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 | |
17 | static struct dma_async_tx_descriptor * |
18 | async_sum_product(struct page *dest, unsigned int d_off, |
19 | struct page **srcs, unsigned int *src_offs, unsigned char *coef, |
20 | size_t len, struct async_submit_ctl *submit) |
21 | { |
22 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, |
23 | &dest, 1, srcs, 2, len); |
24 | struct dma_device *dma = chan ? chan->device : NULL; |
25 | struct dmaengine_unmap_data *unmap = NULL; |
26 | const u8 *amul, *bmul; |
27 | u8 ax, bx; |
28 | u8 *a, *b, *c; |
29 | |
30 | if (dma) |
31 | unmap = dmaengine_get_unmap_data(dev: dma->dev, nr: 3, GFP_NOWAIT); |
32 | |
33 | if (unmap) { |
34 | struct device *dev = dma->dev; |
35 | dma_addr_t pq[2]; |
36 | struct dma_async_tx_descriptor *tx; |
37 | enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P; |
38 | |
39 | if (submit->flags & ASYNC_TX_FENCE) |
40 | dma_flags |= DMA_PREP_FENCE; |
41 | unmap->addr[0] = dma_map_page(dev, srcs[0], src_offs[0], |
42 | len, DMA_TO_DEVICE); |
43 | unmap->addr[1] = dma_map_page(dev, srcs[1], src_offs[1], |
44 | len, DMA_TO_DEVICE); |
45 | unmap->to_cnt = 2; |
46 | |
47 | unmap->addr[2] = dma_map_page(dev, dest, d_off, |
48 | len, DMA_BIDIRECTIONAL); |
49 | unmap->bidi_cnt = 1; |
50 | /* engine only looks at Q, but expects it to follow P */ |
51 | pq[1] = unmap->addr[2]; |
52 | |
53 | unmap->len = len; |
54 | tx = dma->device_prep_dma_pq(chan, pq, unmap->addr, 2, coef, |
55 | len, dma_flags); |
56 | if (tx) { |
57 | dma_set_unmap(tx, unmap); |
58 | async_tx_submit(chan, tx, submit); |
59 | dmaengine_unmap_put(unmap); |
60 | return tx; |
61 | } |
62 | |
63 | /* could not get a descriptor, unmap and fall through to |
64 | * the synchronous path |
65 | */ |
66 | dmaengine_unmap_put(unmap); |
67 | } |
68 | |
69 | /* run the operation synchronously */ |
70 | async_tx_quiesce(tx: &submit->depend_tx); |
71 | amul = raid6_gfmul[coef[0]]; |
72 | bmul = raid6_gfmul[coef[1]]; |
73 | a = page_address(srcs[0]) + src_offs[0]; |
74 | b = page_address(srcs[1]) + src_offs[1]; |
75 | c = page_address(dest) + d_off; |
76 | |
77 | while (len--) { |
78 | ax = amul[*a++]; |
79 | bx = bmul[*b++]; |
80 | *c++ = ax ^ bx; |
81 | } |
82 | |
83 | return NULL; |
84 | } |
85 | |
86 | static struct dma_async_tx_descriptor * |
87 | async_mult(struct page *dest, unsigned int d_off, struct page *src, |
88 | unsigned int s_off, u8 coef, size_t len, |
89 | struct async_submit_ctl *submit) |
90 | { |
91 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, |
92 | &dest, 1, &src, 1, len); |
93 | struct dma_device *dma = chan ? chan->device : NULL; |
94 | struct dmaengine_unmap_data *unmap = NULL; |
95 | const u8 *qmul; /* Q multiplier table */ |
96 | u8 *d, *s; |
97 | |
98 | if (dma) |
99 | unmap = dmaengine_get_unmap_data(dev: dma->dev, nr: 3, GFP_NOWAIT); |
100 | |
101 | if (unmap) { |
102 | dma_addr_t dma_dest[2]; |
103 | struct device *dev = dma->dev; |
104 | struct dma_async_tx_descriptor *tx; |
105 | enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P; |
106 | |
107 | if (submit->flags & ASYNC_TX_FENCE) |
108 | dma_flags |= DMA_PREP_FENCE; |
109 | unmap->addr[0] = dma_map_page(dev, src, s_off, |
110 | len, DMA_TO_DEVICE); |
111 | unmap->to_cnt++; |
112 | unmap->addr[1] = dma_map_page(dev, dest, d_off, |
113 | len, DMA_BIDIRECTIONAL); |
114 | dma_dest[1] = unmap->addr[1]; |
115 | unmap->bidi_cnt++; |
116 | unmap->len = len; |
117 | |
118 | /* this looks funny, but the engine looks for Q at |
119 | * dma_dest[1] and ignores dma_dest[0] as a dest |
120 | * due to DMA_PREP_PQ_DISABLE_P |
121 | */ |
122 | tx = dma->device_prep_dma_pq(chan, dma_dest, unmap->addr, |
123 | 1, &coef, len, dma_flags); |
124 | |
125 | if (tx) { |
126 | dma_set_unmap(tx, unmap); |
127 | dmaengine_unmap_put(unmap); |
128 | async_tx_submit(chan, tx, submit); |
129 | return tx; |
130 | } |
131 | |
132 | /* could not get a descriptor, unmap and fall through to |
133 | * the synchronous path |
134 | */ |
135 | dmaengine_unmap_put(unmap); |
136 | } |
137 | |
138 | /* no channel available, or failed to allocate a descriptor, so |
139 | * perform the operation synchronously |
140 | */ |
141 | async_tx_quiesce(tx: &submit->depend_tx); |
142 | qmul = raid6_gfmul[coef]; |
143 | d = page_address(dest) + d_off; |
144 | s = page_address(src) + s_off; |
145 | |
146 | while (len--) |
147 | *d++ = qmul[*s++]; |
148 | |
149 | return NULL; |
150 | } |
151 | |
152 | static struct dma_async_tx_descriptor * |
153 | __2data_recov_4(int disks, size_t bytes, int faila, int failb, |
154 | struct page **blocks, unsigned int *offs, |
155 | struct async_submit_ctl *submit) |
156 | { |
157 | struct dma_async_tx_descriptor *tx = NULL; |
158 | struct page *p, *q, *a, *b; |
159 | unsigned int p_off, q_off, a_off, b_off; |
160 | struct page *srcs[2]; |
161 | unsigned int src_offs[2]; |
162 | unsigned char coef[2]; |
163 | enum async_tx_flags flags = submit->flags; |
164 | dma_async_tx_callback cb_fn = submit->cb_fn; |
165 | void *cb_param = submit->cb_param; |
166 | void *scribble = submit->scribble; |
167 | |
168 | p = blocks[disks-2]; |
169 | p_off = offs[disks-2]; |
170 | q = blocks[disks-1]; |
171 | q_off = offs[disks-1]; |
172 | |
173 | a = blocks[faila]; |
174 | a_off = offs[faila]; |
175 | b = blocks[failb]; |
176 | b_off = offs[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 | src_offs[0] = p_off; |
182 | srcs[1] = q; |
183 | src_offs[1] = q_off; |
184 | coef[0] = raid6_gfexi[failb-faila]; |
185 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; |
186 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
187 | tx = async_sum_product(dest: b, d_off: b_off, srcs, src_offs, coef, len: bytes, submit); |
188 | |
189 | /* Dy = P+Pxy+Dx */ |
190 | srcs[0] = p; |
191 | src_offs[0] = p_off; |
192 | srcs[1] = b; |
193 | src_offs[1] = b_off; |
194 | init_async_submit(args: submit, flags: flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn, |
195 | cb_param, scribble); |
196 | tx = async_xor_offs(dest: a, offset: a_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
197 | |
198 | return tx; |
199 | |
200 | } |
201 | |
202 | static struct dma_async_tx_descriptor * |
203 | __2data_recov_5(int disks, size_t bytes, int faila, int failb, |
204 | struct page **blocks, unsigned int *offs, |
205 | struct async_submit_ctl *submit) |
206 | { |
207 | struct dma_async_tx_descriptor *tx = NULL; |
208 | struct page *p, *q, *g, *dp, *dq; |
209 | unsigned int p_off, q_off, g_off, dp_off, dq_off; |
210 | struct page *srcs[2]; |
211 | unsigned int src_offs[2]; |
212 | unsigned char coef[2]; |
213 | enum async_tx_flags flags = submit->flags; |
214 | dma_async_tx_callback cb_fn = submit->cb_fn; |
215 | void *cb_param = submit->cb_param; |
216 | void *scribble = submit->scribble; |
217 | int good_srcs, good, i; |
218 | |
219 | good_srcs = 0; |
220 | good = -1; |
221 | for (i = 0; i < disks-2; i++) { |
222 | if (blocks[i] == NULL) |
223 | continue; |
224 | if (i == faila || i == failb) |
225 | continue; |
226 | good = i; |
227 | good_srcs++; |
228 | } |
229 | BUG_ON(good_srcs > 1); |
230 | |
231 | p = blocks[disks-2]; |
232 | p_off = offs[disks-2]; |
233 | q = blocks[disks-1]; |
234 | q_off = offs[disks-1]; |
235 | g = blocks[good]; |
236 | g_off = offs[good]; |
237 | |
238 | /* Compute syndrome with zero for the missing data pages |
239 | * Use the dead data pages as temporary storage for delta p and |
240 | * delta q |
241 | */ |
242 | dp = blocks[faila]; |
243 | dp_off = offs[faila]; |
244 | dq = blocks[failb]; |
245 | dq_off = offs[failb]; |
246 | |
247 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
248 | tx = async_memcpy(dest: dp, src: g, dest_offset: dp_off, src_offset: g_off, len: bytes, submit); |
249 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
250 | tx = async_mult(dest: dq, d_off: dq_off, src: g, s_off: g_off, |
251 | coef: raid6_gfexp[good], len: bytes, submit); |
252 | |
253 | /* compute P + Pxy */ |
254 | srcs[0] = dp; |
255 | src_offs[0] = dp_off; |
256 | srcs[1] = p; |
257 | src_offs[1] = p_off; |
258 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
259 | NULL, NULL, scribble); |
260 | tx = async_xor_offs(dest: dp, offset: dp_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
261 | |
262 | /* compute Q + Qxy */ |
263 | srcs[0] = dq; |
264 | src_offs[0] = dq_off; |
265 | srcs[1] = q; |
266 | src_offs[1] = q_off; |
267 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
268 | NULL, NULL, scribble); |
269 | tx = async_xor_offs(dest: dq, offset: dq_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
270 | |
271 | /* Dx = A*(P+Pxy) + B*(Q+Qxy) */ |
272 | srcs[0] = dp; |
273 | src_offs[0] = dp_off; |
274 | srcs[1] = dq; |
275 | src_offs[1] = dq_off; |
276 | coef[0] = raid6_gfexi[failb-faila]; |
277 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; |
278 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
279 | tx = async_sum_product(dest: dq, d_off: dq_off, srcs, src_offs, coef, len: bytes, submit); |
280 | |
281 | /* Dy = P+Pxy+Dx */ |
282 | srcs[0] = dp; |
283 | src_offs[0] = dp_off; |
284 | srcs[1] = dq; |
285 | src_offs[1] = dq_off; |
286 | init_async_submit(args: submit, flags: flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
287 | cb_param, scribble); |
288 | tx = async_xor_offs(dest: dp, offset: dp_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
289 | |
290 | return tx; |
291 | } |
292 | |
293 | static struct dma_async_tx_descriptor * |
294 | __2data_recov_n(int disks, size_t bytes, int faila, int failb, |
295 | struct page **blocks, unsigned int *offs, |
296 | struct async_submit_ctl *submit) |
297 | { |
298 | struct dma_async_tx_descriptor *tx = NULL; |
299 | struct page *p, *q, *dp, *dq; |
300 | unsigned int p_off, q_off, dp_off, dq_off; |
301 | struct page *srcs[2]; |
302 | unsigned int src_offs[2]; |
303 | unsigned char coef[2]; |
304 | enum async_tx_flags flags = submit->flags; |
305 | dma_async_tx_callback cb_fn = submit->cb_fn; |
306 | void *cb_param = submit->cb_param; |
307 | void *scribble = submit->scribble; |
308 | |
309 | p = blocks[disks-2]; |
310 | p_off = offs[disks-2]; |
311 | q = blocks[disks-1]; |
312 | q_off = offs[disks-1]; |
313 | |
314 | /* Compute syndrome with zero for the missing data pages |
315 | * Use the dead data pages as temporary storage for |
316 | * delta p and delta q |
317 | */ |
318 | dp = blocks[faila]; |
319 | dp_off = offs[faila]; |
320 | blocks[faila] = NULL; |
321 | blocks[disks-2] = dp; |
322 | offs[disks-2] = dp_off; |
323 | dq = blocks[failb]; |
324 | dq_off = offs[failb]; |
325 | blocks[failb] = NULL; |
326 | blocks[disks-1] = dq; |
327 | offs[disks-1] = dq_off; |
328 | |
329 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
330 | tx = async_gen_syndrome(blocks, offsets: offs, src_cnt: disks, len: bytes, submit); |
331 | |
332 | /* Restore pointer table */ |
333 | blocks[faila] = dp; |
334 | offs[faila] = dp_off; |
335 | blocks[failb] = dq; |
336 | offs[failb] = dq_off; |
337 | blocks[disks-2] = p; |
338 | offs[disks-2] = p_off; |
339 | blocks[disks-1] = q; |
340 | offs[disks-1] = q_off; |
341 | |
342 | /* compute P + Pxy */ |
343 | srcs[0] = dp; |
344 | src_offs[0] = dp_off; |
345 | srcs[1] = p; |
346 | src_offs[1] = p_off; |
347 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
348 | NULL, NULL, scribble); |
349 | tx = async_xor_offs(dest: dp, offset: dp_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
350 | |
351 | /* compute Q + Qxy */ |
352 | srcs[0] = dq; |
353 | src_offs[0] = dq_off; |
354 | srcs[1] = q; |
355 | src_offs[1] = q_off; |
356 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
357 | NULL, NULL, scribble); |
358 | tx = async_xor_offs(dest: dq, offset: dq_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
359 | |
360 | /* Dx = A*(P+Pxy) + B*(Q+Qxy) */ |
361 | srcs[0] = dp; |
362 | src_offs[0] = dp_off; |
363 | srcs[1] = dq; |
364 | src_offs[1] = dq_off; |
365 | coef[0] = raid6_gfexi[failb-faila]; |
366 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; |
367 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
368 | tx = async_sum_product(dest: dq, d_off: dq_off, srcs, src_offs, coef, len: bytes, submit); |
369 | |
370 | /* Dy = P+Pxy+Dx */ |
371 | srcs[0] = dp; |
372 | src_offs[0] = dp_off; |
373 | srcs[1] = dq; |
374 | src_offs[1] = dq_off; |
375 | init_async_submit(args: submit, flags: flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
376 | cb_param, scribble); |
377 | tx = async_xor_offs(dest: dp, offset: dp_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
378 | |
379 | return tx; |
380 | } |
381 | |
382 | /** |
383 | * async_raid6_2data_recov - asynchronously calculate two missing data blocks |
384 | * @disks: number of disks in the RAID-6 array |
385 | * @bytes: block size |
386 | * @faila: first failed drive index |
387 | * @failb: second failed drive index |
388 | * @blocks: array of source pointers where the last two entries are p and q |
389 | * @offs: array of offset for pages in blocks |
390 | * @submit: submission/completion modifiers |
391 | */ |
392 | struct dma_async_tx_descriptor * |
393 | async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb, |
394 | struct page **blocks, unsigned int *offs, |
395 | struct async_submit_ctl *submit) |
396 | { |
397 | void *scribble = submit->scribble; |
398 | int non_zero_srcs, i; |
399 | |
400 | BUG_ON(faila == failb); |
401 | if (failb < faila) |
402 | swap(faila, failb); |
403 | |
404 | pr_debug("%s: disks: %d len: %zu\n" , __func__, disks, bytes); |
405 | |
406 | /* if a dma resource is not available or a scribble buffer is not |
407 | * available punt to the synchronous path. In the 'dma not |
408 | * available' case be sure to use the scribble buffer to |
409 | * preserve the content of 'blocks' as the caller intended. |
410 | */ |
411 | if (!async_dma_find_channel(DMA_PQ) || !scribble) { |
412 | void **ptrs = scribble ? scribble : (void **) blocks; |
413 | |
414 | async_tx_quiesce(tx: &submit->depend_tx); |
415 | for (i = 0; i < disks; i++) |
416 | if (blocks[i] == NULL) |
417 | ptrs[i] = (void *) raid6_empty_zero_page; |
418 | else |
419 | ptrs[i] = page_address(blocks[i]) + offs[i]; |
420 | |
421 | raid6_2data_recov(disks, bytes, faila, failb, ptrs); |
422 | |
423 | async_tx_sync_epilog(submit); |
424 | |
425 | return NULL; |
426 | } |
427 | |
428 | non_zero_srcs = 0; |
429 | for (i = 0; i < disks-2 && non_zero_srcs < 4; i++) |
430 | if (blocks[i]) |
431 | non_zero_srcs++; |
432 | switch (non_zero_srcs) { |
433 | case 0: |
434 | case 1: |
435 | /* There must be at least 2 sources - the failed devices. */ |
436 | BUG(); |
437 | |
438 | case 2: |
439 | /* dma devices do not uniformly understand a zero source pq |
440 | * operation (in contrast to the synchronous case), so |
441 | * explicitly handle the special case of a 4 disk array with |
442 | * both data disks missing. |
443 | */ |
444 | return __2data_recov_4(disks, bytes, faila, failb, |
445 | blocks, offs, submit); |
446 | case 3: |
447 | /* dma devices do not uniformly understand a single |
448 | * source pq operation (in contrast to the synchronous |
449 | * case), so explicitly handle the special case of a 5 disk |
450 | * array with 2 of 3 data disks missing. |
451 | */ |
452 | return __2data_recov_5(disks, bytes, faila, failb, |
453 | blocks, offs, submit); |
454 | default: |
455 | return __2data_recov_n(disks, bytes, faila, failb, |
456 | blocks, offs, submit); |
457 | } |
458 | } |
459 | EXPORT_SYMBOL_GPL(async_raid6_2data_recov); |
460 | |
461 | /** |
462 | * async_raid6_datap_recov - asynchronously calculate a data and the 'p' block |
463 | * @disks: number of disks in the RAID-6 array |
464 | * @bytes: block size |
465 | * @faila: failed drive index |
466 | * @blocks: array of source pointers where the last two entries are p and q |
467 | * @offs: array of offset for pages in blocks |
468 | * @submit: submission/completion modifiers |
469 | */ |
470 | struct dma_async_tx_descriptor * |
471 | async_raid6_datap_recov(int disks, size_t bytes, int faila, |
472 | struct page **blocks, unsigned int *offs, |
473 | struct async_submit_ctl *submit) |
474 | { |
475 | struct dma_async_tx_descriptor *tx = NULL; |
476 | struct page *p, *q, *dq; |
477 | unsigned int p_off, q_off, dq_off; |
478 | u8 coef; |
479 | enum async_tx_flags flags = submit->flags; |
480 | dma_async_tx_callback cb_fn = submit->cb_fn; |
481 | void *cb_param = submit->cb_param; |
482 | void *scribble = submit->scribble; |
483 | int good_srcs, good, i; |
484 | struct page *srcs[2]; |
485 | unsigned int src_offs[2]; |
486 | |
487 | pr_debug("%s: disks: %d len: %zu\n" , __func__, disks, bytes); |
488 | |
489 | /* if a dma resource is not available or a scribble buffer is not |
490 | * available punt to the synchronous path. In the 'dma not |
491 | * available' case be sure to use the scribble buffer to |
492 | * preserve the content of 'blocks' as the caller intended. |
493 | */ |
494 | if (!async_dma_find_channel(DMA_PQ) || !scribble) { |
495 | void **ptrs = scribble ? scribble : (void **) blocks; |
496 | |
497 | async_tx_quiesce(tx: &submit->depend_tx); |
498 | for (i = 0; i < disks; i++) |
499 | if (blocks[i] == NULL) |
500 | ptrs[i] = (void*)raid6_empty_zero_page; |
501 | else |
502 | ptrs[i] = page_address(blocks[i]) + offs[i]; |
503 | |
504 | raid6_datap_recov(disks, bytes, faila, ptrs); |
505 | |
506 | async_tx_sync_epilog(submit); |
507 | |
508 | return NULL; |
509 | } |
510 | |
511 | good_srcs = 0; |
512 | good = -1; |
513 | for (i = 0; i < disks-2; i++) { |
514 | if (i == faila) |
515 | continue; |
516 | if (blocks[i]) { |
517 | good = i; |
518 | good_srcs++; |
519 | if (good_srcs > 1) |
520 | break; |
521 | } |
522 | } |
523 | BUG_ON(good_srcs == 0); |
524 | |
525 | p = blocks[disks-2]; |
526 | p_off = offs[disks-2]; |
527 | q = blocks[disks-1]; |
528 | q_off = offs[disks-1]; |
529 | |
530 | /* Compute syndrome with zero for the missing data page |
531 | * Use the dead data page as temporary storage for delta q |
532 | */ |
533 | dq = blocks[faila]; |
534 | dq_off = offs[faila]; |
535 | blocks[faila] = NULL; |
536 | blocks[disks-1] = dq; |
537 | offs[disks-1] = dq_off; |
538 | |
539 | /* in the 4-disk case we only need to perform a single source |
540 | * multiplication with the one good data block. |
541 | */ |
542 | if (good_srcs == 1) { |
543 | struct page *g = blocks[good]; |
544 | unsigned int g_off = offs[good]; |
545 | |
546 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, |
547 | scribble); |
548 | tx = async_memcpy(dest: p, src: g, dest_offset: p_off, src_offset: g_off, len: bytes, submit); |
549 | |
550 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, |
551 | scribble); |
552 | tx = async_mult(dest: dq, d_off: dq_off, src: g, s_off: g_off, |
553 | coef: raid6_gfexp[good], len: bytes, submit); |
554 | } else { |
555 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, |
556 | scribble); |
557 | tx = async_gen_syndrome(blocks, offsets: offs, src_cnt: disks, len: bytes, submit); |
558 | } |
559 | |
560 | /* Restore pointer table */ |
561 | blocks[faila] = dq; |
562 | offs[faila] = dq_off; |
563 | blocks[disks-1] = q; |
564 | offs[disks-1] = q_off; |
565 | |
566 | /* calculate g^{-faila} */ |
567 | coef = raid6_gfinv[raid6_gfexp[faila]]; |
568 | |
569 | srcs[0] = dq; |
570 | src_offs[0] = dq_off; |
571 | srcs[1] = q; |
572 | src_offs[1] = q_off; |
573 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
574 | NULL, NULL, scribble); |
575 | tx = async_xor_offs(dest: dq, offset: dq_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
576 | |
577 | init_async_submit(args: submit, flags: ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
578 | tx = async_mult(dest: dq, d_off: dq_off, src: dq, s_off: dq_off, coef, len: bytes, submit); |
579 | |
580 | srcs[0] = p; |
581 | src_offs[0] = p_off; |
582 | srcs[1] = dq; |
583 | src_offs[1] = dq_off; |
584 | init_async_submit(args: submit, flags: flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
585 | cb_param, scribble); |
586 | tx = async_xor_offs(dest: p, offset: p_off, src_list: srcs, src_offset: src_offs, src_cnt: 2, len: bytes, submit); |
587 | |
588 | return tx; |
589 | } |
590 | EXPORT_SYMBOL_GPL(async_raid6_datap_recov); |
591 | |
592 | MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>" ); |
593 | MODULE_DESCRIPTION("asynchronous RAID-6 recovery api" ); |
594 | MODULE_LICENSE("GPL" ); |
595 | |