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--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -10,6 +10,23 @@ menu "Library routines"
config RAID6_PQ
tristate
+config RAID6_PQ_DEFAULT_ALG_BOOL
+ bool "Default RAID6 PQ algorithm"
+ default n
+ depends on RAID6_PQ
+ help
+ Allow for specifying a default algorithm via the kernel
+ parameter "raid6_pq_default_alg", which forces the performance
+ tests to be skipped. This can save between 500ms to 2s
+ during boot.
+
+config RAID6_PQ_DEFAULT_ALG
+ string "Default RAID6 PQ algorithm name"
+ default ""
+ depends on RAID6_PQ_DEFAULT_ALG_BOOL
+ help
+ The default algorithm name to be used by default.
+
config BITREVERSE
tristate
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index d3b16f43c39f..480cbfbe293f 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -30,6 +30,12 @@ EXPORT_SYMBOL(raid6_empty_zero_page);
#endif
#endif
+#ifdef CONFIG_RAID6_PQ_DEFAULT_ALG_BOOL
+static char raid6_pq_default_alg[32] = CONFIG_RAID6_PQ_DEFAULT_ALG;
+module_param_string(raid6_pq_default_alg, raid6_pq_default_alg, sizeof(raid6_pq_default_alg), 0444);
+MODULE_PARM_DESC(raid6_pq_default_alg, "Default gen/xor() algorithm");
+#endif
+
struct raid6_calls raid6_call;
EXPORT_SYMBOL_GPL(raid6_call);
@@ -157,6 +163,26 @@ static inline const struct raid6_calls *raid6_choose_gen(
const struct raid6_calls *const *algo;
const struct raid6_calls *best;
+#ifdef CONFIG_RAID6_PQ_DEFAULT_ALG_BOOL
+ if (strlen(raid6_pq_default_alg)) {
+ for (algo = raid6_algos; *algo; algo++) {
+ if (!strncmp(raid6_pq_default_alg, (*algo)->name, sizeof(raid6_pq_default_alg))) {
+ if ((*algo)->valid && !(*algo)->valid()) {
+ pr_info("raid6: default alg \"%s\" is invalid.\n",
+ raid6_pq_default_alg);
+ continue;
+ }
+ pr_info("raid6: using default algorithm %s gen() without performace tests.\n",
+ (*algo)->name);
+ raid6_call = **algo;
+ return *algo;
+ }
+ }
+ pr_info("raid6: default alg \"%s\" not found. Choosing the best alg as fallback...\n",
+ raid6_pq_default_alg);
+ }
+#endif
+
for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
if (!best || (*algo)->prefer >= best->prefer) {
/* 2 ^ (RAID6_TIME_JIFFIES_LG2 - 0.5) */
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