_calls *best;
+	char cached_algo_name[32];
+
+	/* Try to get cached algorithm by name */
+	if (bootcache_get_string("raid6_best_algo", cached_algo_name,
+		sizeof(cached_algo_name)) == 0) {
+		/* Find algorithm by name */
+		for (algo = raid6_algos; *algo; algo++) {
+			if (strcmp((*algo)->name, cached_algo_name) == 0) {
+				if (!(*algo)->valid || (*algo)->valid()) {
+					raid6_call = *algo;
+					pr_info("raid6: using algorithm %s (from cache)\n",
+						(*algo)->name);
+					return best;
+				}
+				break;
+			}
+		}
+	}
 
 	for (bestgenperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
 		if (!best || (*algo)->priority >= best->priority) {
@@ -198,6 +217,8 @@ static inline const struct raid6_calls *raid6_choose_gen(
 		goto out;
 	}
 
+	bootcache_set_string("raid6_best_algo", best->name);
+
 	raid6_call = *best;
 
 	if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {

-- 
2.48.1