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fd534e9b | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
0a82a623 DW |
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 | |
0a82a623 DW |
8 | */ |
9 | #include <linux/kernel.h> | |
10 | #include <linux/interrupt.h> | |
4bb33cc8 | 11 | #include <linux/module.h> |
0a82a623 DW |
12 | #include <linux/dma-mapping.h> |
13 | #include <linux/raid/pq.h> | |
14 | #include <linux/async_tx.h> | |
3bbdd498 | 15 | #include <linux/dmaengine.h> |
0a82a623 DW |
16 | |
17 | static struct dma_async_tx_descriptor * | |
4f86ff55 YY |
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) | |
0a82a623 DW |
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; | |
3bbdd498 | 25 | struct dmaengine_unmap_data *unmap = NULL; |
0a82a623 DW |
26 | const u8 *amul, *bmul; |
27 | u8 ax, bx; | |
28 | u8 *a, *b, *c; | |
29 | ||
3bbdd498 | 30 | if (dma) |
b02bab6b | 31 | unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT); |
3bbdd498 DW |
32 | |
33 | if (unmap) { | |
0a82a623 | 34 | struct device *dev = dma->dev; |
3bbdd498 | 35 | dma_addr_t pq[2]; |
0a82a623 | 36 | struct dma_async_tx_descriptor *tx; |
0776ae7b | 37 | enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P; |
0a82a623 | 38 | |
0403e382 DW |
39 | if (submit->flags & ASYNC_TX_FENCE) |
40 | dma_flags |= DMA_PREP_FENCE; | |
4f86ff55 YY |
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); | |
3bbdd498 DW |
45 | unmap->to_cnt = 2; |
46 | ||
4f86ff55 YY |
47 | unmap->addr[2] = dma_map_page(dev, dest, d_off, |
48 | len, DMA_BIDIRECTIONAL); | |
3bbdd498 DW |
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, | |
0a82a623 DW |
55 | len, dma_flags); |
56 | if (tx) { | |
3bbdd498 | 57 | dma_set_unmap(tx, unmap); |
0a82a623 | 58 | async_tx_submit(chan, tx, submit); |
3bbdd498 | 59 | dmaengine_unmap_put(unmap); |
0a82a623 DW |
60 | return tx; |
61 | } | |
1f6672d4 DW |
62 | |
63 | /* could not get a descriptor, unmap and fall through to | |
64 | * the synchronous path | |
65 | */ | |
3bbdd498 | 66 | dmaengine_unmap_put(unmap); |
0a82a623 DW |
67 | } |
68 | ||
69 | /* run the operation synchronously */ | |
70 | async_tx_quiesce(&submit->depend_tx); | |
71 | amul = raid6_gfmul[coef[0]]; | |
72 | bmul = raid6_gfmul[coef[1]]; | |
4f86ff55 YY |
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; | |
0a82a623 DW |
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 * | |
4f86ff55 YY |
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) | |
0a82a623 DW |
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; | |
3bbdd498 | 94 | struct dmaengine_unmap_data *unmap = NULL; |
0a82a623 DW |
95 | const u8 *qmul; /* Q multiplier table */ |
96 | u8 *d, *s; | |
97 | ||
3bbdd498 | 98 | if (dma) |
b02bab6b | 99 | unmap = dmaengine_get_unmap_data(dma->dev, 3, GFP_NOWAIT); |
3bbdd498 DW |
100 | |
101 | if (unmap) { | |
0a82a623 | 102 | dma_addr_t dma_dest[2]; |
0a82a623 DW |
103 | struct device *dev = dma->dev; |
104 | struct dma_async_tx_descriptor *tx; | |
0776ae7b | 105 | enum dma_ctrl_flags dma_flags = DMA_PREP_PQ_DISABLE_P; |
0a82a623 | 106 | |
0403e382 DW |
107 | if (submit->flags & ASYNC_TX_FENCE) |
108 | dma_flags |= DMA_PREP_FENCE; | |
4f86ff55 YY |
109 | unmap->addr[0] = dma_map_page(dev, src, s_off, |
110 | len, DMA_TO_DEVICE); | |
3bbdd498 | 111 | unmap->to_cnt++; |
4f86ff55 YY |
112 | unmap->addr[1] = dma_map_page(dev, dest, d_off, |
113 | len, DMA_BIDIRECTIONAL); | |
3bbdd498 DW |
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 | ||
0a82a623 | 125 | if (tx) { |
3bbdd498 DW |
126 | dma_set_unmap(tx, unmap); |
127 | dmaengine_unmap_put(unmap); | |
0a82a623 DW |
128 | async_tx_submit(chan, tx, submit); |
129 | return tx; | |
130 | } | |
1f6672d4 DW |
131 | |
132 | /* could not get a descriptor, unmap and fall through to | |
133 | * the synchronous path | |
134 | */ | |
3bbdd498 | 135 | dmaengine_unmap_put(unmap); |
0a82a623 DW |
136 | } |
137 | ||
138 | /* no channel available, or failed to allocate a descriptor, so | |
139 | * perform the operation synchronously | |
140 | */ | |
141 | async_tx_quiesce(&submit->depend_tx); | |
142 | qmul = raid6_gfmul[coef]; | |
4f86ff55 YY |
143 | d = page_address(dest) + d_off; |
144 | s = page_address(src) + s_off; | |
0a82a623 DW |
145 | |
146 | while (len--) | |
147 | *d++ = qmul[*s++]; | |
148 | ||
149 | return NULL; | |
150 | } | |
151 | ||
152 | static struct dma_async_tx_descriptor * | |
da17bf43 | 153 | __2data_recov_4(int disks, size_t bytes, int faila, int failb, |
4f86ff55 YY |
154 | struct page **blocks, unsigned int *offs, |
155 | struct async_submit_ctl *submit) | |
0a82a623 DW |
156 | { |
157 | struct dma_async_tx_descriptor *tx = NULL; | |
158 | struct page *p, *q, *a, *b; | |
4f86ff55 | 159 | unsigned int p_off, q_off, a_off, b_off; |
0a82a623 | 160 | struct page *srcs[2]; |
4f86ff55 | 161 | unsigned int src_offs[2]; |
0a82a623 DW |
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 | ||
da17bf43 | 168 | p = blocks[disks-2]; |
4f86ff55 | 169 | p_off = offs[disks-2]; |
da17bf43 | 170 | q = blocks[disks-1]; |
4f86ff55 | 171 | q_off = offs[disks-1]; |
0a82a623 DW |
172 | |
173 | a = blocks[faila]; | |
4f86ff55 | 174 | a_off = offs[faila]; |
0a82a623 | 175 | b = blocks[failb]; |
4f86ff55 | 176 | b_off = offs[failb]; |
0a82a623 DW |
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; | |
4f86ff55 | 181 | src_offs[0] = p_off; |
0a82a623 | 182 | srcs[1] = q; |
4f86ff55 | 183 | src_offs[1] = q_off; |
0a82a623 DW |
184 | coef[0] = raid6_gfexi[failb-faila]; |
185 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; | |
0403e382 | 186 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
4f86ff55 | 187 | tx = async_sum_product(b, b_off, srcs, src_offs, coef, bytes, submit); |
0a82a623 DW |
188 | |
189 | /* Dy = P+Pxy+Dx */ | |
190 | srcs[0] = p; | |
4f86ff55 | 191 | src_offs[0] = p_off; |
0a82a623 | 192 | srcs[1] = b; |
4f86ff55 | 193 | src_offs[1] = b_off; |
0a82a623 DW |
194 | init_async_submit(submit, flags | ASYNC_TX_XOR_ZERO_DST, tx, cb_fn, |
195 | cb_param, scribble); | |
4f86ff55 | 196 | tx = async_xor_offs(a, a_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
197 | |
198 | return tx; | |
199 | ||
200 | } | |
201 | ||
202 | static struct dma_async_tx_descriptor * | |
da17bf43 | 203 | __2data_recov_5(int disks, size_t bytes, int faila, int failb, |
4f86ff55 YY |
204 | struct page **blocks, unsigned int *offs, |
205 | struct async_submit_ctl *submit) | |
0a82a623 DW |
206 | { |
207 | struct dma_async_tx_descriptor *tx = NULL; | |
208 | struct page *p, *q, *g, *dp, *dq; | |
4f86ff55 | 209 | unsigned int p_off, q_off, g_off, dp_off, dq_off; |
0a82a623 | 210 | struct page *srcs[2]; |
4f86ff55 | 211 | unsigned int src_offs[2]; |
0a82a623 DW |
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; | |
da17bf43 | 217 | int good_srcs, good, i; |
0a82a623 | 218 | |
da17bf43 DW |
219 | good_srcs = 0; |
220 | good = -1; | |
221 | for (i = 0; i < disks-2; i++) { | |
222 | if (blocks[i] == NULL) | |
223 | continue; | |
0a82a623 DW |
224 | if (i == faila || i == failb) |
225 | continue; | |
da17bf43 DW |
226 | good = i; |
227 | good_srcs++; | |
0a82a623 | 228 | } |
da17bf43 | 229 | BUG_ON(good_srcs > 1); |
0a82a623 | 230 | |
da17bf43 | 231 | p = blocks[disks-2]; |
4f86ff55 | 232 | p_off = offs[disks-2]; |
da17bf43 | 233 | q = blocks[disks-1]; |
4f86ff55 | 234 | q_off = offs[disks-1]; |
0a82a623 | 235 | g = blocks[good]; |
4f86ff55 | 236 | g_off = offs[good]; |
0a82a623 DW |
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]; | |
4f86ff55 | 243 | dp_off = offs[faila]; |
0a82a623 | 244 | dq = blocks[failb]; |
4f86ff55 | 245 | dq_off = offs[failb]; |
0a82a623 | 246 | |
0403e382 | 247 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
4f86ff55 | 248 | tx = async_memcpy(dp, g, dp_off, g_off, bytes, submit); |
0403e382 | 249 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
4f86ff55 YY |
250 | tx = async_mult(dq, dq_off, g, g_off, |
251 | raid6_gfexp[good], bytes, submit); | |
0a82a623 DW |
252 | |
253 | /* compute P + Pxy */ | |
254 | srcs[0] = dp; | |
4f86ff55 | 255 | src_offs[0] = dp_off; |
0a82a623 | 256 | srcs[1] = p; |
4f86ff55 | 257 | src_offs[1] = p_off; |
0403e382 DW |
258 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
259 | NULL, NULL, scribble); | |
4f86ff55 | 260 | tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
261 | |
262 | /* compute Q + Qxy */ | |
263 | srcs[0] = dq; | |
4f86ff55 | 264 | src_offs[0] = dq_off; |
0a82a623 | 265 | srcs[1] = q; |
4f86ff55 | 266 | src_offs[1] = q_off; |
0403e382 DW |
267 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
268 | NULL, NULL, scribble); | |
4f86ff55 | 269 | tx = async_xor_offs(dq, dq_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
270 | |
271 | /* Dx = A*(P+Pxy) + B*(Q+Qxy) */ | |
272 | srcs[0] = dp; | |
4f86ff55 | 273 | src_offs[0] = dp_off; |
0a82a623 | 274 | srcs[1] = dq; |
4f86ff55 | 275 | src_offs[1] = dq_off; |
0a82a623 DW |
276 | coef[0] = raid6_gfexi[failb-faila]; |
277 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; | |
0403e382 | 278 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
4f86ff55 | 279 | tx = async_sum_product(dq, dq_off, srcs, src_offs, coef, bytes, submit); |
0a82a623 DW |
280 | |
281 | /* Dy = P+Pxy+Dx */ | |
282 | srcs[0] = dp; | |
4f86ff55 | 283 | src_offs[0] = dp_off; |
0a82a623 | 284 | srcs[1] = dq; |
4f86ff55 | 285 | src_offs[1] = dq_off; |
0a82a623 DW |
286 | init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
287 | cb_param, scribble); | |
4f86ff55 | 288 | tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
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, | |
4f86ff55 YY |
295 | struct page **blocks, unsigned int *offs, |
296 | struct async_submit_ctl *submit) | |
0a82a623 DW |
297 | { |
298 | struct dma_async_tx_descriptor *tx = NULL; | |
299 | struct page *p, *q, *dp, *dq; | |
4f86ff55 | 300 | unsigned int p_off, q_off, dp_off, dq_off; |
0a82a623 | 301 | struct page *srcs[2]; |
4f86ff55 | 302 | unsigned int src_offs[2]; |
0a82a623 DW |
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]; | |
4f86ff55 | 310 | p_off = offs[disks-2]; |
0a82a623 | 311 | q = blocks[disks-1]; |
4f86ff55 | 312 | q_off = offs[disks-1]; |
0a82a623 DW |
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]; | |
4f86ff55 | 319 | dp_off = offs[faila]; |
5dd33c9a | 320 | blocks[faila] = NULL; |
0a82a623 | 321 | blocks[disks-2] = dp; |
4f86ff55 | 322 | offs[disks-2] = dp_off; |
0a82a623 | 323 | dq = blocks[failb]; |
4f86ff55 | 324 | dq_off = offs[failb]; |
5dd33c9a | 325 | blocks[failb] = NULL; |
0a82a623 | 326 | blocks[disks-1] = dq; |
4f86ff55 | 327 | offs[disks-1] = dq_off; |
0a82a623 | 328 | |
0403e382 | 329 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
4f86ff55 | 330 | tx = async_gen_syndrome(blocks, offs, disks, bytes, submit); |
0a82a623 DW |
331 | |
332 | /* Restore pointer table */ | |
333 | blocks[faila] = dp; | |
4f86ff55 | 334 | offs[faila] = dp_off; |
0a82a623 | 335 | blocks[failb] = dq; |
4f86ff55 | 336 | offs[failb] = dq_off; |
0a82a623 | 337 | blocks[disks-2] = p; |
4f86ff55 | 338 | offs[disks-2] = p_off; |
0a82a623 | 339 | blocks[disks-1] = q; |
4f86ff55 | 340 | offs[disks-1] = q_off; |
0a82a623 DW |
341 | |
342 | /* compute P + Pxy */ | |
343 | srcs[0] = dp; | |
4f86ff55 | 344 | src_offs[0] = dp_off; |
0a82a623 | 345 | srcs[1] = p; |
4f86ff55 | 346 | src_offs[1] = p_off; |
0403e382 DW |
347 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
348 | NULL, NULL, scribble); | |
4f86ff55 | 349 | tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
350 | |
351 | /* compute Q + Qxy */ | |
352 | srcs[0] = dq; | |
4f86ff55 | 353 | src_offs[0] = dq_off; |
0a82a623 | 354 | srcs[1] = q; |
4f86ff55 | 355 | src_offs[1] = q_off; |
0403e382 DW |
356 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
357 | NULL, NULL, scribble); | |
4f86ff55 | 358 | tx = async_xor_offs(dq, dq_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
359 | |
360 | /* Dx = A*(P+Pxy) + B*(Q+Qxy) */ | |
361 | srcs[0] = dp; | |
4f86ff55 | 362 | src_offs[0] = dp_off; |
0a82a623 | 363 | srcs[1] = dq; |
4f86ff55 | 364 | src_offs[1] = dq_off; |
0a82a623 DW |
365 | coef[0] = raid6_gfexi[failb-faila]; |
366 | coef[1] = raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]; | |
0403e382 | 367 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
4f86ff55 | 368 | tx = async_sum_product(dq, dq_off, srcs, src_offs, coef, bytes, submit); |
0a82a623 DW |
369 | |
370 | /* Dy = P+Pxy+Dx */ | |
371 | srcs[0] = dp; | |
4f86ff55 | 372 | src_offs[0] = dp_off; |
0a82a623 | 373 | srcs[1] = dq; |
4f86ff55 | 374 | src_offs[1] = dq_off; |
0a82a623 DW |
375 | init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
376 | cb_param, scribble); | |
4f86ff55 | 377 | tx = async_xor_offs(dp, dp_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
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 | |
4f86ff55 | 389 | * @offs: array of offset for pages in blocks |
0a82a623 DW |
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, | |
4f86ff55 YY |
394 | struct page **blocks, unsigned int *offs, |
395 | struct async_submit_ctl *submit) | |
0a82a623 | 396 | { |
5157b4aa | 397 | void *scribble = submit->scribble; |
da17bf43 DW |
398 | int non_zero_srcs, i; |
399 | ||
0a82a623 DW |
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 | ||
5157b4aa DW |
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. | |
0a82a623 | 410 | */ |
5157b4aa DW |
411 | if (!async_dma_find_channel(DMA_PQ) || !scribble) { |
412 | void **ptrs = scribble ? scribble : (void **) blocks; | |
0a82a623 DW |
413 | |
414 | async_tx_quiesce(&submit->depend_tx); | |
415 | for (i = 0; i < disks; i++) | |
5dd33c9a | 416 | if (blocks[i] == NULL) |
da17bf43 | 417 | ptrs[i] = (void *) raid6_empty_zero_page; |
5dd33c9a | 418 | else |
4f86ff55 | 419 | ptrs[i] = page_address(blocks[i]) + offs[i]; |
0a82a623 DW |
420 | |
421 | raid6_2data_recov(disks, bytes, faila, failb, ptrs); | |
422 | ||
423 | async_tx_sync_epilog(submit); | |
424 | ||
425 | return NULL; | |
426 | } | |
427 | ||
da17bf43 DW |
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: | |
0a82a623 DW |
439 | /* dma devices do not uniformly understand a zero source pq |
440 | * operation (in contrast to the synchronous case), so | |
da17bf43 DW |
441 | * explicitly handle the special case of a 4 disk array with |
442 | * both data disks missing. | |
0a82a623 | 443 | */ |
4f86ff55 YY |
444 | return __2data_recov_4(disks, bytes, faila, failb, |
445 | blocks, offs, submit); | |
da17bf43 | 446 | case 3: |
0a82a623 DW |
447 | /* dma devices do not uniformly understand a single |
448 | * source pq operation (in contrast to the synchronous | |
da17bf43 DW |
449 | * case), so explicitly handle the special case of a 5 disk |
450 | * array with 2 of 3 data disks missing. | |
0a82a623 | 451 | */ |
4f86ff55 YY |
452 | return __2data_recov_5(disks, bytes, faila, failb, |
453 | blocks, offs, submit); | |
0a82a623 | 454 | default: |
4f86ff55 YY |
455 | return __2data_recov_n(disks, bytes, faila, failb, |
456 | blocks, offs, submit); | |
0a82a623 DW |
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 | |
4f86ff55 | 467 | * @offs: array of offset for pages in blocks |
0a82a623 DW |
468 | * @submit: submission/completion modifiers |
469 | */ | |
470 | struct dma_async_tx_descriptor * | |
471 | async_raid6_datap_recov(int disks, size_t bytes, int faila, | |
4f86ff55 YY |
472 | struct page **blocks, unsigned int *offs, |
473 | struct async_submit_ctl *submit) | |
0a82a623 DW |
474 | { |
475 | struct dma_async_tx_descriptor *tx = NULL; | |
476 | struct page *p, *q, *dq; | |
4f86ff55 | 477 | unsigned int p_off, q_off, dq_off; |
0a82a623 DW |
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; | |
da17bf43 | 483 | int good_srcs, good, i; |
0a82a623 | 484 | struct page *srcs[2]; |
4f86ff55 | 485 | unsigned int src_offs[2]; |
0a82a623 DW |
486 | |
487 | pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes); | |
488 | ||
5157b4aa DW |
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. | |
0a82a623 | 493 | */ |
5157b4aa DW |
494 | if (!async_dma_find_channel(DMA_PQ) || !scribble) { |
495 | void **ptrs = scribble ? scribble : (void **) blocks; | |
0a82a623 DW |
496 | |
497 | async_tx_quiesce(&submit->depend_tx); | |
498 | for (i = 0; i < disks; i++) | |
5dd33c9a N |
499 | if (blocks[i] == NULL) |
500 | ptrs[i] = (void*)raid6_empty_zero_page; | |
501 | else | |
4f86ff55 | 502 | ptrs[i] = page_address(blocks[i]) + offs[i]; |
0a82a623 DW |
503 | |
504 | raid6_datap_recov(disks, bytes, faila, ptrs); | |
505 | ||
506 | async_tx_sync_epilog(submit); | |
507 | ||
508 | return NULL; | |
509 | } | |
510 | ||
da17bf43 DW |
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 | ||
0a82a623 | 525 | p = blocks[disks-2]; |
4f86ff55 | 526 | p_off = offs[disks-2]; |
0a82a623 | 527 | q = blocks[disks-1]; |
4f86ff55 | 528 | q_off = offs[disks-1]; |
0a82a623 DW |
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]; | |
4f86ff55 | 534 | dq_off = offs[faila]; |
5dd33c9a | 535 | blocks[faila] = NULL; |
0a82a623 | 536 | blocks[disks-1] = dq; |
4f86ff55 | 537 | offs[disks-1] = dq_off; |
0a82a623 | 538 | |
da17bf43 DW |
539 | /* in the 4-disk case we only need to perform a single source |
540 | * multiplication with the one good data block. | |
0a82a623 | 541 | */ |
da17bf43 | 542 | if (good_srcs == 1) { |
0a82a623 | 543 | struct page *g = blocks[good]; |
4f86ff55 | 544 | unsigned int g_off = offs[good]; |
0a82a623 | 545 | |
0403e382 DW |
546 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
547 | scribble); | |
4f86ff55 | 548 | tx = async_memcpy(p, g, p_off, g_off, bytes, submit); |
0a82a623 | 549 | |
0403e382 DW |
550 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
551 | scribble); | |
4f86ff55 YY |
552 | tx = async_mult(dq, dq_off, g, g_off, |
553 | raid6_gfexp[good], bytes, submit); | |
0a82a623 | 554 | } else { |
0403e382 DW |
555 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, |
556 | scribble); | |
4f86ff55 | 557 | tx = async_gen_syndrome(blocks, offs, disks, bytes, submit); |
0a82a623 DW |
558 | } |
559 | ||
560 | /* Restore pointer table */ | |
561 | blocks[faila] = dq; | |
4f86ff55 | 562 | offs[faila] = dq_off; |
0a82a623 | 563 | blocks[disks-1] = q; |
4f86ff55 | 564 | offs[disks-1] = q_off; |
0a82a623 DW |
565 | |
566 | /* calculate g^{-faila} */ | |
567 | coef = raid6_gfinv[raid6_gfexp[faila]]; | |
568 | ||
569 | srcs[0] = dq; | |
4f86ff55 | 570 | src_offs[0] = dq_off; |
0a82a623 | 571 | srcs[1] = q; |
4f86ff55 | 572 | src_offs[1] = q_off; |
0403e382 DW |
573 | init_async_submit(submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, |
574 | NULL, NULL, scribble); | |
4f86ff55 | 575 | tx = async_xor_offs(dq, dq_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 | 576 | |
0403e382 | 577 | init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble); |
4f86ff55 | 578 | tx = async_mult(dq, dq_off, dq, dq_off, coef, bytes, submit); |
0a82a623 DW |
579 | |
580 | srcs[0] = p; | |
4f86ff55 | 581 | src_offs[0] = p_off; |
0a82a623 | 582 | srcs[1] = dq; |
4f86ff55 | 583 | src_offs[1] = dq_off; |
0a82a623 DW |
584 | init_async_submit(submit, flags | ASYNC_TX_XOR_DROP_DST, tx, cb_fn, |
585 | cb_param, scribble); | |
4f86ff55 | 586 | tx = async_xor_offs(p, p_off, srcs, src_offs, 2, bytes, submit); |
0a82a623 DW |
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"); |