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0a82a623 DW |
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 | ||
29 | static struct dma_async_tx_descriptor * | |
30 | async_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 | ||
0403e382 DW |
47 | if (submit->flags & ASYNC_TX_FENCE) |
48 | dma_flags |= DMA_PREP_FENCE; | |
0a82a623 DW |
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 | ||
60 | /* run the operation synchronously */ | |
61 | async_tx_quiesce(&submit->depend_tx); | |
62 | amul = raid6_gfmul[coef[0]]; | |
63 | bmul = raid6_gfmul[coef[1]]; | |
64 | a = page_address(srcs[0]); | |
65 | b = page_address(srcs[1]); | |
66 | c = page_address(dest); | |
67 | ||
68 | while (len--) { | |
69 | ax = amul[*a++]; | |
70 | bx = bmul[*b++]; | |
71 | *c++ = ax ^ bx; | |
72 | } | |
73 | ||
74 | return NULL; | |
75 | } | |
76 | ||
77 | static struct dma_async_tx_descriptor * | |
78 | async_mult(struct page *dest, struct page *src, u8 coef, size_t len, | |
79 | struct async_submit_ctl *submit) | |
80 | { | |
81 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, | |
82 | &dest, 1, &src, 1, len); | |
83 | struct dma_device *dma = chan ? chan->device : NULL; | |
84 | const u8 *qmul; /* Q multiplier table */ | |
85 | u8 *d, *s; | |
86 | ||
87 | if (dma) { | |
88 | dma_addr_t dma_dest[2]; | |
89 | dma_addr_t dma_src[1]; | |
90 | struct device *dev = dma->dev; | |
91 | struct dma_async_tx_descriptor *tx; | |
92 | enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P; | |
93 | ||
0403e382 DW |
94 | if (submit->flags & ASYNC_TX_FENCE) |
95 | dma_flags |= DMA_PREP_FENCE; | |
0a82a623 DW |
96 | dma_dest[1] = dma_map_page(dev, dest, 0, len, DMA_BIDIRECTIONAL); |
97 | dma_src[0] = dma_map_page(dev, src, 0, len, DMA_TO_DEVICE); | |
98 | tx = dma->device_prep_dma_pq(chan, dma_dest, dma_src, 1, &coef, | |
99 | len, dma_flags); | |
100 | if (tx) { | |
101 | async_tx_submit(chan, tx, submit); | |
102 | return tx; | |
103 | } | |
104 | } | |
105 | ||
106 | /* no channel available, or failed to allocate a descriptor, so | |
107 | * perform the operation synchronously | |
108 | */ | |
109 | async_tx_quiesce(&submit->depend_tx); | |
110 | qmul = raid6_gfmul[coef]; | |
111 | d = page_address(dest); | |
112 | s = page_address(src); | |
113 | ||
114 | while (len--) | |
115 | *d++ = qmul[*s++]; | |
116 | ||
117 | return NULL; | |
118 | } | |
119 | ||
120 | static struct dma_async_tx_descriptor * | |
121 | __2data_recov_4(size_t bytes, int faila, int failb, struct page **blocks, | |
122 | struct async_submit_ctl *submit) | |
123 | { | |
124 | struct dma_async_tx_descriptor *tx = NULL; | |
125 | struct page *p, *q, *a, *b; | |
126 | struct page *srcs[2]; | |
127 | unsigned char coef[2]; | |
128 | enum async_tx_flags flags = submit->flags; | |
129 | dma_async_tx_callback cb_fn = submit->cb_fn; | |
130 | void *cb_param = submit->cb_param; | |
131 | void *scribble = submit->scribble; | |
132 | ||
133 | p = blocks[4-2]; | |
134 | q = blocks[4-1]; | |
135 | ||
136 | a = blocks[faila]; | |
137 | b = blocks[failb]; | |
138 | ||
139 | /* in the 4 disk case P + Pxy == P and Q + Qxy == Q */ | |
140 | /* Dx = A*(P+Pxy) + B*(Q+Qxy) */ | |
141 | srcs[0] = p; | |
142 | srcs[1] = q; | |
143 | coef[0] = raid6_gfexi[failb-faila]; | |
144 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; | |
0403e382 | 145 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
0a82a623 DW |
146 | tx = async_sum_product(b, srcs, coef, bytes, submit); |
147 | ||
148 | /* Dy = P+Pxy+Dx */ | |
149 | srcs[0] = p; | |
150 | srcs[1] = b; | |
151 | init_async_submit(submit, flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn, | |
152 | cb_param, scribble); | |
153 | tx = async_xor(a, srcs, 0, 2, bytes, submit); | |
154 | ||
155 | return tx; | |
156 | ||
157 | } | |
158 | ||
159 | static struct dma_async_tx_descriptor * | |
160 | __2data_recov_5(size_t bytes, int faila, int failb, struct page **blocks, | |
161 | struct async_submit_ctl *submit) | |
162 | { | |
163 | struct dma_async_tx_descriptor *tx = NULL; | |
164 | struct page *p, *q, *g, *dp, *dq; | |
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 | int uninitialized_var(good); | |
172 | int i; | |
173 | ||
174 | for (i = 0; i < 3; i++) { | |
175 | if (i == faila || i == failb) | |
176 | continue; | |
177 | else { | |
178 | good = i; | |
179 | break; | |
180 | } | |
181 | } | |
182 | BUG_ON(i >= 3); | |
183 | ||
184 | p = blocks[5-2]; | |
185 | q = blocks[5-1]; | |
186 | g = blocks[good]; | |
187 | ||
188 | /* Compute syndrome with zero for the missing data pages | |
189 | * Use the dead data pages as temporary storage for delta p and | |
190 | * delta q | |
191 | */ | |
192 | dp = blocks[faila]; | |
193 | dq = blocks[failb]; | |
194 | ||
0403e382 | 195 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
0a82a623 | 196 | tx = async_memcpy(dp, g, 0, 0, bytes, submit); |
0403e382 | 197 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
0a82a623 DW |
198 | tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit); |
199 | ||
200 | /* compute P + Pxy */ | |
201 | srcs[0] = dp; | |
202 | srcs[1] = p; | |
0403e382 DW |
203 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
204 | NULL, NULL, scribble); | |
0a82a623 DW |
205 | tx = async_xor(dp, srcs, 0, 2, bytes, submit); |
206 | ||
207 | /* compute Q + Qxy */ | |
208 | srcs[0] = dq; | |
209 | srcs[1] = q; | |
0403e382 DW |
210 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
211 | NULL, NULL, scribble); | |
0a82a623 DW |
212 | tx = async_xor(dq, srcs, 0, 2, bytes, submit); |
213 | ||
214 | /* Dx = A*(P+Pxy) + B*(Q+Qxy) */ | |
215 | srcs[0] = dp; | |
216 | srcs[1] = dq; | |
217 | coef[0] = raid6_gfexi[failb-faila]; | |
218 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; | |
0403e382 | 219 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
0a82a623 DW |
220 | tx = async_sum_product(dq, srcs, coef, bytes, submit); |
221 | ||
222 | /* Dy = P+Pxy+Dx */ | |
223 | srcs[0] = dp; | |
224 | srcs[1] = dq; | |
225 | init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, | |
226 | cb_param, scribble); | |
227 | tx = async_xor(dp, srcs, 0, 2, bytes, submit); | |
228 | ||
229 | return tx; | |
230 | } | |
231 | ||
232 | static struct dma_async_tx_descriptor * | |
233 | __2data_recov_n(int disks, size_t bytes, int faila, int failb, | |
234 | struct page **blocks, struct async_submit_ctl *submit) | |
235 | { | |
236 | struct dma_async_tx_descriptor *tx = NULL; | |
237 | struct page *p, *q, *dp, *dq; | |
238 | struct page *srcs[2]; | |
239 | unsigned char coef[2]; | |
240 | enum async_tx_flags flags = submit->flags; | |
241 | dma_async_tx_callback cb_fn = submit->cb_fn; | |
242 | void *cb_param = submit->cb_param; | |
243 | void *scribble = submit->scribble; | |
244 | ||
245 | p = blocks[disks-2]; | |
246 | q = blocks[disks-1]; | |
247 | ||
248 | /* Compute syndrome with zero for the missing data pages | |
249 | * Use the dead data pages as temporary storage for | |
250 | * delta p and delta q | |
251 | */ | |
252 | dp = blocks[faila]; | |
253 | blocks[faila] = (void *)raid6_empty_zero_page; | |
254 | blocks[disks-2] = dp; | |
255 | dq = blocks[failb]; | |
256 | blocks[failb] = (void *)raid6_empty_zero_page; | |
257 | blocks[disks-1] = dq; | |
258 | ||
0403e382 | 259 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
0a82a623 DW |
260 | tx = async_gen_syndrome(blocks, 0, disks, bytes, submit); |
261 | ||
262 | /* Restore pointer table */ | |
263 | blocks[faila] = dp; | |
264 | blocks[failb] = dq; | |
265 | blocks[disks-2] = p; | |
266 | blocks[disks-1] = q; | |
267 | ||
268 | /* compute P + Pxy */ | |
269 | srcs[0] = dp; | |
270 | srcs[1] = p; | |
0403e382 DW |
271 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
272 | NULL, NULL, scribble); | |
0a82a623 DW |
273 | tx = async_xor(dp, srcs, 0, 2, bytes, submit); |
274 | ||
275 | /* compute Q + Qxy */ | |
276 | srcs[0] = dq; | |
277 | srcs[1] = q; | |
0403e382 DW |
278 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
279 | NULL, NULL, scribble); | |
0a82a623 DW |
280 | tx = async_xor(dq, srcs, 0, 2, bytes, submit); |
281 | ||
282 | /* Dx = A*(P+Pxy) + B*(Q+Qxy) */ | |
283 | srcs[0] = dp; | |
284 | srcs[1] = dq; | |
285 | coef[0] = raid6_gfexi[failb-faila]; | |
286 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; | |
0403e382 | 287 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
0a82a623 DW |
288 | tx = async_sum_product(dq, srcs, coef, bytes, submit); |
289 | ||
290 | /* Dy = P+Pxy+Dx */ | |
291 | srcs[0] = dp; | |
292 | srcs[1] = dq; | |
293 | init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, | |
294 | cb_param, scribble); | |
295 | tx = async_xor(dp, srcs, 0, 2, bytes, submit); | |
296 | ||
297 | return tx; | |
298 | } | |
299 | ||
300 | /** | |
301 | * async_raid6_2data_recov - asynchronously calculate two missing data blocks | |
302 | * @disks: number of disks in the RAID-6 array | |
303 | * @bytes: block size | |
304 | * @faila: first failed drive index | |
305 | * @failb: second failed drive index | |
306 | * @blocks: array of source pointers where the last two entries are p and q | |
307 | * @submit: submission/completion modifiers | |
308 | */ | |
309 | struct dma_async_tx_descriptor * | |
310 | async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb, | |
311 | struct page **blocks, struct async_submit_ctl *submit) | |
312 | { | |
313 | BUG_ON(faila == failb); | |
314 | if (failb < faila) | |
315 | swap(faila, failb); | |
316 | ||
317 | pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); | |
318 | ||
319 | /* we need to preserve the contents of 'blocks' for the async | |
320 | * case, so punt to synchronous if a scribble buffer is not available | |
321 | */ | |
322 | if (!submit->scribble) { | |
323 | void **ptrs = (void **) blocks; | |
324 | int i; | |
325 | ||
326 | async_tx_quiesce(&submit->depend_tx); | |
327 | for (i = 0; i < disks; i++) | |
328 | ptrs[i] = page_address(blocks[i]); | |
329 | ||
330 | raid6_2data_recov(disks, bytes, faila, failb, ptrs); | |
331 | ||
332 | async_tx_sync_epilog(submit); | |
333 | ||
334 | return NULL; | |
335 | } | |
336 | ||
337 | switch (disks) { | |
338 | case 4: | |
339 | /* dma devices do not uniformly understand a zero source pq | |
340 | * operation (in contrast to the synchronous case), so | |
341 | * explicitly handle the 4 disk special case | |
342 | */ | |
343 | return __2data_recov_4(bytes, faila, failb, blocks, submit); | |
344 | case 5: | |
345 | /* dma devices do not uniformly understand a single | |
346 | * source pq operation (in contrast to the synchronous | |
347 | * case), so explicitly handle the 5 disk special case | |
348 | */ | |
349 | return __2data_recov_5(bytes, faila, failb, blocks, submit); | |
350 | default: | |
351 | return __2data_recov_n(disks, bytes, faila, failb, blocks, submit); | |
352 | } | |
353 | } | |
354 | EXPORT_SYMBOL_GPL(async_raid6_2data_recov); | |
355 | ||
356 | /** | |
357 | * async_raid6_datap_recov - asynchronously calculate a data and the 'p' block | |
358 | * @disks: number of disks in the RAID-6 array | |
359 | * @bytes: block size | |
360 | * @faila: failed drive index | |
361 | * @blocks: array of source pointers where the last two entries are p and q | |
362 | * @submit: submission/completion modifiers | |
363 | */ | |
364 | struct dma_async_tx_descriptor * | |
365 | async_raid6_datap_recov(int disks, size_t bytes, int faila, | |
366 | struct page **blocks, struct async_submit_ctl *submit) | |
367 | { | |
368 | struct dma_async_tx_descriptor *tx = NULL; | |
369 | struct page *p, *q, *dq; | |
370 | u8 coef; | |
371 | enum async_tx_flags flags = submit->flags; | |
372 | dma_async_tx_callback cb_fn = submit->cb_fn; | |
373 | void *cb_param = submit->cb_param; | |
374 | void *scribble = submit->scribble; | |
375 | struct page *srcs[2]; | |
376 | ||
377 | pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); | |
378 | ||
379 | /* we need to preserve the contents of 'blocks' for the async | |
380 | * case, so punt to synchronous if a scribble buffer is not available | |
381 | */ | |
382 | if (!scribble) { | |
383 | void **ptrs = (void **) blocks; | |
384 | int i; | |
385 | ||
386 | async_tx_quiesce(&submit->depend_tx); | |
387 | for (i = 0; i < disks; i++) | |
388 | ptrs[i] = page_address(blocks[i]); | |
389 | ||
390 | raid6_datap_recov(disks, bytes, faila, ptrs); | |
391 | ||
392 | async_tx_sync_epilog(submit); | |
393 | ||
394 | return NULL; | |
395 | } | |
396 | ||
397 | p = blocks[disks-2]; | |
398 | q = blocks[disks-1]; | |
399 | ||
400 | /* Compute syndrome with zero for the missing data page | |
401 | * Use the dead data page as temporary storage for delta q | |
402 | */ | |
403 | dq = blocks[faila]; | |
404 | blocks[faila] = (void *)raid6_empty_zero_page; | |
405 | blocks[disks-1] = dq; | |
406 | ||
407 | /* in the 4 disk case we only need to perform a single source | |
408 | * multiplication | |
409 | */ | |
410 | if (disks == 4) { | |
411 | int good = faila == 0 ? 1 : 0; | |
412 | struct page *g = blocks[good]; | |
413 | ||
0403e382 DW |
414 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
415 | scribble); | |
0a82a623 DW |
416 | tx = async_memcpy(p, g, 0, 0, bytes, submit); |
417 | ||
0403e382 DW |
418 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
419 | scribble); | |
0a82a623 DW |
420 | tx = async_mult(dq, g, raid6_gfexp[good], bytes, submit); |
421 | } else { | |
0403e382 DW |
422 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
423 | scribble); | |
0a82a623 DW |
424 | tx = async_gen_syndrome(blocks, 0, disks, bytes, submit); |
425 | } | |
426 | ||
427 | /* Restore pointer table */ | |
428 | blocks[faila] = dq; | |
429 | blocks[disks-1] = q; | |
430 | ||
431 | /* calculate g^{-faila} */ | |
432 | coef = raid6_gfinv[raid6_gfexp[faila]]; | |
433 | ||
434 | srcs[0] = dq; | |
435 | srcs[1] = q; | |
0403e382 DW |
436 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
437 | NULL, NULL, scribble); | |
0a82a623 DW |
438 | tx = async_xor(dq, srcs, 0, 2, bytes, submit); |
439 | ||
0403e382 | 440 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
0a82a623 DW |
441 | tx = async_mult(dq, dq, coef, bytes, submit); |
442 | ||
443 | srcs[0] = p; | |
444 | srcs[1] = dq; | |
445 | init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, | |
446 | cb_param, scribble); | |
447 | tx = async_xor(p, srcs, 0, 2, bytes, submit); | |
448 | ||
449 | return tx; | |
450 | } | |
451 | EXPORT_SYMBOL_GPL(async_raid6_datap_recov); | |
452 | ||
453 | MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>"); | |
454 | MODULE_DESCRIPTION("asynchronous RAID-6 recovery api"); | |
455 | MODULE_LICENSE("GPL"); |