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