1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* -*- linux-c -*- ------------------------------------------------------- *
4 * Copyright 2002 H. Peter Anvin - All Rights Reserved
6 * ----------------------------------------------------------------------- */
11 * Algorithm list and algorithm selection for RAID-6
14 #include <linux/raid/pq.h>
19 #include <linux/module.h>
20 #include <linux/gfp.h>
21 /* In .bss so it's zeroed */
22 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
23 EXPORT_SYMBOL(raid6_empty_zero_page);
26 struct raid6_calls raid6_call;
27 EXPORT_SYMBOL_GPL(raid6_call);
29 const struct raid6_calls * const raid6_algos[] = {
30 #if defined(__i386__) && !defined(__arch_um__)
31 #ifdef CONFIG_AS_AVX512
44 #if defined(__x86_64__) && !defined(__arch_um__)
45 #ifdef CONFIG_AS_AVX512
67 #if defined(CONFIG_S390)
70 #ifdef CONFIG_KERNEL_MODE_NEON
76 #ifdef CONFIG_LOONGARCH
77 #ifdef CONFIG_CPU_HAS_LASX
80 #ifdef CONFIG_CPU_HAS_LSX
91 void (*raid6_2data_recov)(int, size_t, int, int, void **);
92 EXPORT_SYMBOL_GPL(raid6_2data_recov);
94 void (*raid6_datap_recov)(int, size_t, int, void **);
95 EXPORT_SYMBOL_GPL(raid6_datap_recov);
97 const struct raid6_recov_calls *const raid6_recov_algos[] = {
99 #ifdef CONFIG_AS_AVX512
108 #if defined(CONFIG_KERNEL_MODE_NEON)
111 #ifdef CONFIG_LOONGARCH
112 #ifdef CONFIG_CPU_HAS_LASX
115 #ifdef CONFIG_CPU_HAS_LSX
124 #define RAID6_TIME_JIFFIES_LG2 4
126 /* Need more time to be stable in userspace */
127 #define RAID6_TIME_JIFFIES_LG2 9
128 #define time_before(x, y) ((x) < (y))
131 #define RAID6_TEST_DISKS 8
132 #define RAID6_TEST_DISKS_ORDER 3
134 static inline const struct raid6_recov_calls *raid6_choose_recov(void)
136 const struct raid6_recov_calls *const *algo;
137 const struct raid6_recov_calls *best;
139 for (best = NULL, algo = raid6_recov_algos; *algo; algo++)
140 if (!best || (*algo)->priority > best->priority)
141 if (!(*algo)->valid || (*algo)->valid())
145 raid6_2data_recov = best->data2;
146 raid6_datap_recov = best->datap;
148 pr_info("raid6: using %s recovery algorithm\n", best->name);
150 pr_err("raid6: Yikes! No recovery algorithm found!\n");
155 static inline const struct raid6_calls *raid6_choose_gen(
156 void *(*const dptrs)[RAID6_TEST_DISKS], const int disks)
158 unsigned long perf, bestgenperf, j0, j1;
159 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */
160 const struct raid6_calls *const *algo;
161 const struct raid6_calls *best;
163 for (bestgenperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
164 if (!best || (*algo)->priority >= best->priority) {
165 if ((*algo)->valid && !(*algo)->valid())
168 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {
177 while ((j1 = jiffies) == j0)
179 while (time_before(jiffies,
180 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {
181 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs);
186 if (perf > bestgenperf) {
190 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name,
191 (perf * HZ * (disks-2)) >>
192 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2));
197 pr_err("raid6: Yikes! No algorithm found!\n");
203 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {
204 pr_info("raid6: skipped pq benchmark and selected %s\n",
209 pr_info("raid6: using algorithm %s gen() %ld MB/s\n",
211 (bestgenperf * HZ * (disks - 2)) >>
212 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2));
214 if (best->xor_syndrome) {
219 while ((j1 = jiffies) == j0)
221 while (time_before(jiffies,
222 j1 + (1 << RAID6_TIME_JIFFIES_LG2))) {
223 best->xor_syndrome(disks, start, stop,
229 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n",
230 (perf * HZ * (disks - 2)) >>
231 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1));
239 /* Try to pick the best algorithm */
240 /* This code uses the gfmul table as convenient data set to abuse */
242 int __init raid6_select_algo(void)
244 const int disks = RAID6_TEST_DISKS;
246 const struct raid6_calls *gen_best;
247 const struct raid6_recov_calls *rec_best;
249 void *dptrs[RAID6_TEST_DISKS];
252 /* prepare the buffer and fill it circularly with gfmul table */
253 disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER);
255 pr_err("raid6: Yikes! No memory available.\n");
260 for (i = 0; i < disks; i++)
261 dptrs[i] = p + PAGE_SIZE * i;
263 cycle = ((disks - 2) * PAGE_SIZE) / 65536;
264 for (i = 0; i < cycle; i++) {
265 memcpy(p, raid6_gfmul, 65536);
269 if ((disks - 2) * PAGE_SIZE % 65536)
270 memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536);
272 /* select raid gen_syndrome function */
273 gen_best = raid6_choose_gen(&dptrs, disks);
275 /* select raid recover functions */
276 rec_best = raid6_choose_recov();
278 free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER);
280 return gen_best && rec_best ? 0 : -EINVAL;
283 static void raid6_exit(void)
288 subsys_initcall(raid6_select_algo);
289 module_exit(raid6_exit);
290 MODULE_LICENSE("GPL");
291 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");