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-rw-r--r--lib/raid6/algos.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
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+++ b/lib/raid6/algos.c
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+/* -*- 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
+#ifdef CONFIG_AS_AVX512
+ &raid6_avx512x1,
+ &raid6_avx512x2,
+#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
+#ifdef CONFIG_AS_AVX512
+ &raid6_avx512x1,
+ &raid6_avx512x2,
+ &raid6_avx512x4,
+#endif
+#endif
+#ifdef CONFIG_ALTIVEC
+ &raid6_altivec1,
+ &raid6_altivec2,
+ &raid6_altivec4,
+ &raid6_altivec8,
+ &raid6_vpermxor1,
+ &raid6_vpermxor2,
+ &raid6_vpermxor4,
+ &raid6_vpermxor8,
+#endif
+#if defined(CONFIG_S390)
+ &raid6_s390vx8,
+#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_AVX512
+ &raid6_recov_avx512,
+#endif
+#ifdef CONFIG_AS_AVX2
+ &raid6_recov_avx2,
+#endif
+#ifdef CONFIG_AS_SSSE3
+ &raid6_recov_ssse3,
+#endif
+#ifdef CONFIG_S390
+ &raid6_recov_s390xc,
+#endif
+#if defined(CONFIG_KERNEL_MODE_NEON)
+ &raid6_recov_neon,
+#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");
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