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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Asynchronous RAID-6 recovery calculations ASYNC_TX API.
4 * Copyright(c) 2009 Intel Corporation
5 *
6 * based on raid6recov.c:
7 * Copyright 2002 H. Peter Anvin
8 */
9#include <linux/kernel.h>
10#include <linux/interrupt.h>
11#include <linux/module.h>
12#include <linux/dma-mapping.h>
13#include <linux/raid/pq.h>
14#include <linux/async_tx.h>
15#include <linux/dmaengine.h>
16
17static struct dma_async_tx_descriptor *
18async_sum_product(struct page *dest, struct page **srcs, unsigned char *coef,
19 size_t len, struct async_submit_ctl *submit)
20{
21 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
22 &dest, 1, srcs, 2, len);
23 struct dma_device *dma = chan ? chan->device : NULL;
24 struct dmaengine_unmap_data *unmap = NULL;
25 const u8 *amul, *bmul;
26 u8 ax, bx;
27 u8 *a, *b, *c;
28
29 if (dma)
30 unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT);
31
32 if (unmap) {
33 struct device *dev = dma->dev;
34 dma_addr_t pq[2];
35 struct dma_async_tx_descriptor *tx;
36 enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
37
38 if (submit->flags & ASYNC_TX_FENCE)
39 dma_flags |= DMA_PREP_FENCE;
40 unmap->addr[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
41 unmap->addr[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
42 unmap->to_cnt = 2;
43
44 unmap->addr[2] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
45 unmap->bidi_cnt = 1;
46 /* engine only looks at Q, but expects it to follow P */
47 pq[1] = unmap->addr[2];
48
49 unmap->len = len;
50 tx = dma->device_prep_dma_pq(chan, pq, unmap->addr, 2, coef,
51 len, dma_flags);
52 if (tx) {
53 dma_set_unmap(tx, unmap);
54 async_tx_submit(chan, tx, submit);
55 dmaengine_unmap_put(unmap);
56 return tx;
57 }
58
59 /* could not get a descriptor, unmap and fall through to
60 * the synchronous path
61 */
62 dmaengine_unmap_put(unmap);
63 }
64
65 /* run the operation synchronously */
66 async_tx_quiesce(&submit->depend_tx);
67 amul = raid6_gfmul[coef[0]];
68 bmul = raid6_gfmul[coef[1]];
69 a = page_address(srcs[0]);
70 b = page_address(srcs[1]);
71 c = page_address(dest);
72
73 while (len--) {
74 ax = amul[*a++];
75 bx = bmul[*b++];
76 *c++ = ax ^ bx;
77 }
78
79 return NULL;
80}
81
82static struct dma_async_tx_descriptor *
83async_mult(struct page *dest, struct page *src, u8 coef, size_t len,
84 struct async_submit_ctl *submit)
85{
86 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
87 &dest, 1, &src, 1, len);
88 struct dma_device *dma = chan ? chan->device : NULL;
89 struct dmaengine_unmap_data *unmap = NULL;
90 const u8 *qmul; /* Q multiplier table */
91 u8 *d, *s;
92
93 if (dma)
94 unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT);
95
96 if (unmap) {
97 dma_addr_t dma_dest[2];
98 struct device *dev = dma->dev;
99 struct dma_async_tx_descriptor *tx;
100 enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
101
102 if (submit->flags & ASYNC_TX_FENCE)
103 dma_flags |= DMA_PREP_FENCE;
104 unmap->addr[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
105 unmap->to_cnt++;
106 unmap->addr[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
107 dma_dest[1] = unmap->addr[1];
108 unmap->bidi_cnt++;
109 unmap->len = len;
110
111 /* this looks funny, but the engine looks for Q at
112 * dma_dest[1] and ignores dma_dest[0] as a dest
113 * due to DMA_PREP_PQ_DISABLE_P
114 */
115 tx = dma->device_prep_dma_pq(chan, dma_dest, unmap->addr,
116 1, &coef, len, dma_flags);
117
118 if (tx) {
119 dma_set_unmap(tx, unmap);
120 dmaengine_unmap_put(unmap);
121 async_tx_submit(chan, tx, submit);
122 return tx;
123 }
124
125 /* could not get a descriptor, unmap and fall through to
126 * the synchronous path
127 */
128 dmaengine_unmap_put(unmap);
129 }
130
131 /* no channel available, or failed to allocate a descriptor, so
132 * perform the operation synchronously
133 */
134 async_tx_quiesce(&submit->depend_tx);
135 qmul = raid6_gfmul[coef];
136 d = page_address(dest);
137 s = page_address(src);
138
139 while (len--)
140 *d++ = qmul[*s++];
141
142 return NULL;
143}
144
145static struct dma_async_tx_descriptor *
146__2data_recov_4(int disks, size_t bytes, int faila, int failb,
147 struct page **blocks, struct async_submit_ctl *submit)
148{
149 struct dma_async_tx_descriptor *tx = NULL;
150 struct page *p, *q, *a, *b;
151 struct page *srcs[2];
152 unsigned char coef[2];
153 enum async_tx_flags flags = submit->flags;
154 dma_async_tx_callback cb_fn = submit->cb_fn;
155 void *cb_param = submit->cb_param;
156 void *scribble = submit->scribble;
157
158 p = blocks[disks-2];
159 q = blocks[disks-1];
160
161 a = blocks[faila];
162 b = blocks[failb];
163
164 /* in the 4 disk case P + Pxy == P and Q + Qxy == Q */
165 /* Dx = A*(P+Pxy) + B*(Q+Qxy) */
166 srcs[0] = p;
167 srcs[1] = q;
168 coef[0] = raid6_gfexi[failb-faila];
169 coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
170 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
171 tx = async_sum_product(b, srcs, coef, bytes, submit);
172
173 /* Dy = P+Pxy+Dx */
174 srcs[0] = p;
175 srcs[1] = b;
176 init_async_submit(submit, flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn,
177 cb_param, scribble);
178 tx = async_xor(a, srcs, 0, 2, bytes, submit);
179
180 return tx;
181
182}
183
184static struct dma_async_tx_descriptor *
185__2data_recov_5(int disks, size_t bytes, int faila, int failb,
186 struct page **blocks, struct async_submit_ctl *submit)
187{
188 struct dma_async_tx_descriptor *tx = NULL;
189 struct page *p, *q, *g, *dp, *dq;
190 struct page *srcs[2];
191 unsigned char coef[2];
192 enum async_tx_flags flags = submit->flags;
193 dma_async_tx_callback cb_fn = submit->cb_fn;
194 void *cb_param = submit->cb_param;
195 void *scribble = submit->scribble;
196 int good_srcs, good, i;
197
198 good_srcs = 0;
199 good = -1;
200 for (i = 0; i < disks-2; i++) {
201 if (blocks[i] == NULL)
202 continue;
203 if (i == faila || i == failb)
204 continue;
205 good = i;
206 good_srcs++;
207 }
208 BUG_ON(good_srcs > 1);
209
210 p = blocks[disks-2];
211 q = blocks[disks-1];
212 g = blocks[good];
213
214 /* Compute syndrome with zero for the missing data pages
215 * Use the dead data pages as temporary storage for delta p and
216 * delta q
217 */
218 dp = blocks[faila];
219 dq = blocks[failb];
220
221 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
222 tx = async_memcpy(dp, g, 0, 0, bytes, submit);
223 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
224 tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
225
226 /* compute P + Pxy */
227 srcs[0] = dp;
228 srcs[1] = p;
229 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
230 NULL, NULL, scribble);
231 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
232
233 /* compute Q + Qxy */
234 srcs[0] = dq;
235 srcs[1] = q;
236 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
237 NULL, NULL, scribble);
238 tx = async_xor(dq, srcs, 0, 2, bytes, submit);
239
240 /* Dx = A*(P+Pxy) + B*(Q+Qxy) */
241 srcs[0] = dp;
242 srcs[1] = dq;
243 coef[0] = raid6_gfexi[failb-faila];
244 coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
245 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
246 tx = async_sum_product(dq, srcs, coef, bytes, submit);
247
248 /* Dy = P+Pxy+Dx */
249 srcs[0] = dp;
250 srcs[1] = dq;
251 init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
252 cb_param, scribble);
253 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
254
255 return tx;
256}
257
258static struct dma_async_tx_descriptor *
259__2data_recov_n(int disks, size_t bytes, int faila, int failb,
260 struct page **blocks, struct async_submit_ctl *submit)
261{
262 struct dma_async_tx_descriptor *tx = NULL;
263 struct page *p, *q, *dp, *dq;
264 struct page *srcs[2];
265 unsigned char coef[2];
266 enum async_tx_flags flags = submit->flags;
267 dma_async_tx_callback cb_fn = submit->cb_fn;
268 void *cb_param = submit->cb_param;
269 void *scribble = submit->scribble;
270
271 p = blocks[disks-2];
272 q = blocks[disks-1];
273
274 /* Compute syndrome with zero for the missing data pages
275 * Use the dead data pages as temporary storage for
276 * delta p and delta q
277 */
278 dp = blocks[faila];
279 blocks[faila] = NULL;
280 blocks[disks-2] = dp;
281 dq = blocks[failb];
282 blocks[failb] = NULL;
283 blocks[disks-1] = dq;
284
285 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
286 tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
287
288 /* Restore pointer table */
289 blocks[faila] = dp;
290 blocks[failb] = dq;
291 blocks[disks-2] = p;
292 blocks[disks-1] = q;
293
294 /* compute P + Pxy */
295 srcs[0] = dp;
296 srcs[1] = p;
297 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
298 NULL, NULL, scribble);
299 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
300
301 /* compute Q + Qxy */
302 srcs[0] = dq;
303 srcs[1] = q;
304 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
305 NULL, NULL, scribble);
306 tx = async_xor(dq, srcs, 0, 2, bytes, submit);
307
308 /* Dx = A*(P+Pxy) + B*(Q+Qxy) */
309 srcs[0] = dp;
310 srcs[1] = dq;
311 coef[0] = raid6_gfexi[failb-faila];
312 coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
313 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
314 tx = async_sum_product(dq, srcs, coef, bytes, submit);
315
316 /* Dy = P+Pxy+Dx */
317 srcs[0] = dp;
318 srcs[1] = dq;
319 init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
320 cb_param, scribble);
321 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
322
323 return tx;
324}
325
326/**
327 * async_raid6_2data_recov - asynchronously calculate two missing data blocks
328 * @disks: number of disks in the RAID-6 array
329 * @bytes: block size
330 * @faila: first failed drive index
331 * @failb: second failed drive index
332 * @blocks: array of source pointers where the last two entries are p and q
333 * @submit: submission/completion modifiers
334 */
335struct dma_async_tx_descriptor *
336async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
337 struct page **blocks, struct async_submit_ctl *submit)
338{
339 void *scribble = submit->scribble;
340 int non_zero_srcs, i;
341
342 BUG_ON(faila == failb);
343 if (failb < faila)
344 swap(faila, failb);
345
346 pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
347
348 /* if a dma resource is not available or a scribble buffer is not
349 * available punt to the synchronous path. In the 'dma not
350 * available' case be sure to use the scribble buffer to
351 * preserve the content of 'blocks' as the caller intended.
352 */
353 if (!async_dma_find_channel(DMA_PQ) || !scribble) {
354 void **ptrs = scribble ? scribble : (void **) blocks;
355
356 async_tx_quiesce(&submit->depend_tx);
357 for (i = 0; i < disks; i++)
358 if (blocks[i] == NULL)
359 ptrs[i] = (void *) raid6_empty_zero_page;
360 else
361 ptrs[i] = page_address(blocks[i]);
362
363 raid6_2data_recov(disks, bytes, faila, failb, ptrs);
364
365 async_tx_sync_epilog(submit);
366
367 return NULL;
368 }
369
370 non_zero_srcs = 0;
371 for (i = 0; i < disks-2 && non_zero_srcs < 4; i++)
372 if (blocks[i])
373 non_zero_srcs++;
374 switch (non_zero_srcs) {
375 case 0:
376 case 1:
377 /* There must be at least 2 sources - the failed devices. */
378 BUG();
379
380 case 2:
381 /* dma devices do not uniformly understand a zero source pq
382 * operation (in contrast to the synchronous case), so
383 * explicitly handle the special case of a 4 disk array with
384 * both data disks missing.
385 */
386 return __2data_recov_4(disks, bytes, faila, failb, blocks, submit);
387 case 3:
388 /* dma devices do not uniformly understand a single
389 * source pq operation (in contrast to the synchronous
390 * case), so explicitly handle the special case of a 5 disk
391 * array with 2 of 3 data disks missing.
392 */
393 return __2data_recov_5(disks, bytes, faila, failb, blocks, submit);
394 default:
395 return __2data_recov_n(disks, bytes, faila, failb, blocks, submit);
396 }
397}
398EXPORT_SYMBOL_GPL(async_raid6_2data_recov);
399
400/**
401 * async_raid6_datap_recov - asynchronously calculate a data and the 'p' block
402 * @disks: number of disks in the RAID-6 array
403 * @bytes: block size
404 * @faila: failed drive index
405 * @blocks: array of source pointers where the last two entries are p and q
406 * @submit: submission/completion modifiers
407 */
408struct dma_async_tx_descriptor *
409async_raid6_datap_recov(int disks, size_t bytes, int faila,
410 struct page **blocks, struct async_submit_ctl *submit)
411{
412 struct dma_async_tx_descriptor *tx = NULL;
413 struct page *p, *q, *dq;
414 u8 coef;
415 enum async_tx_flags flags = submit->flags;
416 dma_async_tx_callback cb_fn = submit->cb_fn;
417 void *cb_param = submit->cb_param;
418 void *scribble = submit->scribble;
419 int good_srcs, good, i;
420 struct page *srcs[2];
421
422 pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
423
424 /* if a dma resource is not available or a scribble buffer is not
425 * available punt to the synchronous path. In the 'dma not
426 * available' case be sure to use the scribble buffer to
427 * preserve the content of 'blocks' as the caller intended.
428 */
429 if (!async_dma_find_channel(DMA_PQ) || !scribble) {
430 void **ptrs = scribble ? scribble : (void **) blocks;
431
432 async_tx_quiesce(&submit->depend_tx);
433 for (i = 0; i < disks; i++)
434 if (blocks[i] == NULL)
435 ptrs[i] = (void*)raid6_empty_zero_page;
436 else
437 ptrs[i] = page_address(blocks[i]);
438
439 raid6_datap_recov(disks, bytes, faila, ptrs);
440
441 async_tx_sync_epilog(submit);
442
443 return NULL;
444 }
445
446 good_srcs = 0;
447 good = -1;
448 for (i = 0; i < disks-2; i++) {
449 if (i == faila)
450 continue;
451 if (blocks[i]) {
452 good = i;
453 good_srcs++;
454 if (good_srcs > 1)
455 break;
456 }
457 }
458 BUG_ON(good_srcs == 0);
459
460 p = blocks[disks-2];
461 q = blocks[disks-1];
462
463 /* Compute syndrome with zero for the missing data page
464 * Use the dead data page as temporary storage for delta q
465 */
466 dq = blocks[faila];
467 blocks[faila] = NULL;
468 blocks[disks-1] = dq;
469
470 /* in the 4-disk case we only need to perform a single source
471 * multiplication with the one good data block.
472 */
473 if (good_srcs == 1) {
474 struct page *g = blocks[good];
475
476 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
477 scribble);
478 tx = async_memcpy(p, g, 0, 0, bytes, submit);
479
480 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
481 scribble);
482 tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
483 } else {
484 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
485 scribble);
486 tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
487 }
488
489 /* Restore pointer table */
490 blocks[faila] = dq;
491 blocks[disks-1] = q;
492
493 /* calculate g^{-faila} */
494 coef = raid6_gfinv[raid6_gfexp[faila]];
495
496 srcs[0] = dq;
497 srcs[1] = q;
498 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
499 NULL, NULL, scribble);
500 tx = async_xor(dq, srcs, 0, 2, bytes, submit);
501
502 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
503 tx = async_mult(dq, dq, coef, bytes, submit);
504
505 srcs[0] = p;
506 srcs[1] = dq;
507 init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
508 cb_param, scribble);
509 tx = async_xor(p, srcs, 0, 2, bytes, submit);
510
511 return tx;
512}
513EXPORT_SYMBOL_GPL(async_raid6_datap_recov);
514
515MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>");
516MODULE_DESCRIPTION("asynchronous RAID-6 recovery api");
517MODULE_LICENSE("GPL");
1/*
2 * Asynchronous RAID-6 recovery calculations ASYNC_TX API.
3 * Copyright(c) 2009 Intel Corporation
4 *
5 * based on raid6recov.c:
6 * Copyright 2002 H. Peter Anvin
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 * This program is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
16 * more details.
17 *
18 * You should have received a copy of the GNU General Public License along with
19 * this program; if not, write to the Free Software Foundation, Inc., 51
20 * Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 */
23#include <linux/kernel.h>
24#include <linux/interrupt.h>
25#include <linux/module.h>
26#include <linux/dma-mapping.h>
27#include <linux/raid/pq.h>
28#include <linux/async_tx.h>
29#include <linux/dmaengine.h>
30
31static struct dma_async_tx_descriptor *
32async_sum_product(struct page *dest, struct page **srcs, unsigned char *coef,
33 size_t len, struct async_submit_ctl *submit)
34{
35 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
36 &dest, 1, srcs, 2, len);
37 struct dma_device *dma = chan ? chan->device : NULL;
38 struct dmaengine_unmap_data *unmap = NULL;
39 const u8 *amul, *bmul;
40 u8 ax, bx;
41 u8 *a, *b, *c;
42
43 if (dma)
44 unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT);
45
46 if (unmap) {
47 struct device *dev = dma->dev;
48 dma_addr_t pq[2];
49 struct dma_async_tx_descriptor *tx;
50 enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
51
52 if (submit->flags & ASYNC_TX_FENCE)
53 dma_flags |= DMA_PREP_FENCE;
54 unmap->addr[0] = dma_map_page(dev, srcs[0], 0, len, DMA_TO_DEVICE);
55 unmap->addr[1] = dma_map_page(dev, srcs[1], 0, len, DMA_TO_DEVICE);
56 unmap->to_cnt = 2;
57
58 unmap->addr[2] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
59 unmap->bidi_cnt = 1;
60 /* engine only looks at Q, but expects it to follow P */
61 pq[1] = unmap->addr[2];
62
63 unmap->len = len;
64 tx = dma->device_prep_dma_pq(chan, pq, unmap->addr, 2, coef,
65 len, dma_flags);
66 if (tx) {
67 dma_set_unmap(tx, unmap);
68 async_tx_submit(chan, tx, submit);
69 dmaengine_unmap_put(unmap);
70 return tx;
71 }
72
73 /* could not get a descriptor, unmap and fall through to
74 * the synchronous path
75 */
76 dmaengine_unmap_put(unmap);
77 }
78
79 /* run the operation synchronously */
80 async_tx_quiesce(&submit->depend_tx);
81 amul = raid6_gfmul[coef[0]];
82 bmul = raid6_gfmul[coef[1]];
83 a = page_address(srcs[0]);
84 b = page_address(srcs[1]);
85 c = page_address(dest);
86
87 while (len--) {
88 ax = amul[*a++];
89 bx = bmul[*b++];
90 *c++ = ax ^ bx;
91 }
92
93 return NULL;
94}
95
96static struct dma_async_tx_descriptor *
97async_mult(struct page *dest, struct page *src, u8 coef, size_t len,
98 struct async_submit_ctl *submit)
99{
100 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
101 &dest, 1, &src, 1, len);
102 struct dma_device *dma = chan ? chan->device : NULL;
103 struct dmaengine_unmap_data *unmap = NULL;
104 const u8 *qmul; /* Q multiplier table */
105 u8 *d, *s;
106
107 if (dma)
108 unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT);
109
110 if (unmap) {
111 dma_addr_t dma_dest[2];
112 struct device *dev = dma->dev;
113 struct dma_async_tx_descriptor *tx;
114 enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P;
115
116 if (submit->flags & ASYNC_TX_FENCE)
117 dma_flags |= DMA_PREP_FENCE;
118 unmap->addr[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE);
119 unmap->to_cnt++;
120 unmap->addr[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL);
121 dma_dest[1] = unmap->addr[1];
122 unmap->bidi_cnt++;
123 unmap->len = len;
124
125 /* this looks funny, but the engine looks for Q at
126 * dma_dest[1] and ignores dma_dest[0] as a dest
127 * due to DMA_PREP_PQ_DISABLE_P
128 */
129 tx = dma->device_prep_dma_pq(chan, dma_dest, unmap->addr,
130 1, &coef, len, dma_flags);
131
132 if (tx) {
133 dma_set_unmap(tx, unmap);
134 dmaengine_unmap_put(unmap);
135 async_tx_submit(chan, tx, submit);
136 return tx;
137 }
138
139 /* could not get a descriptor, unmap and fall through to
140 * the synchronous path
141 */
142 dmaengine_unmap_put(unmap);
143 }
144
145 /* no channel available, or failed to allocate a descriptor, so
146 * perform the operation synchronously
147 */
148 async_tx_quiesce(&submit->depend_tx);
149 qmul = raid6_gfmul[coef];
150 d = page_address(dest);
151 s = page_address(src);
152
153 while (len--)
154 *d++ = qmul[*s++];
155
156 return NULL;
157}
158
159static struct dma_async_tx_descriptor *
160__2data_recov_4(int disks, size_t bytes, int faila, int failb,
161 struct page **blocks, struct async_submit_ctl *submit)
162{
163 struct dma_async_tx_descriptor *tx = NULL;
164 struct page *p, *q, *a, *b;
165 struct page *srcs[2];
166 unsigned char coef[2];
167 enum async_tx_flags flags = submit->flags;
168 dma_async_tx_callback cb_fn = submit->cb_fn;
169 void *cb_param = submit->cb_param;
170 void *scribble = submit->scribble;
171
172 p = blocks[disks-2];
173 q = blocks[disks-1];
174
175 a = blocks[faila];
176 b = blocks[failb];
177
178 /* in the 4 disk case P + Pxy == P and Q + Qxy == Q */
179 /* Dx = A*(P+Pxy) + B*(Q+Qxy) */
180 srcs[0] = p;
181 srcs[1] = q;
182 coef[0] = raid6_gfexi[failb-faila];
183 coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
184 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
185 tx = async_sum_product(b, srcs, coef, bytes, submit);
186
187 /* Dy = P+Pxy+Dx */
188 srcs[0] = p;
189 srcs[1] = b;
190 init_async_submit(submit, flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn,
191 cb_param, scribble);
192 tx = async_xor(a, srcs, 0, 2, bytes, submit);
193
194 return tx;
195
196}
197
198static struct dma_async_tx_descriptor *
199__2data_recov_5(int disks, size_t bytes, int faila, int failb,
200 struct page **blocks, struct async_submit_ctl *submit)
201{
202 struct dma_async_tx_descriptor *tx = NULL;
203 struct page *p, *q, *g, *dp, *dq;
204 struct page *srcs[2];
205 unsigned char coef[2];
206 enum async_tx_flags flags = submit->flags;
207 dma_async_tx_callback cb_fn = submit->cb_fn;
208 void *cb_param = submit->cb_param;
209 void *scribble = submit->scribble;
210 int good_srcs, good, i;
211
212 good_srcs = 0;
213 good = -1;
214 for (i = 0; i < disks-2; i++) {
215 if (blocks[i] == NULL)
216 continue;
217 if (i == faila || i == failb)
218 continue;
219 good = i;
220 good_srcs++;
221 }
222 BUG_ON(good_srcs > 1);
223
224 p = blocks[disks-2];
225 q = blocks[disks-1];
226 g = blocks[good];
227
228 /* Compute syndrome with zero for the missing data pages
229 * Use the dead data pages as temporary storage for delta p and
230 * delta q
231 */
232 dp = blocks[faila];
233 dq = blocks[failb];
234
235 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
236 tx = async_memcpy(dp, g, 0, 0, bytes, submit);
237 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
238 tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
239
240 /* compute P + Pxy */
241 srcs[0] = dp;
242 srcs[1] = p;
243 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
244 NULL, NULL, scribble);
245 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
246
247 /* compute Q + Qxy */
248 srcs[0] = dq;
249 srcs[1] = q;
250 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
251 NULL, NULL, scribble);
252 tx = async_xor(dq, srcs, 0, 2, bytes, submit);
253
254 /* Dx = A*(P+Pxy) + B*(Q+Qxy) */
255 srcs[0] = dp;
256 srcs[1] = dq;
257 coef[0] = raid6_gfexi[failb-faila];
258 coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
259 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
260 tx = async_sum_product(dq, srcs, coef, bytes, submit);
261
262 /* Dy = P+Pxy+Dx */
263 srcs[0] = dp;
264 srcs[1] = dq;
265 init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
266 cb_param, scribble);
267 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
268
269 return tx;
270}
271
272static struct dma_async_tx_descriptor *
273__2data_recov_n(int disks, size_t bytes, int faila, int failb,
274 struct page **blocks, struct async_submit_ctl *submit)
275{
276 struct dma_async_tx_descriptor *tx = NULL;
277 struct page *p, *q, *dp, *dq;
278 struct page *srcs[2];
279 unsigned char coef[2];
280 enum async_tx_flags flags = submit->flags;
281 dma_async_tx_callback cb_fn = submit->cb_fn;
282 void *cb_param = submit->cb_param;
283 void *scribble = submit->scribble;
284
285 p = blocks[disks-2];
286 q = blocks[disks-1];
287
288 /* Compute syndrome with zero for the missing data pages
289 * Use the dead data pages as temporary storage for
290 * delta p and delta q
291 */
292 dp = blocks[faila];
293 blocks[faila] = NULL;
294 blocks[disks-2] = dp;
295 dq = blocks[failb];
296 blocks[failb] = NULL;
297 blocks[disks-1] = dq;
298
299 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
300 tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
301
302 /* Restore pointer table */
303 blocks[faila] = dp;
304 blocks[failb] = dq;
305 blocks[disks-2] = p;
306 blocks[disks-1] = q;
307
308 /* compute P + Pxy */
309 srcs[0] = dp;
310 srcs[1] = p;
311 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
312 NULL, NULL, scribble);
313 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
314
315 /* compute Q + Qxy */
316 srcs[0] = dq;
317 srcs[1] = q;
318 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
319 NULL, NULL, scribble);
320 tx = async_xor(dq, srcs, 0, 2, bytes, submit);
321
322 /* Dx = A*(P+Pxy) + B*(Q+Qxy) */
323 srcs[0] = dp;
324 srcs[1] = dq;
325 coef[0] = raid6_gfexi[failb-faila];
326 coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]];
327 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
328 tx = async_sum_product(dq, srcs, coef, bytes, submit);
329
330 /* Dy = P+Pxy+Dx */
331 srcs[0] = dp;
332 srcs[1] = dq;
333 init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
334 cb_param, scribble);
335 tx = async_xor(dp, srcs, 0, 2, bytes, submit);
336
337 return tx;
338}
339
340/**
341 * async_raid6_2data_recov - asynchronously calculate two missing data blocks
342 * @disks: number of disks in the RAID-6 array
343 * @bytes: block size
344 * @faila: first failed drive index
345 * @failb: second failed drive index
346 * @blocks: array of source pointers where the last two entries are p and q
347 * @submit: submission/completion modifiers
348 */
349struct dma_async_tx_descriptor *
350async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
351 struct page **blocks, struct async_submit_ctl *submit)
352{
353 void *scribble = submit->scribble;
354 int non_zero_srcs, i;
355
356 BUG_ON(faila == failb);
357 if (failb < faila)
358 swap(faila, failb);
359
360 pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
361
362 /* if a dma resource is not available or a scribble buffer is not
363 * available punt to the synchronous path. In the 'dma not
364 * available' case be sure to use the scribble buffer to
365 * preserve the content of 'blocks' as the caller intended.
366 */
367 if (!async_dma_find_channel(DMA_PQ) || !scribble) {
368 void **ptrs = scribble ? scribble : (void **) blocks;
369
370 async_tx_quiesce(&submit->depend_tx);
371 for (i = 0; i < disks; i++)
372 if (blocks[i] == NULL)
373 ptrs[i] = (void *) raid6_empty_zero_page;
374 else
375 ptrs[i] = page_address(blocks[i]);
376
377 raid6_2data_recov(disks, bytes, faila, failb, ptrs);
378
379 async_tx_sync_epilog(submit);
380
381 return NULL;
382 }
383
384 non_zero_srcs = 0;
385 for (i = 0; i < disks-2 && non_zero_srcs < 4; i++)
386 if (blocks[i])
387 non_zero_srcs++;
388 switch (non_zero_srcs) {
389 case 0:
390 case 1:
391 /* There must be at least 2 sources - the failed devices. */
392 BUG();
393
394 case 2:
395 /* dma devices do not uniformly understand a zero source pq
396 * operation (in contrast to the synchronous case), so
397 * explicitly handle the special case of a 4 disk array with
398 * both data disks missing.
399 */
400 return __2data_recov_4(disks, bytes, faila, failb, blocks, submit);
401 case 3:
402 /* dma devices do not uniformly understand a single
403 * source pq operation (in contrast to the synchronous
404 * case), so explicitly handle the special case of a 5 disk
405 * array with 2 of 3 data disks missing.
406 */
407 return __2data_recov_5(disks, bytes, faila, failb, blocks, submit);
408 default:
409 return __2data_recov_n(disks, bytes, faila, failb, blocks, submit);
410 }
411}
412EXPORT_SYMBOL_GPL(async_raid6_2data_recov);
413
414/**
415 * async_raid6_datap_recov - asynchronously calculate a data and the 'p' block
416 * @disks: number of disks in the RAID-6 array
417 * @bytes: block size
418 * @faila: failed drive index
419 * @blocks: array of source pointers where the last two entries are p and q
420 * @submit: submission/completion modifiers
421 */
422struct dma_async_tx_descriptor *
423async_raid6_datap_recov(int disks, size_t bytes, int faila,
424 struct page **blocks, struct async_submit_ctl *submit)
425{
426 struct dma_async_tx_descriptor *tx = NULL;
427 struct page *p, *q, *dq;
428 u8 coef;
429 enum async_tx_flags flags = submit->flags;
430 dma_async_tx_callback cb_fn = submit->cb_fn;
431 void *cb_param = submit->cb_param;
432 void *scribble = submit->scribble;
433 int good_srcs, good, i;
434 struct page *srcs[2];
435
436 pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
437
438 /* if a dma resource is not available or a scribble buffer is not
439 * available punt to the synchronous path. In the 'dma not
440 * available' case be sure to use the scribble buffer to
441 * preserve the content of 'blocks' as the caller intended.
442 */
443 if (!async_dma_find_channel(DMA_PQ) || !scribble) {
444 void **ptrs = scribble ? scribble : (void **) blocks;
445
446 async_tx_quiesce(&submit->depend_tx);
447 for (i = 0; i < disks; i++)
448 if (blocks[i] == NULL)
449 ptrs[i] = (void*)raid6_empty_zero_page;
450 else
451 ptrs[i] = page_address(blocks[i]);
452
453 raid6_datap_recov(disks, bytes, faila, ptrs);
454
455 async_tx_sync_epilog(submit);
456
457 return NULL;
458 }
459
460 good_srcs = 0;
461 good = -1;
462 for (i = 0; i < disks-2; i++) {
463 if (i == faila)
464 continue;
465 if (blocks[i]) {
466 good = i;
467 good_srcs++;
468 if (good_srcs > 1)
469 break;
470 }
471 }
472 BUG_ON(good_srcs == 0);
473
474 p = blocks[disks-2];
475 q = blocks[disks-1];
476
477 /* Compute syndrome with zero for the missing data page
478 * Use the dead data page as temporary storage for delta q
479 */
480 dq = blocks[faila];
481 blocks[faila] = NULL;
482 blocks[disks-1] = dq;
483
484 /* in the 4-disk case we only need to perform a single source
485 * multiplication with the one good data block.
486 */
487 if (good_srcs == 1) {
488 struct page *g = blocks[good];
489
490 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
491 scribble);
492 tx = async_memcpy(p, g, 0, 0, bytes, submit);
493
494 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
495 scribble);
496 tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit);
497 } else {
498 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
499 scribble);
500 tx = async_gen_syndrome(blocks, 0, disks, bytes, submit);
501 }
502
503 /* Restore pointer table */
504 blocks[faila] = dq;
505 blocks[disks-1] = q;
506
507 /* calculate g^{-faila} */
508 coef = raid6_gfinv[raid6_gfexp[faila]];
509
510 srcs[0] = dq;
511 srcs[1] = q;
512 init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
513 NULL, NULL, scribble);
514 tx = async_xor(dq, srcs, 0, 2, bytes, submit);
515
516 init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
517 tx = async_mult(dq, dq, coef, bytes, submit);
518
519 srcs[0] = p;
520 srcs[1] = dq;
521 init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn,
522 cb_param, scribble);
523 tx = async_xor(p, srcs, 0, 2, bytes, submit);
524
525 return tx;
526}
527EXPORT_SYMBOL_GPL(async_raid6_datap_recov);
528
529MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>");
530MODULE_DESCRIPTION("asynchronous RAID-6 recovery api");
531MODULE_LICENSE("GPL");