From 3a9b8702ecf4b0e11a42680766fa7a0e6b8f0fe8 Mon Sep 17 00:00:00 2001
From: jc_gargma <jc_gargma@iserlohn-fortress.net>
Date: Mon, 18 Feb 2019 07:58:07 -0800
Subject: Updated to 4.20.10.a - Added raid6 preselected algorithm patch.
 Anyone that uses raid6 and has avx2 should change it to avx2x4.

---
 raid6-default-algo.patch | 70 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 raid6-default-algo.patch

(limited to 'raid6-default-algo.patch')

diff --git a/raid6-default-algo.patch b/raid6-default-algo.patch
new file mode 100644
index 0000000..98bfd54
--- /dev/null
+++ b/raid6-default-algo.patch
@@ -0,0 +1,70 @@
+--- 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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