1/*
2 * asynchronous raid6 recovery self test
3 * Copyright (c) 2009, Intel Corporation.
4 *
5 * based on drivers/md/raid6test/test.c:
6 * 	Copyright 2002-2007 H. Peter Anvin
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 */
22#include <linux/async_tx.h>
23#include <linux/gfp.h>
24#include <linux/mm.h>
25#include <linux/random.h>
26#include <linux/module.h>
27
28#undef pr
29#define pr(fmt, args...) pr_info("raid6test: " fmt, ##args)
30
31#define NDISKS 64 /* Including P and Q */
32
33static struct page *dataptrs[NDISKS];
34static addr_conv_t addr_conv[NDISKS];
35static struct page *data[NDISKS+3];
36static struct page *spare;
37static struct page *recovi;
38static struct page *recovj;
39
40static void callback(void *param)
41{
42	struct completion *cmp = param;
43
44	complete(cmp);
45}
46
47static void makedata(int disks)
48{
49	int i;
50
51	for (i = 0; i < disks; i++) {
52		prandom_bytes(page_address(data[i]), PAGE_SIZE);
53		dataptrs[i] = data[i];
54	}
55}
56
57static char disk_type(int d, int disks)
58{
59	if (d == disks - 2)
60		return 'P';
61	else if (d == disks - 1)
62		return 'Q';
63	else
64		return 'D';
65}
66
67/* Recover two failed blocks. */
68static void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, struct page **ptrs)
69{
70	struct async_submit_ctl submit;
71	struct completion cmp;
72	struct dma_async_tx_descriptor *tx = NULL;
73	enum sum_check_flags result = ~0;
74
75	if (faila > failb)
76		swap(faila, failb);
77
78	if (failb == disks-1) {
79		if (faila == disks-2) {
80			/* P+Q failure.  Just rebuild the syndrome. */
81			init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
82			tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
83		} else {
84			struct page *blocks[disks];
85			struct page *dest;
86			int count = 0;
87			int i;
88
89			/* data+Q failure.  Reconstruct data from P,
90			 * then rebuild syndrome
91			 */
92			for (i = disks; i-- ; ) {
93				if (i == faila || i == failb)
94					continue;
95				blocks[count++] = ptrs[i];
96			}
97			dest = ptrs[faila];
98			init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
99					  NULL, NULL, addr_conv);
100			tx = async_xor(dest, blocks, 0, count, bytes, &submit);
101
102			init_async_submit(&submit, 0, tx, NULL, NULL, addr_conv);
103			tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
104		}
105	} else {
106		if (failb == disks-2) {
107			/* data+P failure. */
108			init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
109			tx = async_raid6_datap_recov(disks, bytes, faila, ptrs, &submit);
110		} else {
111			/* data+data failure. */
112			init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
113			tx = async_raid6_2data_recov(disks, bytes, faila, failb, ptrs, &submit);
114		}
115	}
116	init_completion(&cmp);
117	init_async_submit(&submit, ASYNC_TX_ACK, tx, callback, &cmp, addr_conv);
118	tx = async_syndrome_val(ptrs, 0, disks, bytes, &result, spare, &submit);
119	async_tx_issue_pending(tx);
120
121	if (wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000)) == 0)
122		pr("%s: timeout! (faila: %d failb: %d disks: %d)\n",
123		   __func__, faila, failb, disks);
124
125	if (result != 0)
126		pr("%s: validation failure! faila: %d failb: %d sum_check_flags: %x\n",
127		   __func__, faila, failb, result);
128}
129
130static int test_disks(int i, int j, int disks)
131{
132	int erra, errb;
133
134	memset(page_address(recovi), 0xf0, PAGE_SIZE);
135	memset(page_address(recovj), 0xba, PAGE_SIZE);
136
137	dataptrs[i] = recovi;
138	dataptrs[j] = recovj;
139
140	raid6_dual_recov(disks, PAGE_SIZE, i, j, dataptrs);
141
142	erra = memcmp(page_address(data[i]), page_address(recovi), PAGE_SIZE);
143	errb = memcmp(page_address(data[j]), page_address(recovj), PAGE_SIZE);
144
145	pr("%s(%d, %d): faila=%3d(%c)  failb=%3d(%c)  %s\n",
146	   __func__, i, j, i, disk_type(i, disks), j, disk_type(j, disks),
147	   (!erra && !errb) ? "OK" : !erra ? "ERRB" : !errb ? "ERRA" : "ERRAB");
148
149	dataptrs[i] = data[i];
150	dataptrs[j] = data[j];
151
152	return erra || errb;
153}
154
155static int test(int disks, int *tests)
156{
157	struct dma_async_tx_descriptor *tx;
158	struct async_submit_ctl submit;
159	struct completion cmp;
160	int err = 0;
161	int i, j;
162
163	recovi = data[disks];
164	recovj = data[disks+1];
165	spare  = data[disks+2];
166
167	makedata(disks);
168
169	/* Nuke syndromes */
170	memset(page_address(data[disks-2]), 0xee, PAGE_SIZE);
171	memset(page_address(data[disks-1]), 0xee, PAGE_SIZE);
172
173	/* Generate assumed good syndrome */
174	init_completion(&cmp);
175	init_async_submit(&submit, ASYNC_TX_ACK, NULL, callback, &cmp, addr_conv);
176	tx = async_gen_syndrome(dataptrs, 0, disks, PAGE_SIZE, &submit);
177	async_tx_issue_pending(tx);
178
179	if (wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000)) == 0) {
180		pr("error: initial gen_syndrome(%d) timed out\n", disks);
181		return 1;
182	}
183
184	pr("testing the %d-disk case...\n", disks);
185	for (i = 0; i < disks-1; i++)
186		for (j = i+1; j < disks; j++) {
187			(*tests)++;
188			err += test_disks(i, j, disks);
189		}
190
191	return err;
192}
193
194
195static int raid6_test(void)
196{
197	int err = 0;
198	int tests = 0;
199	int i;
200
201	for (i = 0; i < NDISKS+3; i++) {
202		data[i] = alloc_page(GFP_KERNEL);
203		if (!data[i]) {
204			while (i--)
205				put_page(data[i]);
206			return -ENOMEM;
207		}
208	}
209
210	/* the 4-disk and 5-disk cases are special for the recovery code */
211	if (NDISKS > 4)
212		err += test(4, &tests);
213	if (NDISKS > 5)
214		err += test(5, &tests);
215	/* the 11 and 12 disk cases are special for ioatdma (p-disabled
216	 * q-continuation without extended descriptor)
217	 */
218	if (NDISKS > 12) {
219		err += test(11, &tests);
220		err += test(12, &tests);
221	}
222
223	/* the 24 disk case is special for ioatdma as it is the boudary point
224	 * at which it needs to switch from 8-source ops to 16-source
225	 * ops for continuation (assumes DMA_HAS_PQ_CONTINUE is not set)
226	 */
227	if (NDISKS > 24)
228		err += test(24, &tests);
229
230	err += test(NDISKS, &tests);
231
232	pr("\n");
233	pr("complete (%d tests, %d failure%s)\n",
234	   tests, err, err == 1 ? "" : "s");
235
236	for (i = 0; i < NDISKS+3; i++)
237		put_page(data[i]);
238
239	return 0;
240}
241
242static void raid6_test_exit(void)
243{
244}
245
246/* when compiled-in wait for drivers to load first (assumes dma drivers
247 * are also compliled-in)
248 */
249late_initcall(raid6_test);
250module_exit(raid6_test_exit);
251MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>");
252MODULE_DESCRIPTION("asynchronous RAID-6 recovery self tests");
253MODULE_LICENSE("GPL");
254