// 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");