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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> | |
24 | #include <linux/dma-mapping.h> | |
25 | #include <linux/raid/pq.h> | |
26 | #include <linux/async_tx.h> | |
27 | ||
28 | /** | |
29 | * scribble - space to hold throwaway P buffer for synchronous gen_syndrome | |
30 | */ | |
31 | static struct page *scribble; | |
32 | ||
33 | static bool is_raid6_zero_block(struct page *p) | |
34 | { | |
35 | return p == (void *) raid6_empty_zero_page; | |
36 | } | |
37 | ||
38 | /* the struct page *blocks[] parameter passed to async_gen_syndrome() | |
39 | * and async_syndrome_val() contains the 'P' destination address at | |
40 | * blocks[disks-2] and the 'Q' destination address at blocks[disks-1] | |
41 | * | |
42 | * note: these are macros as they are used as lvalues | |
43 | */ | |
44 | #define P(b, d) (b[d-2]) | |
45 | #define Q(b, d) (b[d-1]) | |
46 | ||
47 | /** | |
48 | * do_async_gen_syndrome - asynchronously calculate P and/or Q | |
49 | */ | |
50 | static __async_inline struct dma_async_tx_descriptor * | |
51 | do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks, | |
52 | const unsigned char *scfs, unsigned int offset, int disks, | |
53 | size_t len, dma_addr_t *dma_src, | |
54 | struct async_submit_ctl *submit) | |
55 | { | |
56 | struct dma_async_tx_descriptor *tx = NULL; | |
57 | struct dma_device *dma = chan->device; | |
58 | enum dma_ctrl_flags dma_flags = 0; | |
59 | enum async_tx_flags flags_orig = submit->flags; | |
60 | dma_async_tx_callback cb_fn_orig = submit->cb_fn; | |
61 | dma_async_tx_callback cb_param_orig = submit->cb_param; | |
62 | int src_cnt = disks - 2; | |
63 | unsigned char coefs[src_cnt]; | |
64 | unsigned short pq_src_cnt; | |
65 | dma_addr_t dma_dest[2]; | |
66 | int src_off = 0; | |
67 | int idx; | |
68 | int i; | |
69 | ||
70 | /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */ | |
71 | if (P(blocks, disks)) | |
72 | dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset, | |
73 | len, DMA_BIDIRECTIONAL); | |
74 | else | |
75 | dma_flags |= DMA_PREP_PQ_DISABLE_P; | |
76 | if (Q(blocks, disks)) | |
77 | dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset, | |
78 | len, DMA_BIDIRECTIONAL); | |
79 | else | |
80 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; | |
81 | ||
82 | /* convert source addresses being careful to collapse 'empty' | |
83 | * sources and update the coefficients accordingly | |
84 | */ | |
85 | for (i = 0, idx = 0; i < src_cnt; i++) { | |
86 | if (is_raid6_zero_block(blocks[i])) | |
87 | continue; | |
88 | dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len, | |
89 | DMA_TO_DEVICE); | |
90 | coefs[idx] = scfs[i]; | |
91 | idx++; | |
92 | } | |
93 | src_cnt = idx; | |
94 | ||
95 | while (src_cnt > 0) { | |
96 | submit->flags = flags_orig; | |
97 | pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags)); | |
98 | /* if we are submitting additional pqs, leave the chain open, | |
99 | * clear the callback parameters, and leave the destination | |
100 | * buffers mapped | |
101 | */ | |
102 | if (src_cnt > pq_src_cnt) { | |
103 | submit->flags &= ~ASYNC_TX_ACK; | |
0403e382 | 104 | submit->flags |= ASYNC_TX_FENCE; |
b2f46fd8 DW |
105 | dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP; |
106 | submit->cb_fn = NULL; | |
107 | submit->cb_param = NULL; | |
108 | } else { | |
109 | dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP; | |
110 | submit->cb_fn = cb_fn_orig; | |
111 | submit->cb_param = cb_param_orig; | |
112 | if (cb_fn_orig) | |
113 | dma_flags |= DMA_PREP_INTERRUPT; | |
114 | } | |
0403e382 DW |
115 | if (submit->flags & ASYNC_TX_FENCE) |
116 | dma_flags |= DMA_PREP_FENCE; | |
b2f46fd8 DW |
117 | |
118 | /* Since we have clobbered the src_list we are committed | |
119 | * to doing this asynchronously. Drivers force forward | |
120 | * progress in case they can not provide a descriptor | |
121 | */ | |
122 | for (;;) { | |
123 | tx = dma->device_prep_dma_pq(chan, dma_dest, | |
124 | &dma_src[src_off], | |
125 | pq_src_cnt, | |
126 | &coefs[src_off], len, | |
127 | dma_flags); | |
128 | if (likely(tx)) | |
129 | break; | |
130 | async_tx_quiesce(&submit->depend_tx); | |
131 | dma_async_issue_pending(chan); | |
132 | } | |
133 | ||
134 | async_tx_submit(chan, tx, submit); | |
135 | submit->depend_tx = tx; | |
136 | ||
137 | /* drop completed sources */ | |
138 | src_cnt -= pq_src_cnt; | |
139 | src_off += pq_src_cnt; | |
140 | ||
141 | dma_flags |= DMA_PREP_CONTINUE; | |
142 | } | |
143 | ||
144 | return tx; | |
145 | } | |
146 | ||
147 | /** | |
148 | * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome | |
149 | */ | |
150 | static void | |
151 | do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks, | |
152 | size_t len, struct async_submit_ctl *submit) | |
153 | { | |
154 | void **srcs; | |
155 | int i; | |
156 | ||
157 | if (submit->scribble) | |
158 | srcs = submit->scribble; | |
159 | else | |
160 | srcs = (void **) blocks; | |
161 | ||
162 | for (i = 0; i < disks; i++) { | |
163 | if (is_raid6_zero_block(blocks[i])) { | |
164 | BUG_ON(i > disks - 3); /* P or Q can't be zero */ | |
165 | srcs[i] = blocks[i]; | |
166 | } else | |
167 | srcs[i] = page_address(blocks[i]) + offset; | |
168 | } | |
169 | raid6_call.gen_syndrome(disks, len, srcs); | |
170 | async_tx_sync_epilog(submit); | |
171 | } | |
172 | ||
173 | /** | |
174 | * async_gen_syndrome - asynchronously calculate a raid6 syndrome | |
175 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
176 | * @offset: common offset into each block (src and dest) to start transaction | |
177 | * @disks: number of blocks (including missing P or Q, see below) | |
178 | * @len: length of operation in bytes | |
179 | * @submit: submission/completion modifiers | |
180 | * | |
181 | * General note: This routine assumes a field of GF(2^8) with a | |
182 | * primitive polynomial of 0x11d and a generator of {02}. | |
183 | * | |
184 | * 'disks' note: callers can optionally omit either P or Q (but not | |
185 | * both) from the calculation by setting blocks[disks-2] or | |
186 | * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <= | |
187 | * PAGE_SIZE as a temporary buffer of this size is used in the | |
188 | * synchronous path. 'disks' always accounts for both destination | |
189 | * buffers. | |
190 | * | |
191 | * 'blocks' note: if submit->scribble is NULL then the contents of | |
192 | * 'blocks' may be overridden | |
193 | */ | |
194 | struct dma_async_tx_descriptor * | |
195 | async_gen_syndrome(struct page **blocks, unsigned int offset, int disks, | |
196 | size_t len, struct async_submit_ctl *submit) | |
197 | { | |
198 | int src_cnt = disks - 2; | |
199 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, | |
200 | &P(blocks, disks), 2, | |
201 | blocks, src_cnt, len); | |
202 | struct dma_device *device = chan ? chan->device : NULL; | |
203 | dma_addr_t *dma_src = NULL; | |
204 | ||
205 | BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks))); | |
206 | ||
207 | if (submit->scribble) | |
208 | dma_src = submit->scribble; | |
209 | else if (sizeof(dma_addr_t) <= sizeof(struct page *)) | |
210 | dma_src = (dma_addr_t *) blocks; | |
211 | ||
212 | if (dma_src && device && | |
213 | (src_cnt <= dma_maxpq(device, 0) || | |
214 | dma_maxpq(device, DMA_PREP_CONTINUE) > 0)) { | |
215 | /* run the p+q asynchronously */ | |
216 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
217 | __func__, disks, len); | |
218 | return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset, | |
219 | disks, len, dma_src, submit); | |
220 | } | |
221 | ||
222 | /* run the pq synchronously */ | |
223 | pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len); | |
224 | ||
225 | /* wait for any prerequisite operations */ | |
226 | async_tx_quiesce(&submit->depend_tx); | |
227 | ||
228 | if (!P(blocks, disks)) { | |
229 | P(blocks, disks) = scribble; | |
230 | BUG_ON(len + offset > PAGE_SIZE); | |
231 | } | |
232 | if (!Q(blocks, disks)) { | |
233 | Q(blocks, disks) = scribble; | |
234 | BUG_ON(len + offset > PAGE_SIZE); | |
235 | } | |
236 | do_sync_gen_syndrome(blocks, offset, disks, len, submit); | |
237 | ||
238 | return NULL; | |
239 | } | |
240 | EXPORT_SYMBOL_GPL(async_gen_syndrome); | |
241 | ||
242 | /** | |
243 | * async_syndrome_val - asynchronously validate a raid6 syndrome | |
244 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 | |
245 | * @offset: common offset into each block (src and dest) to start transaction | |
246 | * @disks: number of blocks (including missing P or Q, see below) | |
247 | * @len: length of operation in bytes | |
248 | * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set | |
249 | * @spare: temporary result buffer for the synchronous case | |
250 | * @submit: submission / completion modifiers | |
251 | * | |
252 | * The same notes from async_gen_syndrome apply to the 'blocks', | |
253 | * and 'disks' parameters of this routine. The synchronous path | |
254 | * requires a temporary result buffer and submit->scribble to be | |
255 | * specified. | |
256 | */ | |
257 | struct dma_async_tx_descriptor * | |
258 | async_syndrome_val(struct page **blocks, unsigned int offset, int disks, | |
259 | size_t len, enum sum_check_flags *pqres, struct page *spare, | |
260 | struct async_submit_ctl *submit) | |
261 | { | |
262 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ_VAL, | |
263 | NULL, 0, blocks, disks, | |
264 | len); | |
265 | struct dma_device *device = chan ? chan->device : NULL; | |
266 | struct dma_async_tx_descriptor *tx; | |
267 | enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0; | |
268 | dma_addr_t *dma_src = NULL; | |
269 | ||
270 | BUG_ON(disks < 4); | |
271 | ||
272 | if (submit->scribble) | |
273 | dma_src = submit->scribble; | |
274 | else if (sizeof(dma_addr_t) <= sizeof(struct page *)) | |
275 | dma_src = (dma_addr_t *) blocks; | |
276 | ||
277 | if (dma_src && device && disks <= dma_maxpq(device, 0)) { | |
278 | struct device *dev = device->dev; | |
279 | dma_addr_t *pq = &dma_src[disks-2]; | |
280 | int i; | |
281 | ||
282 | pr_debug("%s: (async) disks: %d len: %zu\n", | |
283 | __func__, disks, len); | |
284 | if (!P(blocks, disks)) | |
285 | dma_flags |= DMA_PREP_PQ_DISABLE_P; | |
286 | if (!Q(blocks, disks)) | |
287 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; | |
0403e382 DW |
288 | if (submit->flags & ASYNC_TX_FENCE) |
289 | dma_flags |= DMA_PREP_FENCE; | |
b2f46fd8 DW |
290 | for (i = 0; i < disks; i++) |
291 | if (likely(blocks[i])) { | |
292 | BUG_ON(is_raid6_zero_block(blocks[i])); | |
293 | dma_src[i] = dma_map_page(dev, blocks[i], | |
294 | offset, len, | |
295 | DMA_TO_DEVICE); | |
296 | } | |
297 | ||
298 | for (;;) { | |
299 | tx = device->device_prep_dma_pq_val(chan, pq, dma_src, | |
300 | disks - 2, | |
301 | raid6_gfexp, | |
302 | len, pqres, | |
303 | dma_flags); | |
304 | if (likely(tx)) | |
305 | break; | |
306 | async_tx_quiesce(&submit->depend_tx); | |
307 | dma_async_issue_pending(chan); | |
308 | } | |
309 | async_tx_submit(chan, tx, submit); | |
310 | ||
311 | return tx; | |
312 | } else { | |
313 | struct page *p_src = P(blocks, disks); | |
314 | struct page *q_src = Q(blocks, disks); | |
315 | enum async_tx_flags flags_orig = submit->flags; | |
316 | dma_async_tx_callback cb_fn_orig = submit->cb_fn; | |
317 | void *scribble = submit->scribble; | |
318 | void *cb_param_orig = submit->cb_param; | |
319 | void *p, *q, *s; | |
320 | ||
321 | pr_debug("%s: (sync) disks: %d len: %zu\n", | |
322 | __func__, disks, len); | |
323 | ||
324 | /* caller must provide a temporary result buffer and | |
325 | * allow the input parameters to be preserved | |
326 | */ | |
327 | BUG_ON(!spare || !scribble); | |
328 | ||
329 | /* wait for any prerequisite operations */ | |
330 | async_tx_quiesce(&submit->depend_tx); | |
331 | ||
332 | /* recompute p and/or q into the temporary buffer and then | |
333 | * check to see the result matches the current value | |
334 | */ | |
335 | tx = NULL; | |
336 | *pqres = 0; | |
337 | if (p_src) { | |
338 | init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL, | |
339 | NULL, NULL, scribble); | |
340 | tx = async_xor(spare, blocks, offset, disks-2, len, submit); | |
341 | async_tx_quiesce(&tx); | |
342 | p = page_address(p_src) + offset; | |
343 | s = page_address(spare) + offset; | |
344 | *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P; | |
345 | } | |
346 | ||
347 | if (q_src) { | |
348 | P(blocks, disks) = NULL; | |
349 | Q(blocks, disks) = spare; | |
350 | init_async_submit(submit, 0, NULL, NULL, NULL, scribble); | |
351 | tx = async_gen_syndrome(blocks, offset, disks, len, submit); | |
352 | async_tx_quiesce(&tx); | |
353 | q = page_address(q_src) + offset; | |
354 | s = page_address(spare) + offset; | |
355 | *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q; | |
356 | } | |
357 | ||
358 | /* restore P, Q and submit */ | |
359 | P(blocks, disks) = p_src; | |
360 | Q(blocks, disks) = q_src; | |
361 | ||
362 | submit->cb_fn = cb_fn_orig; | |
363 | submit->cb_param = cb_param_orig; | |
364 | submit->flags = flags_orig; | |
365 | async_tx_sync_epilog(submit); | |
366 | ||
367 | return NULL; | |
368 | } | |
369 | } | |
370 | EXPORT_SYMBOL_GPL(async_syndrome_val); | |
371 | ||
372 | static int __init async_pq_init(void) | |
373 | { | |
374 | scribble = alloc_page(GFP_KERNEL); | |
375 | ||
376 | if (scribble) | |
377 | return 0; | |
378 | ||
379 | pr_err("%s: failed to allocate required spare page\n", __func__); | |
380 | ||
381 | return -ENOMEM; | |
382 | } | |
383 | ||
384 | static void __exit async_pq_exit(void) | |
385 | { | |
386 | put_page(scribble); | |
387 | } | |
388 | ||
389 | module_init(async_pq_init); | |
390 | module_exit(async_pq_exit); | |
391 | ||
392 | MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation"); | |
393 | MODULE_LICENSE("GPL"); |