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linux-brain/lib/raid6/algos.c
Thomas Gleixner dd165a658d treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 48 
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 13 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170858.645641371@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:13 +02:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright 2002 H. Peter Anvin - All Rights Reserved
*
* ----------------------------------------------------------------------- */
/*
* 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(__i386__) && !defined(__arch_um__)
#ifdef CONFIG_AS_AVX512
&raid6_avx512x2,
&raid6_avx512x1,
#endif
#ifdef CONFIG_AS_AVX2
&raid6_avx2x2,
&raid6_avx2x1,
#endif
&raid6_sse2x2,
&raid6_sse2x1,
&raid6_sse1x2,
&raid6_sse1x1,
&raid6_mmxx2,
&raid6_mmxx1,
#endif
#if defined(__x86_64__) && !defined(__arch_um__)
#ifdef CONFIG_AS_AVX512
&raid6_avx512x4,
&raid6_avx512x2,
&raid6_avx512x1,
#endif
#ifdef CONFIG_AS_AVX2
&raid6_avx2x4,
&raid6_avx2x2,
&raid6_avx2x1,
#endif
&raid6_sse2x4,
&raid6_sse2x2,
&raid6_sse2x1,
#endif
#ifdef CONFIG_ALTIVEC
&raid6_vpermxor8,
&raid6_vpermxor4,
&raid6_vpermxor2,
&raid6_vpermxor1,
&raid6_altivec8,
&raid6_altivec4,
&raid6_altivec2,
&raid6_altivec1,
#endif
#if defined(CONFIG_S390)
&raid6_s390vx8,
#endif
#ifdef CONFIG_KERNEL_MODE_NEON
&raid6_neonx8,
&raid6_neonx4,
&raid6_neonx2,
&raid6_neonx1,
#endif
#if defined(__ia64__)
&raid6_intx32,
&raid6_intx16,
#endif
&raid6_intx8,
&raid6_intx4,
&raid6_intx2,
&raid6_intx1,
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;
if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {
best = *algo;
break;
}
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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