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