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b2f46fd8 DW |
1 | /* |
2 | * Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com> | |
3 | * Copyright(c) 2009 Intel Corporation | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License as published by the Free | |
7 | * Software Foundation; either version 2 of the License, or (at your option) | |
8 | * any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along with | |
16 | * this program; if not, write to the Free Software Foundation, Inc., 59 | |
17 | * Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
18 | * | |
19 | * The full GNU General Public License is included in this distribution in the | |
20 | * file called COPYING. | |
21 | */ | |
22 | #include <linux/kernel.h> | |
23 | #include <linux/interrupt.h> | |
4bb33cc8 | 24 | #include <linux/module.h> |
b2f46fd8 DW |
25 | #include <linux/dma-mapping.h> |
26 | #include <linux/raid/pq.h> | |
27 | #include <linux/async_tx.h> | |
5a0e3ad6 | 28 | #include <linux/gfp.h> |
b2f46fd8 DW |
29 | |
30 | /** | |
030b0772 DW |
31 | * pq_scribble_page - space to hold throwaway P or Q buffer for |
32 | * synchronous gen_syndrome | |
b2f46fd8 | 33 | */ |
030b0772 | 34 | static struct page *pq_scribble_page; |
b2f46fd8 | 35 | |
b2f46fd8 DW |
36 | /* the struct page *blocks[] parameter passed to async_gen_syndrome() |
37 | * and async_syndrome_val() contains the 'P' destination address at | |
38 | * blocks[disks-2] and the 'Q' destination address at blocks[disks-1] | |
39 | * | |
40 | * note: these are macros as they are used as lvalues | |
41 | */ | |
42 | #define P(b, d) (b[d-2]) | |
43 | #define Q(b, d) (b[d-1]) | |
44 | ||
45 | /** | |
46 | * do_async_gen_syndrome - asynchronously calculate P and/or Q | |
47 | */ | |
48 | static __async_inline struct dma_async_tx_descriptor * | |
7476bd79 DW |
49 | do_async_gen_syndrome(struct dma_chan *chan, |
50 | const unsigned char *scfs, int disks, | |
51 | struct dmaengine_unmap_data *unmap, | |
52 | enum dma_ctrl_flags dma_flags, | |
b2f46fd8 DW |
53 | struct async_submit_ctl *submit) |
54 | { | |
55 | struct dma_async_tx_descriptor *tx = NULL; | |
56 | struct dma_device *dma = chan->device; | |
b2f46fd8 DW |
57 | enum async_tx_flags flags_orig = submit->flags; |
58 | dma_async_tx_callback cb_fn_orig = submit->cb_fn; | |
59 | dma_async_tx_callback cb_param_orig = submit->cb_param; | |
60 | int src_cnt = disks - 2; | |
b2f46fd8 DW |
61 | unsigned short pq_src_cnt; |
62 | dma_addr_t dma_dest[2]; | |
63 | int src_off = 0; | |
b2f46fd8 | 64 | |
7476bd79 DW |
65 | if (submit->flags & ASYNC_TX_FENCE) |
66 | dma_flags |= DMA_PREP_FENCE; | |
b2f46fd8 DW |
67 | |
68 | while (src_cnt > 0) { | |
69 | submit->flags = flags_orig; | |
70 | pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags)); | |
71 | /* if we are submitting additional pqs, leave the chain open, | |
72 | * clear the callback parameters, and leave the destination | |
73 | * buffers mapped | |
74 | */ | |
75 | if (src_cnt > pq_src_cnt) { | |
76 | submit->flags &= ~ASYNC_TX_ACK; | |
0403e382 | 77 | submit->flags |= ASYNC_TX_FENCE; |
b2f46fd8 DW |
78 | submit->cb_fn = NULL; |
79 | submit->cb_param = NULL; | |
80 | } else { | |
b2f46fd8 DW |
81 | submit->cb_fn = cb_fn_orig; |
82 | submit->cb_param = cb_param_orig; | |
83 | if (cb_fn_orig) | |
84 | dma_flags |= DMA_PREP_INTERRUPT; | |
85 | } | |
86 | ||
7476bd79 DW |
87 | /* Drivers force forward progress in case they can not provide |
88 | * a descriptor | |
b2f46fd8 DW |
89 | */ |
90 | for (;;) { | |
7476bd79 DW |
91 | dma_dest[0] = unmap->addr[disks - 2]; |
92 | dma_dest[1] = unmap->addr[disks - 1]; | |
b2f46fd8 | 93 | tx = dma->device_prep_dma_pq(chan, dma_dest, |
7476bd79 | 94 | &unmap->addr[src_off], |
b2f46fd8 | 95 | pq_src_cnt, |
7476bd79 | 96 | &scfs[src_off], unmap->len, |
b2f46fd8 DW |
97 | dma_flags); |
98 | if (likely(tx)) | |
99 | break; | |
100 | async_tx_quiesce(&submit->depend_tx); | |
101 | dma_async_issue_pending(chan); | |
102 | } | |
103 | ||
7476bd79 | 104 | dma_set_unmap(tx, unmap); |
b2f46fd8 DW |
105 | async_tx_submit(chan, tx, submit); |
106 | submit->depend_tx = tx; | |
107 | ||
108 | /* drop completed sources */ | |
109 | src_cnt -= pq_src_cnt; | |
110 | src_off += pq_src_cnt; | |
111 | ||
112 | dma_flags |= DMA_PREP_CONTINUE; | |
113 | } | |
114 | ||
115 | return tx; | |
116 | } | |
117 | ||
118 | /** | |
119 | * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome | |
120 | */ | |
121 | static void | |
122 | do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks, | |
123 | size_t len, struct async_submit_ctl *submit) | |
124 | { | |
125 | void **srcs; | |
126 | int i; | |
584acdd4 | 127 | int start = -1, stop = disks - 3; |
b2f46fd8 DW |
128 | |
129 | if (submit->scribble) | |
130 | srcs = submit->scribble; | |
131 | else | |
132 | srcs = (void **) blocks; | |
133 | ||
134 | for (i = 0; i < disks; i++) { | |
5dd33c9a | 135 | if (blocks[i] == NULL) { |
b2f46fd8 | 136 | BUG_ON(i > disks - 3); /* P or Q can't be zero */ |
5dd33c9a | 137 | srcs[i] = (void*)raid6_empty_zero_page; |
584acdd4 | 138 | } else { |
b2f46fd8 | 139 | srcs[i] = page_address(blocks[i]) + offset; |
584acdd4 MS |
140 | if (i < disks - 2) { |
141 | stop = i; | |
142 | if (start == -1) | |
143 | start = i; | |
144 | } | |
145 | } | |
b2f46fd8 | 146 | } |
584acdd4 MS |
147 | if (submit->flags & ASYNC_TX_PQ_XOR_DST) { |
148 | BUG_ON(!raid6_call.xor_syndrome); | |
149 | if (start >= 0) | |
150 | raid6_call.xor_syndrome(disks, start, stop, len, srcs); | |
151 | } else | |
152 | raid6_call.gen_syndrome(disks, len, srcs); | |
b2f46fd8 DW |
153 | async_tx_sync_epilog(submit); |
154 | } | |
155 | ||
156 | /** | |
157 | * async_gen_syndrome - asynchronously calculate a raid6 syndrome | |
158 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
159 | * @offset: common offset into each block (src and dest) to start transaction | |
160 | * @disks: number of blocks (including missing P or Q, see below) | |
161 | * @len: length of operation in bytes | |
162 | * @submit: submission/completion modifiers | |
163 | * | |
164 | * General note: This routine assumes a field of GF(2^8) with a | |
165 | * primitive polynomial of 0x11d and a generator of {02}. | |
166 | * | |
167 | * 'disks' note: callers can optionally omit either P or Q (but not | |
168 | * both) from the calculation by setting blocks[disks-2] or | |
169 | * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <= | |
170 | * PAGE_SIZE as a temporary buffer of this size is used in the | |
171 | * synchronous path. 'disks' always accounts for both destination | |
5676470f DW |
172 | * buffers. If any source buffers (blocks[i] where i < disks - 2) are |
173 | * set to NULL those buffers will be replaced with the raid6_zero_page | |
174 | * in the synchronous path and omitted in the hardware-asynchronous | |
175 | * path. | |
b2f46fd8 DW |
176 | */ |
177 | struct dma_async_tx_descriptor * | |
178 | async_gen_syndrome(struct page **blocks, unsigned int offset, int disks, | |
179 | size_t len, struct async_submit_ctl *submit) | |
180 | { | |
181 | int src_cnt = disks - 2; | |
182 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, | |
183 | &P(blocks, disks), 2, | |
184 | blocks, src_cnt, len); | |
185 | struct dma_device *device = chan ? chan->device : NULL; | |
7476bd79 | 186 | struct dmaengine_unmap_data *unmap = NULL; |
b2f46fd8 DW |
187 | |
188 | BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks))); | |
189 | ||
7476bd79 DW |
190 | if (device) |
191 | unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO); | |
b2f46fd8 | 192 | |
584acdd4 MS |
193 | /* XORing P/Q is only implemented in software */ |
194 | if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) && | |
b2f46fd8 | 195 | (src_cnt <= dma_maxpq(device, 0) || |
83544ae9 DW |
196 | dma_maxpq(device, DMA_PREP_CONTINUE) > 0) && |
197 | is_dma_pq_aligned(device, offset, 0, len)) { | |
7476bd79 DW |
198 | struct dma_async_tx_descriptor *tx; |
199 | enum dma_ctrl_flags dma_flags = 0; | |
200 | unsigned char coefs[src_cnt]; | |
201 | int i, j; | |
202 | ||
b2f46fd8 DW |
203 | /* run the p+q asynchronously */ |
204 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
205 | __func__, disks, len); | |
7476bd79 DW |
206 | |
207 | /* convert source addresses being careful to collapse 'empty' | |
208 | * sources and update the coefficients accordingly | |
209 | */ | |
210 | unmap->len = len; | |
211 | for (i = 0, j = 0; i < src_cnt; i++) { | |
212 | if (blocks[i] == NULL) | |
213 | continue; | |
214 | unmap->addr[j] = dma_map_page(device->dev, blocks[i], offset, | |
215 | len, DMA_TO_DEVICE); | |
216 | coefs[j] = raid6_gfexp[i]; | |
217 | unmap->to_cnt++; | |
218 | j++; | |
219 | } | |
220 | ||
221 | /* | |
222 | * DMAs use destinations as sources, | |
223 | * so use BIDIRECTIONAL mapping | |
224 | */ | |
225 | unmap->bidi_cnt++; | |
226 | if (P(blocks, disks)) | |
227 | unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks), | |
228 | offset, len, DMA_BIDIRECTIONAL); | |
229 | else { | |
230 | unmap->addr[j++] = 0; | |
231 | dma_flags |= DMA_PREP_PQ_DISABLE_P; | |
232 | } | |
233 | ||
234 | unmap->bidi_cnt++; | |
235 | if (Q(blocks, disks)) | |
236 | unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks), | |
237 | offset, len, DMA_BIDIRECTIONAL); | |
238 | else { | |
239 | unmap->addr[j++] = 0; | |
240 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; | |
241 | } | |
242 | ||
243 | tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, submit); | |
244 | dmaengine_unmap_put(unmap); | |
245 | return tx; | |
b2f46fd8 DW |
246 | } |
247 | ||
7476bd79 DW |
248 | dmaengine_unmap_put(unmap); |
249 | ||
b2f46fd8 DW |
250 | /* run the pq synchronously */ |
251 | pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len); | |
252 | ||
253 | /* wait for any prerequisite operations */ | |
254 | async_tx_quiesce(&submit->depend_tx); | |
255 | ||
256 | if (!P(blocks, disks)) { | |
030b0772 | 257 | P(blocks, disks) = pq_scribble_page; |
b2f46fd8 DW |
258 | BUG_ON(len + offset > PAGE_SIZE); |
259 | } | |
260 | if (!Q(blocks, disks)) { | |
030b0772 | 261 | Q(blocks, disks) = pq_scribble_page; |
b2f46fd8 DW |
262 | BUG_ON(len + offset > PAGE_SIZE); |
263 | } | |
264 | do_sync_gen_syndrome(blocks, offset, disks, len, submit); | |
265 | ||
266 | return NULL; | |
267 | } | |
268 | EXPORT_SYMBOL_GPL(async_gen_syndrome); | |
269 | ||
7b3cc2b1 DW |
270 | static inline struct dma_chan * |
271 | pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len) | |
272 | { | |
273 | #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA | |
274 | return NULL; | |
275 | #endif | |
276 | return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks, | |
277 | disks, len); | |
278 | } | |
279 | ||
b2f46fd8 DW |
280 | /** |
281 | * async_syndrome_val - asynchronously validate a raid6 syndrome | |
282 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
283 | * @offset: common offset into each block (src and dest) to start transaction | |
284 | * @disks: number of blocks (including missing P or Q, see below) | |
285 | * @len: length of operation in bytes | |
286 | * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set | |
287 | * @spare: temporary result buffer for the synchronous case | |
288 | * @submit: submission / completion modifiers | |
289 | * | |
290 | * The same notes from async_gen_syndrome apply to the 'blocks', | |
291 | * and 'disks' parameters of this routine. The synchronous path | |
292 | * requires a temporary result buffer and submit->scribble to be | |
293 | * specified. | |
294 | */ | |
295 | struct dma_async_tx_descriptor * | |
296 | async_syndrome_val(struct page **blocks, unsigned int offset, int disks, | |
297 | size_t len, enum sum_check_flags *pqres, struct page *spare, | |
298 | struct async_submit_ctl *submit) | |
299 | { | |
7b3cc2b1 | 300 | struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len); |
b2f46fd8 DW |
301 | struct dma_device *device = chan ? chan->device : NULL; |
302 | struct dma_async_tx_descriptor *tx; | |
b2141e69 | 303 | unsigned char coefs[disks-2]; |
b2f46fd8 | 304 | enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0; |
1786b943 | 305 | struct dmaengine_unmap_data *unmap = NULL; |
b2f46fd8 DW |
306 | |
307 | BUG_ON(disks < 4); | |
308 | ||
1786b943 DW |
309 | if (device) |
310 | unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO); | |
b2f46fd8 | 311 | |
1786b943 | 312 | if (unmap && disks <= dma_maxpq(device, 0) && |
83544ae9 | 313 | is_dma_pq_aligned(device, offset, 0, len)) { |
b2f46fd8 | 314 | struct device *dev = device->dev; |
1786b943 DW |
315 | dma_addr_t pq[2]; |
316 | int i, j = 0, src_cnt = 0; | |
b2f46fd8 DW |
317 | |
318 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
319 | __func__, disks, len); | |
1786b943 DW |
320 | |
321 | unmap->len = len; | |
322 | for (i = 0; i < disks-2; i++) | |
323 | if (likely(blocks[i])) { | |
324 | unmap->addr[j] = dma_map_page(dev, blocks[i], | |
325 | offset, len, | |
326 | DMA_TO_DEVICE); | |
327 | coefs[j] = raid6_gfexp[i]; | |
328 | unmap->to_cnt++; | |
329 | src_cnt++; | |
330 | j++; | |
331 | } | |
332 | ||
333 | if (!P(blocks, disks)) { | |
334 | pq[0] = 0; | |
b2f46fd8 | 335 | dma_flags |= DMA_PREP_PQ_DISABLE_P; |
1786b943 | 336 | } else { |
5676470f | 337 | pq[0] = dma_map_page(dev, P(blocks, disks), |
b2141e69 N |
338 | offset, len, |
339 | DMA_TO_DEVICE); | |
1786b943 DW |
340 | unmap->addr[j++] = pq[0]; |
341 | unmap->to_cnt++; | |
342 | } | |
343 | if (!Q(blocks, disks)) { | |
344 | pq[1] = 0; | |
b2f46fd8 | 345 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; |
1786b943 | 346 | } else { |
5676470f | 347 | pq[1] = dma_map_page(dev, Q(blocks, disks), |
b2141e69 N |
348 | offset, len, |
349 | DMA_TO_DEVICE); | |
1786b943 DW |
350 | unmap->addr[j++] = pq[1]; |
351 | unmap->to_cnt++; | |
352 | } | |
b2141e69 | 353 | |
0403e382 DW |
354 | if (submit->flags & ASYNC_TX_FENCE) |
355 | dma_flags |= DMA_PREP_FENCE; | |
b2f46fd8 | 356 | for (;;) { |
1786b943 DW |
357 | tx = device->device_prep_dma_pq_val(chan, pq, |
358 | unmap->addr, | |
b2141e69 N |
359 | src_cnt, |
360 | coefs, | |
b2f46fd8 DW |
361 | len, pqres, |
362 | dma_flags); | |
363 | if (likely(tx)) | |
364 | break; | |
365 | async_tx_quiesce(&submit->depend_tx); | |
366 | dma_async_issue_pending(chan); | |
367 | } | |
1786b943 DW |
368 | |
369 | dma_set_unmap(tx, unmap); | |
b2f46fd8 DW |
370 | async_tx_submit(chan, tx, submit); |
371 | ||
372 | return tx; | |
373 | } else { | |
374 | struct page *p_src = P(blocks, disks); | |
375 | struct page *q_src = Q(blocks, disks); | |
376 | enum async_tx_flags flags_orig = submit->flags; | |
377 | dma_async_tx_callback cb_fn_orig = submit->cb_fn; | |
378 | void *scribble = submit->scribble; | |
379 | void *cb_param_orig = submit->cb_param; | |
380 | void *p, *q, *s; | |
381 | ||
382 | pr_debug("%s: (sync) disks: %d len: %zu\n", | |
383 | __func__, disks, len); | |
384 | ||
385 | /* caller must provide a temporary result buffer and | |
386 | * allow the input parameters to be preserved | |
387 | */ | |
388 | BUG_ON(!spare || !scribble); | |
389 | ||
390 | /* wait for any prerequisite operations */ | |
391 | async_tx_quiesce(&submit->depend_tx); | |
392 | ||
393 | /* recompute p and/or q into the temporary buffer and then | |
394 | * check to see the result matches the current value | |
395 | */ | |
396 | tx = NULL; | |
397 | *pqres = 0; | |
398 | if (p_src) { | |
399 | init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL, | |
400 | NULL, NULL, scribble); | |
401 | tx = async_xor(spare, blocks, offset, disks-2, len, submit); | |
402 | async_tx_quiesce(&tx); | |
403 | p = page_address(p_src) + offset; | |
404 | s = page_address(spare) + offset; | |
405 | *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P; | |
406 | } | |
407 | ||
408 | if (q_src) { | |
409 | P(blocks, disks) = NULL; | |
410 | Q(blocks, disks) = spare; | |
411 | init_async_submit(submit, 0, NULL, NULL, NULL, scribble); | |
412 | tx = async_gen_syndrome(blocks, offset, disks, len, submit); | |
413 | async_tx_quiesce(&tx); | |
414 | q = page_address(q_src) + offset; | |
415 | s = page_address(spare) + offset; | |
416 | *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q; | |
417 | } | |
418 | ||
419 | /* restore P, Q and submit */ | |
420 | P(blocks, disks) = p_src; | |
421 | Q(blocks, disks) = q_src; | |
422 | ||
423 | submit->cb_fn = cb_fn_orig; | |
424 | submit->cb_param = cb_param_orig; | |
425 | submit->flags = flags_orig; | |
426 | async_tx_sync_epilog(submit); | |
427 | ||
428 | return NULL; | |
429 | } | |
430 | } | |
431 | EXPORT_SYMBOL_GPL(async_syndrome_val); | |
432 | ||
433 | static int __init async_pq_init(void) | |
434 | { | |
030b0772 | 435 | pq_scribble_page = alloc_page(GFP_KERNEL); |
b2f46fd8 | 436 | |
030b0772 | 437 | if (pq_scribble_page) |
b2f46fd8 DW |
438 | return 0; |
439 | ||
440 | pr_err("%s: failed to allocate required spare page\n", __func__); | |
441 | ||
442 | return -ENOMEM; | |
443 | } | |
444 | ||
445 | static void __exit async_pq_exit(void) | |
446 | { | |
030b0772 | 447 | put_page(pq_scribble_page); |
b2f46fd8 DW |
448 | } |
449 | ||
450 | module_init(async_pq_init); | |
451 | module_exit(async_pq_exit); | |
452 | ||
453 | MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation"); | |
454 | MODULE_LICENSE("GPL"); |