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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; | |
127 | ||
128 | if (submit->scribble) | |
129 | srcs = submit->scribble; | |
130 | else | |
131 | srcs = (void **) blocks; | |
132 | ||
133 | for (i = 0; i < disks; i++) { | |
5dd33c9a | 134 | if (blocks[i] == NULL) { |
b2f46fd8 | 135 | BUG_ON(i > disks - 3); /* P or Q can't be zero */ |
5dd33c9a | 136 | srcs[i] = (void*)raid6_empty_zero_page; |
b2f46fd8 DW |
137 | } else |
138 | srcs[i] = page_address(blocks[i]) + offset; | |
139 | } | |
140 | raid6_call.gen_syndrome(disks, len, srcs); | |
141 | async_tx_sync_epilog(submit); | |
142 | } | |
143 | ||
144 | /** | |
145 | * async_gen_syndrome - asynchronously calculate a raid6 syndrome | |
146 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
147 | * @offset: common offset into each block (src and dest) to start transaction | |
148 | * @disks: number of blocks (including missing P or Q, see below) | |
149 | * @len: length of operation in bytes | |
150 | * @submit: submission/completion modifiers | |
151 | * | |
152 | * General note: This routine assumes a field of GF(2^8) with a | |
153 | * primitive polynomial of 0x11d and a generator of {02}. | |
154 | * | |
155 | * 'disks' note: callers can optionally omit either P or Q (but not | |
156 | * both) from the calculation by setting blocks[disks-2] or | |
157 | * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <= | |
158 | * PAGE_SIZE as a temporary buffer of this size is used in the | |
159 | * synchronous path. 'disks' always accounts for both destination | |
5676470f DW |
160 | * buffers. If any source buffers (blocks[i] where i < disks - 2) are |
161 | * set to NULL those buffers will be replaced with the raid6_zero_page | |
162 | * in the synchronous path and omitted in the hardware-asynchronous | |
163 | * path. | |
b2f46fd8 DW |
164 | */ |
165 | struct dma_async_tx_descriptor * | |
166 | async_gen_syndrome(struct page **blocks, unsigned int offset, int disks, | |
167 | size_t len, struct async_submit_ctl *submit) | |
168 | { | |
169 | int src_cnt = disks - 2; | |
170 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, | |
171 | &P(blocks, disks), 2, | |
172 | blocks, src_cnt, len); | |
173 | struct dma_device *device = chan ? chan->device : NULL; | |
7476bd79 | 174 | struct dmaengine_unmap_data *unmap = NULL; |
b2f46fd8 DW |
175 | |
176 | BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks))); | |
177 | ||
7476bd79 DW |
178 | if (device) |
179 | unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO); | |
b2f46fd8 | 180 | |
7476bd79 | 181 | if (unmap && |
b2f46fd8 | 182 | (src_cnt <= dma_maxpq(device, 0) || |
83544ae9 DW |
183 | dma_maxpq(device, DMA_PREP_CONTINUE) > 0) && |
184 | is_dma_pq_aligned(device, offset, 0, len)) { | |
7476bd79 DW |
185 | struct dma_async_tx_descriptor *tx; |
186 | enum dma_ctrl_flags dma_flags = 0; | |
187 | unsigned char coefs[src_cnt]; | |
188 | int i, j; | |
189 | ||
b2f46fd8 DW |
190 | /* run the p+q asynchronously */ |
191 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
192 | __func__, disks, len); | |
7476bd79 DW |
193 | |
194 | /* convert source addresses being careful to collapse 'empty' | |
195 | * sources and update the coefficients accordingly | |
196 | */ | |
197 | unmap->len = len; | |
198 | for (i = 0, j = 0; i < src_cnt; i++) { | |
199 | if (blocks[i] == NULL) | |
200 | continue; | |
201 | unmap->addr[j] = dma_map_page(device->dev, blocks[i], offset, | |
202 | len, DMA_TO_DEVICE); | |
203 | coefs[j] = raid6_gfexp[i]; | |
204 | unmap->to_cnt++; | |
205 | j++; | |
206 | } | |
207 | ||
208 | /* | |
209 | * DMAs use destinations as sources, | |
210 | * so use BIDIRECTIONAL mapping | |
211 | */ | |
212 | unmap->bidi_cnt++; | |
213 | if (P(blocks, disks)) | |
214 | unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks), | |
215 | offset, len, DMA_BIDIRECTIONAL); | |
216 | else { | |
217 | unmap->addr[j++] = 0; | |
218 | dma_flags |= DMA_PREP_PQ_DISABLE_P; | |
219 | } | |
220 | ||
221 | unmap->bidi_cnt++; | |
222 | if (Q(blocks, disks)) | |
223 | unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks), | |
224 | offset, len, DMA_BIDIRECTIONAL); | |
225 | else { | |
226 | unmap->addr[j++] = 0; | |
227 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; | |
228 | } | |
229 | ||
230 | tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, submit); | |
231 | dmaengine_unmap_put(unmap); | |
232 | return tx; | |
b2f46fd8 DW |
233 | } |
234 | ||
7476bd79 DW |
235 | dmaengine_unmap_put(unmap); |
236 | ||
b2f46fd8 DW |
237 | /* run the pq synchronously */ |
238 | pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len); | |
239 | ||
240 | /* wait for any prerequisite operations */ | |
241 | async_tx_quiesce(&submit->depend_tx); | |
242 | ||
243 | if (!P(blocks, disks)) { | |
030b0772 | 244 | P(blocks, disks) = pq_scribble_page; |
b2f46fd8 DW |
245 | BUG_ON(len + offset > PAGE_SIZE); |
246 | } | |
247 | if (!Q(blocks, disks)) { | |
030b0772 | 248 | Q(blocks, disks) = pq_scribble_page; |
b2f46fd8 DW |
249 | BUG_ON(len + offset > PAGE_SIZE); |
250 | } | |
251 | do_sync_gen_syndrome(blocks, offset, disks, len, submit); | |
252 | ||
253 | return NULL; | |
254 | } | |
255 | EXPORT_SYMBOL_GPL(async_gen_syndrome); | |
256 | ||
7b3cc2b1 DW |
257 | static inline struct dma_chan * |
258 | pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len) | |
259 | { | |
260 | #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA | |
261 | return NULL; | |
262 | #endif | |
263 | return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks, | |
264 | disks, len); | |
265 | } | |
266 | ||
b2f46fd8 DW |
267 | /** |
268 | * async_syndrome_val - asynchronously validate a raid6 syndrome | |
269 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
270 | * @offset: common offset into each block (src and dest) to start transaction | |
271 | * @disks: number of blocks (including missing P or Q, see below) | |
272 | * @len: length of operation in bytes | |
273 | * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set | |
274 | * @spare: temporary result buffer for the synchronous case | |
275 | * @submit: submission / completion modifiers | |
276 | * | |
277 | * The same notes from async_gen_syndrome apply to the 'blocks', | |
278 | * and 'disks' parameters of this routine. The synchronous path | |
279 | * requires a temporary result buffer and submit->scribble to be | |
280 | * specified. | |
281 | */ | |
282 | struct dma_async_tx_descriptor * | |
283 | async_syndrome_val(struct page **blocks, unsigned int offset, int disks, | |
284 | size_t len, enum sum_check_flags *pqres, struct page *spare, | |
285 | struct async_submit_ctl *submit) | |
286 | { | |
7b3cc2b1 | 287 | struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len); |
b2f46fd8 DW |
288 | struct dma_device *device = chan ? chan->device : NULL; |
289 | struct dma_async_tx_descriptor *tx; | |
b2141e69 | 290 | unsigned char coefs[disks-2]; |
b2f46fd8 | 291 | enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0; |
1786b943 | 292 | struct dmaengine_unmap_data *unmap = NULL; |
b2f46fd8 DW |
293 | |
294 | BUG_ON(disks < 4); | |
295 | ||
1786b943 DW |
296 | if (device) |
297 | unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOIO); | |
b2f46fd8 | 298 | |
1786b943 | 299 | if (unmap && disks <= dma_maxpq(device, 0) && |
83544ae9 | 300 | is_dma_pq_aligned(device, offset, 0, len)) { |
b2f46fd8 | 301 | struct device *dev = device->dev; |
1786b943 DW |
302 | dma_addr_t pq[2]; |
303 | int i, j = 0, src_cnt = 0; | |
b2f46fd8 DW |
304 | |
305 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
306 | __func__, disks, len); | |
1786b943 DW |
307 | |
308 | unmap->len = len; | |
309 | for (i = 0; i < disks-2; i++) | |
310 | if (likely(blocks[i])) { | |
311 | unmap->addr[j] = dma_map_page(dev, blocks[i], | |
312 | offset, len, | |
313 | DMA_TO_DEVICE); | |
314 | coefs[j] = raid6_gfexp[i]; | |
315 | unmap->to_cnt++; | |
316 | src_cnt++; | |
317 | j++; | |
318 | } | |
319 | ||
320 | if (!P(blocks, disks)) { | |
321 | pq[0] = 0; | |
b2f46fd8 | 322 | dma_flags |= DMA_PREP_PQ_DISABLE_P; |
1786b943 | 323 | } else { |
5676470f | 324 | pq[0] = dma_map_page(dev, P(blocks, disks), |
b2141e69 N |
325 | offset, len, |
326 | DMA_TO_DEVICE); | |
1786b943 DW |
327 | unmap->addr[j++] = pq[0]; |
328 | unmap->to_cnt++; | |
329 | } | |
330 | if (!Q(blocks, disks)) { | |
331 | pq[1] = 0; | |
b2f46fd8 | 332 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; |
1786b943 | 333 | } else { |
5676470f | 334 | pq[1] = dma_map_page(dev, Q(blocks, disks), |
b2141e69 N |
335 | offset, len, |
336 | DMA_TO_DEVICE); | |
1786b943 DW |
337 | unmap->addr[j++] = pq[1]; |
338 | unmap->to_cnt++; | |
339 | } | |
b2141e69 | 340 | |
0403e382 DW |
341 | if (submit->flags & ASYNC_TX_FENCE) |
342 | dma_flags |= DMA_PREP_FENCE; | |
b2f46fd8 | 343 | for (;;) { |
1786b943 DW |
344 | tx = device->device_prep_dma_pq_val(chan, pq, |
345 | unmap->addr, | |
b2141e69 N |
346 | src_cnt, |
347 | coefs, | |
b2f46fd8 DW |
348 | len, pqres, |
349 | dma_flags); | |
350 | if (likely(tx)) | |
351 | break; | |
352 | async_tx_quiesce(&submit->depend_tx); | |
353 | dma_async_issue_pending(chan); | |
354 | } | |
1786b943 DW |
355 | |
356 | dma_set_unmap(tx, unmap); | |
b2f46fd8 DW |
357 | async_tx_submit(chan, tx, submit); |
358 | ||
359 | return tx; | |
360 | } else { | |
361 | struct page *p_src = P(blocks, disks); | |
362 | struct page *q_src = Q(blocks, disks); | |
363 | enum async_tx_flags flags_orig = submit->flags; | |
364 | dma_async_tx_callback cb_fn_orig = submit->cb_fn; | |
365 | void *scribble = submit->scribble; | |
366 | void *cb_param_orig = submit->cb_param; | |
367 | void *p, *q, *s; | |
368 | ||
369 | pr_debug("%s: (sync) disks: %d len: %zu\n", | |
370 | __func__, disks, len); | |
371 | ||
372 | /* caller must provide a temporary result buffer and | |
373 | * allow the input parameters to be preserved | |
374 | */ | |
375 | BUG_ON(!spare || !scribble); | |
376 | ||
377 | /* wait for any prerequisite operations */ | |
378 | async_tx_quiesce(&submit->depend_tx); | |
379 | ||
380 | /* recompute p and/or q into the temporary buffer and then | |
381 | * check to see the result matches the current value | |
382 | */ | |
383 | tx = NULL; | |
384 | *pqres = 0; | |
385 | if (p_src) { | |
386 | init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL, | |
387 | NULL, NULL, scribble); | |
388 | tx = async_xor(spare, blocks, offset, disks-2, len, submit); | |
389 | async_tx_quiesce(&tx); | |
390 | p = page_address(p_src) + offset; | |
391 | s = page_address(spare) + offset; | |
392 | *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P; | |
393 | } | |
394 | ||
395 | if (q_src) { | |
396 | P(blocks, disks) = NULL; | |
397 | Q(blocks, disks) = spare; | |
398 | init_async_submit(submit, 0, NULL, NULL, NULL, scribble); | |
399 | tx = async_gen_syndrome(blocks, offset, disks, len, submit); | |
400 | async_tx_quiesce(&tx); | |
401 | q = page_address(q_src) + offset; | |
402 | s = page_address(spare) + offset; | |
403 | *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q; | |
404 | } | |
405 | ||
406 | /* restore P, Q and submit */ | |
407 | P(blocks, disks) = p_src; | |
408 | Q(blocks, disks) = q_src; | |
409 | ||
410 | submit->cb_fn = cb_fn_orig; | |
411 | submit->cb_param = cb_param_orig; | |
412 | submit->flags = flags_orig; | |
413 | async_tx_sync_epilog(submit); | |
414 | ||
415 | return NULL; | |
416 | } | |
417 | } | |
418 | EXPORT_SYMBOL_GPL(async_syndrome_val); | |
419 | ||
420 | static int __init async_pq_init(void) | |
421 | { | |
030b0772 | 422 | pq_scribble_page = alloc_page(GFP_KERNEL); |
b2f46fd8 | 423 | |
030b0772 | 424 | if (pq_scribble_page) |
b2f46fd8 DW |
425 | return 0; |
426 | ||
427 | pr_err("%s: failed to allocate required spare page\n", __func__); | |
428 | ||
429 | return -ENOMEM; | |
430 | } | |
431 | ||
432 | static void __exit async_pq_exit(void) | |
433 | { | |
030b0772 | 434 | put_page(pq_scribble_page); |
b2f46fd8 DW |
435 | } |
436 | ||
437 | module_init(async_pq_init); | |
438 | module_exit(async_pq_exit); | |
439 | ||
440 | MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation"); | |
441 | MODULE_LICENSE("GPL"); |