Initial import

1 files changed, 250 insertions, 0 deletions

diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
new file mode 100644
index 000000000..975c6e043
--- /dev/null
+++ b/lib/raid6/algos.c
@@ -0,0 +1,250 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright 2002 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * raid6/algos.c
+ *
+ * Algorithm list and algorithm selection for RAID-6
+ */
+
+#include <linux/raid/pq.h>
+#ifndef __KERNEL__
+#include <sys/mman.h>
+#include <stdio.h>
+#else
+#include <linux/module.h>
+#include <linux/gfp.h>
+#if !RAID6_USE_EMPTY_ZERO_PAGE
+/* In .bss so it's zeroed */
+const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
+EXPORT_SYMBOL(raid6_empty_zero_page);
+#endif
+#endif
+
+struct raid6_calls raid6_call;
+EXPORT_SYMBOL_GPL(raid6_call);
+
+const struct raid6_calls * const raid6_algos[] = {
+#if defined(__ia64__)
+	&raid6_intx16,
+	&raid6_intx32,
+#endif
+#if defined(__i386__) && !defined(__arch_um__)
+	&raid6_mmxx1,
+	&raid6_mmxx2,
+	&raid6_sse1x1,
+	&raid6_sse1x2,
+	&raid6_sse2x1,
+	&raid6_sse2x2,
+#ifdef CONFIG_AS_AVX2
+	&raid6_avx2x1,
+	&raid6_avx2x2,
+#endif
+#endif
+#if defined(__x86_64__) && !defined(__arch_um__)
+	&raid6_sse2x1,
+	&raid6_sse2x2,
+	&raid6_sse2x4,
+#ifdef CONFIG_AS_AVX2
+	&raid6_avx2x1,
+	&raid6_avx2x2,
+	&raid6_avx2x4,
+#endif
+#endif
+#ifdef CONFIG_ALTIVEC
+	&raid6_altivec1,
+	&raid6_altivec2,
+	&raid6_altivec4,
+	&raid6_altivec8,
+#endif
+#if defined(CONFIG_TILEGX)
+	&raid6_tilegx8,
+#endif
+	&raid6_intx1,
+	&raid6_intx2,
+	&raid6_intx4,
+	&raid6_intx8,
+#ifdef CONFIG_KERNEL_MODE_NEON
+	&raid6_neonx1,
+	&raid6_neonx2,
+	&raid6_neonx4,
+	&raid6_neonx8,
+#endif
+	NULL
+};
+
+void (*raid6_2data_recov)(int, size_t, int, int, void **);
+EXPORT_SYMBOL_GPL(raid6_2data_recov);
+
+void (*raid6_datap_recov)(int, size_t, int, void **);
+EXPORT_SYMBOL_GPL(raid6_datap_recov);
+
+const struct raid6_recov_calls *const raid6_recov_algos[] = {
+#ifdef CONFIG_AS_AVX2
+	&raid6_recov_avx2,
+#endif
+#ifdef CONFIG_AS_SSSE3
+	&raid6_recov_ssse3,
+#endif
+	&raid6_recov_intx1,
+	NULL
+};
+
+#ifdef __KERNEL__
+#define RAID6_TIME_JIFFIES_LG2	4
+#else
+/* Need more time to be stable in userspace */
+#define RAID6_TIME_JIFFIES_LG2	9
+#define time_before(x, y) ((x) < (y))
+#endif
+
+static inline const struct raid6_recov_calls *raid6_choose_recov(void)
+{
+	const struct raid6_recov_calls *const *algo;
+	const struct raid6_recov_calls *best;
+
+	for (best = NULL, algo = raid6_recov_algos; *algo; algo++)
+		if (!best || (*algo)->priority > best->priority)
+			if (!(*algo)->valid || (*algo)->valid())
+				best = *algo;
+
+	if (best) {
+		raid6_2data_recov = best->data2;
+		raid6_datap_recov = best->datap;
+
+		pr_info("raid6: using %s recovery algorithm\n", best->name);
+	} else
+		pr_err("raid6: Yikes! No recovery algorithm found!\n");
+
+	return best;
+}
+
+static inline const struct raid6_calls *raid6_choose_gen(
+	void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks)
+{
+	unsigned long perf, bestgenperf, bestxorperf, j0, j1;
+	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;
+
+	for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
+		if (!best || (*algo)->prefer >= best->prefer) {
+			if ((*algo)->valid && !(*algo)->valid())
+				continue;
+
+			perf = 0;
+
+			preempt_disable();
+			j0 = jiffies;
+			while ((j1 = jiffies) == j0)
+				cpu_relax();
+			while (time_before(jiffies,
+					    j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {
+				(*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs);
+				perf++;
+			}
+			preempt_enable();
+
+			if (perf > bestgenperf) {
+				bestgenperf = perf;
+				best = *algo;
+			}
+			pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name,
+			       (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
+
+			if (!(*algo)->xor_syndrome)
+				continue;
+
+			perf = 0;
+
+			preempt_disable();
+			j0 = jiffies;
+			while ((j1 = jiffies) == j0)
+				cpu_relax();
+			while (time_before(jiffies,
+					    j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {
+				(*algo)->xor_syndrome(disks, start, stop,
+						      PAGE_SIZE, *dptrs);
+				perf++;
+			}
+			preempt_enable();
+
+			if (best == *algo)
+				bestxorperf = perf;
+
+			pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name,
+				(perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1));
+		}
+	}
+
+	if (best) {
+		pr_info("raid6: using algorithm %s gen() %ld MB/s\n",
+		       best->name,
+		       (bestgenperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
+		if (best->xor_syndrome)
+			pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n",
+			       (bestxorperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1));
+		raid6_call = *best;
+	} else
+		pr_err("raid6: Yikes!  No algorithm found!\n");
+
+	return best;
+}
+
+
+/* Try to pick the best algorithm */
+/* This code uses the gfmul table as convenient data set to abuse */
+
+int __init raid6_select_algo(void)
+{
+	const int disks = (65536/PAGE_SIZE)+2;
+
+	const struct raid6_calls *gen_best;
+	const struct raid6_recov_calls *rec_best;
+	char *syndromes;
+	void *dptrs[(65536/PAGE_SIZE)+2];
+	int i;
+
+	for (i = 0; i < disks-2; i++)
+		dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i;
+
+	/* Normal code - use a 2-page allocation to avoid D$ conflict */
+	syndromes = (void *) __get_free_pages(GFP_KERNEL, 1);
+
+	if (!syndromes) {
+		pr_err("raid6: Yikes!  No memory available.\n");
+		return -ENOMEM;
+	}
+
+	dptrs[disks-2] = syndromes;
+	dptrs[disks-1] = syndromes + PAGE_SIZE;
+
+	/* select raid gen_syndrome function */
+	gen_best = raid6_choose_gen(&dptrs, disks);
+
+	/* select raid recover functions */
+	rec_best = raid6_choose_recov();
+
+	free_pages((unsigned long)syndromes, 1);
+
+	return gen_best && rec_best ? 0 : -EINVAL;
+}
+
+static void raid6_exit(void)
+{
+	do { } while (0);
+}
+
+subsys_initcall(raid6_select_algo);
+module_exit(raid6_exit);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");