Commit | Line | Data |
---|---|---|
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 * | |
49 | do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks, | |
50 | const unsigned char *scfs, unsigned int offset, int disks, | |
51 | size_t len, dma_addr_t *dma_src, | |
52 | struct async_submit_ctl *submit) | |
53 | { | |
54 | struct dma_async_tx_descriptor *tx = NULL; | |
55 | struct dma_device *dma = chan->device; | |
56 | enum dma_ctrl_flags dma_flags = 0; | |
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; | |
61 | unsigned char coefs[src_cnt]; | |
62 | unsigned short pq_src_cnt; | |
63 | dma_addr_t dma_dest[2]; | |
64 | int src_off = 0; | |
65 | int idx; | |
66 | int i; | |
67 | ||
68 | /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */ | |
69 | if (P(blocks, disks)) | |
70 | dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset, | |
71 | len, DMA_BIDIRECTIONAL); | |
72 | else | |
73 | dma_flags |= DMA_PREP_PQ_DISABLE_P; | |
74 | if (Q(blocks, disks)) | |
75 | dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset, | |
76 | len, DMA_BIDIRECTIONAL); | |
77 | else | |
78 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; | |
79 | ||
80 | /* convert source addresses being careful to collapse 'empty' | |
81 | * sources and update the coefficients accordingly | |
82 | */ | |
83 | for (i = 0, idx = 0; i < src_cnt; i++) { | |
5dd33c9a | 84 | if (blocks[i] == NULL) |
b2f46fd8 DW |
85 | continue; |
86 | dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len, | |
87 | DMA_TO_DEVICE); | |
88 | coefs[idx] = scfs[i]; | |
89 | idx++; | |
90 | } | |
91 | src_cnt = idx; | |
92 | ||
93 | while (src_cnt > 0) { | |
94 | submit->flags = flags_orig; | |
95 | pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags)); | |
96 | /* if we are submitting additional pqs, leave the chain open, | |
97 | * clear the callback parameters, and leave the destination | |
98 | * buffers mapped | |
99 | */ | |
100 | if (src_cnt > pq_src_cnt) { | |
101 | submit->flags &= ~ASYNC_TX_ACK; | |
0403e382 | 102 | submit->flags |= ASYNC_TX_FENCE; |
b2f46fd8 DW |
103 | dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP; |
104 | submit->cb_fn = NULL; | |
105 | submit->cb_param = NULL; | |
106 | } else { | |
107 | dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP; | |
108 | submit->cb_fn = cb_fn_orig; | |
109 | submit->cb_param = cb_param_orig; | |
110 | if (cb_fn_orig) | |
111 | dma_flags |= DMA_PREP_INTERRUPT; | |
112 | } | |
0403e382 DW |
113 | if (submit->flags & ASYNC_TX_FENCE) |
114 | dma_flags |= DMA_PREP_FENCE; | |
b2f46fd8 DW |
115 | |
116 | /* Since we have clobbered the src_list we are committed | |
117 | * to doing this asynchronously. Drivers force forward | |
118 | * progress in case they can not provide a descriptor | |
119 | */ | |
120 | for (;;) { | |
121 | tx = dma->device_prep_dma_pq(chan, dma_dest, | |
122 | &dma_src[src_off], | |
123 | pq_src_cnt, | |
124 | &coefs[src_off], len, | |
125 | dma_flags); | |
126 | if (likely(tx)) | |
127 | break; | |
128 | async_tx_quiesce(&submit->depend_tx); | |
129 | dma_async_issue_pending(chan); | |
130 | } | |
131 | ||
132 | async_tx_submit(chan, tx, submit); | |
133 | submit->depend_tx = tx; | |
134 | ||
135 | /* drop completed sources */ | |
136 | src_cnt -= pq_src_cnt; | |
137 | src_off += pq_src_cnt; | |
138 | ||
139 | dma_flags |= DMA_PREP_CONTINUE; | |
140 | } | |
141 | ||
142 | return tx; | |
143 | } | |
144 | ||
145 | /** | |
146 | * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome | |
147 | */ | |
148 | static void | |
149 | do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks, | |
150 | size_t len, struct async_submit_ctl *submit) | |
151 | { | |
152 | void **srcs; | |
153 | int i; | |
154 | ||
155 | if (submit->scribble) | |
156 | srcs = submit->scribble; | |
157 | else | |
158 | srcs = (void **) blocks; | |
159 | ||
160 | for (i = 0; i < disks; i++) { | |
5dd33c9a | 161 | if (blocks[i] == NULL) { |
b2f46fd8 | 162 | BUG_ON(i > disks - 3); /* P or Q can't be zero */ |
5dd33c9a | 163 | srcs[i] = (void*)raid6_empty_zero_page; |
b2f46fd8 DW |
164 | } else |
165 | srcs[i] = page_address(blocks[i]) + offset; | |
166 | } | |
167 | raid6_call.gen_syndrome(disks, len, srcs); | |
168 | async_tx_sync_epilog(submit); | |
169 | } | |
170 | ||
171 | /** | |
172 | * async_gen_syndrome - asynchronously calculate a raid6 syndrome | |
173 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
174 | * @offset: common offset into each block (src and dest) to start transaction | |
175 | * @disks: number of blocks (including missing P or Q, see below) | |
176 | * @len: length of operation in bytes | |
177 | * @submit: submission/completion modifiers | |
178 | * | |
179 | * General note: This routine assumes a field of GF(2^8) with a | |
180 | * primitive polynomial of 0x11d and a generator of {02}. | |
181 | * | |
182 | * 'disks' note: callers can optionally omit either P or Q (but not | |
183 | * both) from the calculation by setting blocks[disks-2] or | |
184 | * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <= | |
185 | * PAGE_SIZE as a temporary buffer of this size is used in the | |
186 | * synchronous path. 'disks' always accounts for both destination | |
5676470f DW |
187 | * buffers. If any source buffers (blocks[i] where i < disks - 2) are |
188 | * set to NULL those buffers will be replaced with the raid6_zero_page | |
189 | * in the synchronous path and omitted in the hardware-asynchronous | |
190 | * path. | |
b2f46fd8 DW |
191 | * |
192 | * 'blocks' note: if submit->scribble is NULL then the contents of | |
5676470f DW |
193 | * 'blocks' may be overwritten to perform address conversions |
194 | * (dma_map_page() or page_address()). | |
b2f46fd8 DW |
195 | */ |
196 | struct dma_async_tx_descriptor * | |
197 | async_gen_syndrome(struct page **blocks, unsigned int offset, int disks, | |
198 | size_t len, struct async_submit_ctl *submit) | |
199 | { | |
200 | int src_cnt = disks - 2; | |
201 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, | |
202 | &P(blocks, disks), 2, | |
203 | blocks, src_cnt, len); | |
204 | struct dma_device *device = chan ? chan->device : NULL; | |
205 | dma_addr_t *dma_src = NULL; | |
206 | ||
207 | BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks))); | |
208 | ||
209 | if (submit->scribble) | |
210 | dma_src = submit->scribble; | |
211 | else if (sizeof(dma_addr_t) <= sizeof(struct page *)) | |
212 | dma_src = (dma_addr_t *) blocks; | |
213 | ||
214 | if (dma_src && device && | |
215 | (src_cnt <= dma_maxpq(device, 0) || | |
83544ae9 DW |
216 | dma_maxpq(device, DMA_PREP_CONTINUE) > 0) && |
217 | is_dma_pq_aligned(device, offset, 0, len)) { | |
b2f46fd8 DW |
218 | /* run the p+q asynchronously */ |
219 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
220 | __func__, disks, len); | |
221 | return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset, | |
222 | disks, len, dma_src, submit); | |
223 | } | |
224 | ||
225 | /* run the pq synchronously */ | |
226 | pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len); | |
227 | ||
228 | /* wait for any prerequisite operations */ | |
229 | async_tx_quiesce(&submit->depend_tx); | |
230 | ||
231 | if (!P(blocks, disks)) { | |
030b0772 | 232 | P(blocks, disks) = pq_scribble_page; |
b2f46fd8 DW |
233 | BUG_ON(len + offset > PAGE_SIZE); |
234 | } | |
235 | if (!Q(blocks, disks)) { | |
030b0772 | 236 | Q(blocks, disks) = pq_scribble_page; |
b2f46fd8 DW |
237 | BUG_ON(len + offset > PAGE_SIZE); |
238 | } | |
239 | do_sync_gen_syndrome(blocks, offset, disks, len, submit); | |
240 | ||
241 | return NULL; | |
242 | } | |
243 | EXPORT_SYMBOL_GPL(async_gen_syndrome); | |
244 | ||
7b3cc2b1 DW |
245 | static inline struct dma_chan * |
246 | pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len) | |
247 | { | |
248 | #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA | |
249 | return NULL; | |
250 | #endif | |
251 | return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks, | |
252 | disks, len); | |
253 | } | |
254 | ||
b2f46fd8 DW |
255 | /** |
256 | * async_syndrome_val - asynchronously validate a raid6 syndrome | |
257 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
258 | * @offset: common offset into each block (src and dest) to start transaction | |
259 | * @disks: number of blocks (including missing P or Q, see below) | |
260 | * @len: length of operation in bytes | |
261 | * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set | |
262 | * @spare: temporary result buffer for the synchronous case | |
263 | * @submit: submission / completion modifiers | |
264 | * | |
265 | * The same notes from async_gen_syndrome apply to the 'blocks', | |
266 | * and 'disks' parameters of this routine. The synchronous path | |
267 | * requires a temporary result buffer and submit->scribble to be | |
268 | * specified. | |
269 | */ | |
270 | struct dma_async_tx_descriptor * | |
271 | async_syndrome_val(struct page **blocks, unsigned int offset, int disks, | |
272 | size_t len, enum sum_check_flags *pqres, struct page *spare, | |
273 | struct async_submit_ctl *submit) | |
274 | { | |
7b3cc2b1 | 275 | struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len); |
b2f46fd8 DW |
276 | struct dma_device *device = chan ? chan->device : NULL; |
277 | struct dma_async_tx_descriptor *tx; | |
b2141e69 | 278 | unsigned char coefs[disks-2]; |
b2f46fd8 DW |
279 | enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0; |
280 | dma_addr_t *dma_src = NULL; | |
b2141e69 | 281 | int src_cnt = 0; |
b2f46fd8 DW |
282 | |
283 | BUG_ON(disks < 4); | |
284 | ||
285 | if (submit->scribble) | |
286 | dma_src = submit->scribble; | |
287 | else if (sizeof(dma_addr_t) <= sizeof(struct page *)) | |
288 | dma_src = (dma_addr_t *) blocks; | |
289 | ||
83544ae9 DW |
290 | if (dma_src && device && disks <= dma_maxpq(device, 0) && |
291 | is_dma_pq_aligned(device, offset, 0, len)) { | |
b2f46fd8 DW |
292 | struct device *dev = device->dev; |
293 | dma_addr_t *pq = &dma_src[disks-2]; | |
294 | int i; | |
295 | ||
296 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
297 | __func__, disks, len); | |
298 | if (!P(blocks, disks)) | |
299 | dma_flags |= DMA_PREP_PQ_DISABLE_P; | |
b2141e69 | 300 | else |
5676470f | 301 | pq[0] = dma_map_page(dev, P(blocks, disks), |
b2141e69 N |
302 | offset, len, |
303 | DMA_TO_DEVICE); | |
b2f46fd8 DW |
304 | if (!Q(blocks, disks)) |
305 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; | |
b2141e69 | 306 | else |
5676470f | 307 | pq[1] = dma_map_page(dev, Q(blocks, disks), |
b2141e69 N |
308 | offset, len, |
309 | DMA_TO_DEVICE); | |
310 | ||
0403e382 DW |
311 | if (submit->flags & ASYNC_TX_FENCE) |
312 | dma_flags |= DMA_PREP_FENCE; | |
b2141e69 N |
313 | for (i = 0; i < disks-2; i++) |
314 | if (likely(blocks[i])) { | |
315 | dma_src[src_cnt] = dma_map_page(dev, blocks[i], | |
316 | offset, len, | |
317 | DMA_TO_DEVICE); | |
318 | coefs[src_cnt] = raid6_gfexp[i]; | |
319 | src_cnt++; | |
320 | } | |
b2f46fd8 DW |
321 | |
322 | for (;;) { | |
323 | tx = device->device_prep_dma_pq_val(chan, pq, dma_src, | |
b2141e69 N |
324 | src_cnt, |
325 | coefs, | |
b2f46fd8 DW |
326 | len, pqres, |
327 | dma_flags); | |
328 | if (likely(tx)) | |
329 | break; | |
330 | async_tx_quiesce(&submit->depend_tx); | |
331 | dma_async_issue_pending(chan); | |
332 | } | |
333 | async_tx_submit(chan, tx, submit); | |
334 | ||
335 | return tx; | |
336 | } else { | |
337 | struct page *p_src = P(blocks, disks); | |
338 | struct page *q_src = Q(blocks, disks); | |
339 | enum async_tx_flags flags_orig = submit->flags; | |
340 | dma_async_tx_callback cb_fn_orig = submit->cb_fn; | |
341 | void *scribble = submit->scribble; | |
342 | void *cb_param_orig = submit->cb_param; | |
343 | void *p, *q, *s; | |
344 | ||
345 | pr_debug("%s: (sync) disks: %d len: %zu\n", | |
346 | __func__, disks, len); | |
347 | ||
348 | /* caller must provide a temporary result buffer and | |
349 | * allow the input parameters to be preserved | |
350 | */ | |
351 | BUG_ON(!spare || !scribble); | |
352 | ||
353 | /* wait for any prerequisite operations */ | |
354 | async_tx_quiesce(&submit->depend_tx); | |
355 | ||
356 | /* recompute p and/or q into the temporary buffer and then | |
357 | * check to see the result matches the current value | |
358 | */ | |
359 | tx = NULL; | |
360 | *pqres = 0; | |
361 | if (p_src) { | |
362 | init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL, | |
363 | NULL, NULL, scribble); | |
364 | tx = async_xor(spare, blocks, offset, disks-2, len, submit); | |
365 | async_tx_quiesce(&tx); | |
366 | p = page_address(p_src) + offset; | |
367 | s = page_address(spare) + offset; | |
368 | *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P; | |
369 | } | |
370 | ||
371 | if (q_src) { | |
372 | P(blocks, disks) = NULL; | |
373 | Q(blocks, disks) = spare; | |
374 | init_async_submit(submit, 0, NULL, NULL, NULL, scribble); | |
375 | tx = async_gen_syndrome(blocks, offset, disks, len, submit); | |
376 | async_tx_quiesce(&tx); | |
377 | q = page_address(q_src) + offset; | |
378 | s = page_address(spare) + offset; | |
379 | *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q; | |
380 | } | |
381 | ||
382 | /* restore P, Q and submit */ | |
383 | P(blocks, disks) = p_src; | |
384 | Q(blocks, disks) = q_src; | |
385 | ||
386 | submit->cb_fn = cb_fn_orig; | |
387 | submit->cb_param = cb_param_orig; | |
388 | submit->flags = flags_orig; | |
389 | async_tx_sync_epilog(submit); | |
390 | ||
391 | return NULL; | |
392 | } | |
393 | } | |
394 | EXPORT_SYMBOL_GPL(async_syndrome_val); | |
395 | ||
396 | static int __init async_pq_init(void) | |
397 | { | |
030b0772 | 398 | pq_scribble_page = alloc_page(GFP_KERNEL); |
b2f46fd8 | 399 | |
030b0772 | 400 | if (pq_scribble_page) |
b2f46fd8 DW |
401 | return 0; |
402 | ||
403 | pr_err("%s: failed to allocate required spare page\n", __func__); | |
404 | ||
405 | return -ENOMEM; | |
406 | } | |
407 | ||
408 | static void __exit async_pq_exit(void) | |
409 | { | |
030b0772 | 410 | put_page(pq_scribble_page); |
b2f46fd8 DW |
411 | } |
412 | ||
413 | module_init(async_pq_init); | |
414 | module_exit(async_pq_exit); | |
415 | ||
416 | MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation"); | |
417 | MODULE_LICENSE("GPL"); |