blob: 60476560e0b0b15bb4c83b77007c1039540ca8fa [file] [log] [blame]
Dan Williamsb2f46fd2009-07-14 12:20:36 -07001/*
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 */
31static struct page *scribble;
32
Dan Williamsb2f46fd2009-07-14 12:20:36 -070033/* the struct page *blocks[] parameter passed to async_gen_syndrome()
34 * and async_syndrome_val() contains the 'P' destination address at
35 * blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
36 *
37 * note: these are macros as they are used as lvalues
38 */
39#define P(b, d) (b[d-2])
40#define Q(b, d) (b[d-1])
41
42/**
43 * do_async_gen_syndrome - asynchronously calculate P and/or Q
44 */
45static __async_inline struct dma_async_tx_descriptor *
46do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
47 const unsigned char *scfs, unsigned int offset, int disks,
48 size_t len, dma_addr_t *dma_src,
49 struct async_submit_ctl *submit)
50{
51 struct dma_async_tx_descriptor *tx = NULL;
52 struct dma_device *dma = chan->device;
53 enum dma_ctrl_flags dma_flags = 0;
54 enum async_tx_flags flags_orig = submit->flags;
55 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
56 dma_async_tx_callback cb_param_orig = submit->cb_param;
57 int src_cnt = disks - 2;
58 unsigned char coefs[src_cnt];
59 unsigned short pq_src_cnt;
60 dma_addr_t dma_dest[2];
61 int src_off = 0;
62 int idx;
63 int i;
64
65 /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */
66 if (P(blocks, disks))
67 dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset,
68 len, DMA_BIDIRECTIONAL);
69 else
70 dma_flags |= DMA_PREP_PQ_DISABLE_P;
71 if (Q(blocks, disks))
72 dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset,
73 len, DMA_BIDIRECTIONAL);
74 else
75 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
76
77 /* convert source addresses being careful to collapse 'empty'
78 * sources and update the coefficients accordingly
79 */
80 for (i = 0, idx = 0; i < src_cnt; i++) {
NeilBrown5dd33c92009-10-16 16:40:25 +110081 if (blocks[i] == NULL)
Dan Williamsb2f46fd2009-07-14 12:20:36 -070082 continue;
83 dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len,
84 DMA_TO_DEVICE);
85 coefs[idx] = scfs[i];
86 idx++;
87 }
88 src_cnt = idx;
89
90 while (src_cnt > 0) {
91 submit->flags = flags_orig;
92 pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
93 /* if we are submitting additional pqs, leave the chain open,
94 * clear the callback parameters, and leave the destination
95 * buffers mapped
96 */
97 if (src_cnt > pq_src_cnt) {
98 submit->flags &= ~ASYNC_TX_ACK;
Dan Williams0403e382009-09-08 17:42:50 -070099 submit->flags |= ASYNC_TX_FENCE;
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700100 dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP;
101 submit->cb_fn = NULL;
102 submit->cb_param = NULL;
103 } else {
104 dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP;
105 submit->cb_fn = cb_fn_orig;
106 submit->cb_param = cb_param_orig;
107 if (cb_fn_orig)
108 dma_flags |= DMA_PREP_INTERRUPT;
109 }
Dan Williams0403e382009-09-08 17:42:50 -0700110 if (submit->flags & ASYNC_TX_FENCE)
111 dma_flags |= DMA_PREP_FENCE;
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700112
113 /* Since we have clobbered the src_list we are committed
114 * to doing this asynchronously. Drivers force forward
115 * progress in case they can not provide a descriptor
116 */
117 for (;;) {
118 tx = dma->device_prep_dma_pq(chan, dma_dest,
119 &dma_src[src_off],
120 pq_src_cnt,
121 &coefs[src_off], len,
122 dma_flags);
123 if (likely(tx))
124 break;
125 async_tx_quiesce(&submit->depend_tx);
126 dma_async_issue_pending(chan);
127 }
128
129 async_tx_submit(chan, tx, submit);
130 submit->depend_tx = tx;
131
132 /* drop completed sources */
133 src_cnt -= pq_src_cnt;
134 src_off += pq_src_cnt;
135
136 dma_flags |= DMA_PREP_CONTINUE;
137 }
138
139 return tx;
140}
141
142/**
143 * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
144 */
145static void
146do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
147 size_t len, struct async_submit_ctl *submit)
148{
149 void **srcs;
150 int i;
151
152 if (submit->scribble)
153 srcs = submit->scribble;
154 else
155 srcs = (void **) blocks;
156
157 for (i = 0; i < disks; i++) {
NeilBrown5dd33c92009-10-16 16:40:25 +1100158 if (blocks[i] == NULL) {
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700159 BUG_ON(i > disks - 3); /* P or Q can't be zero */
NeilBrown5dd33c92009-10-16 16:40:25 +1100160 srcs[i] = (void*)raid6_empty_zero_page;
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700161 } else
162 srcs[i] = page_address(blocks[i]) + offset;
163 }
164 raid6_call.gen_syndrome(disks, len, srcs);
165 async_tx_sync_epilog(submit);
166}
167
168/**
169 * async_gen_syndrome - asynchronously calculate a raid6 syndrome
170 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
171 * @offset: common offset into each block (src and dest) to start transaction
172 * @disks: number of blocks (including missing P or Q, see below)
173 * @len: length of operation in bytes
174 * @submit: submission/completion modifiers
175 *
176 * General note: This routine assumes a field of GF(2^8) with a
177 * primitive polynomial of 0x11d and a generator of {02}.
178 *
179 * 'disks' note: callers can optionally omit either P or Q (but not
180 * both) from the calculation by setting blocks[disks-2] or
181 * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <=
182 * PAGE_SIZE as a temporary buffer of this size is used in the
183 * synchronous path. 'disks' always accounts for both destination
Dan Williams56764702009-10-19 18:09:32 -0700184 * buffers. If any source buffers (blocks[i] where i < disks - 2) are
185 * set to NULL those buffers will be replaced with the raid6_zero_page
186 * in the synchronous path and omitted in the hardware-asynchronous
187 * path.
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700188 *
189 * 'blocks' note: if submit->scribble is NULL then the contents of
Dan Williams56764702009-10-19 18:09:32 -0700190 * 'blocks' may be overwritten to perform address conversions
191 * (dma_map_page() or page_address()).
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700192 */
193struct dma_async_tx_descriptor *
194async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
195 size_t len, struct async_submit_ctl *submit)
196{
197 int src_cnt = disks - 2;
198 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
199 &P(blocks, disks), 2,
200 blocks, src_cnt, len);
201 struct dma_device *device = chan ? chan->device : NULL;
202 dma_addr_t *dma_src = NULL;
203
204 BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));
205
206 if (submit->scribble)
207 dma_src = submit->scribble;
208 else if (sizeof(dma_addr_t) <= sizeof(struct page *))
209 dma_src = (dma_addr_t *) blocks;
210
211 if (dma_src && device &&
212 (src_cnt <= dma_maxpq(device, 0) ||
Dan Williams83544ae2009-09-08 17:42:53 -0700213 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
214 is_dma_pq_aligned(device, offset, 0, len)) {
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700215 /* 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}
240EXPORT_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 */
257struct dma_async_tx_descriptor *
258async_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;
NeilBrownb2141e62009-10-16 16:40:34 +1100267 unsigned char coefs[disks-2];
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700268 enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
269 dma_addr_t *dma_src = NULL;
NeilBrownb2141e62009-10-16 16:40:34 +1100270 int src_cnt = 0;
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700271
272 BUG_ON(disks < 4);
273
274 if (submit->scribble)
275 dma_src = submit->scribble;
276 else if (sizeof(dma_addr_t) <= sizeof(struct page *))
277 dma_src = (dma_addr_t *) blocks;
278
Dan Williams83544ae2009-09-08 17:42:53 -0700279 if (dma_src && device && disks <= dma_maxpq(device, 0) &&
280 is_dma_pq_aligned(device, offset, 0, len)) {
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700281 struct device *dev = device->dev;
282 dma_addr_t *pq = &dma_src[disks-2];
283 int i;
284
285 pr_debug("%s: (async) disks: %d len: %zu\n",
286 __func__, disks, len);
287 if (!P(blocks, disks))
288 dma_flags |= DMA_PREP_PQ_DISABLE_P;
NeilBrownb2141e62009-10-16 16:40:34 +1100289 else
Dan Williams56764702009-10-19 18:09:32 -0700290 pq[0] = dma_map_page(dev, P(blocks, disks),
NeilBrownb2141e62009-10-16 16:40:34 +1100291 offset, len,
292 DMA_TO_DEVICE);
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700293 if (!Q(blocks, disks))
294 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
NeilBrownb2141e62009-10-16 16:40:34 +1100295 else
Dan Williams56764702009-10-19 18:09:32 -0700296 pq[1] = dma_map_page(dev, Q(blocks, disks),
NeilBrownb2141e62009-10-16 16:40:34 +1100297 offset, len,
298 DMA_TO_DEVICE);
299
Dan Williams0403e382009-09-08 17:42:50 -0700300 if (submit->flags & ASYNC_TX_FENCE)
301 dma_flags |= DMA_PREP_FENCE;
NeilBrownb2141e62009-10-16 16:40:34 +1100302 for (i = 0; i < disks-2; i++)
303 if (likely(blocks[i])) {
304 dma_src[src_cnt] = dma_map_page(dev, blocks[i],
305 offset, len,
306 DMA_TO_DEVICE);
307 coefs[src_cnt] = raid6_gfexp[i];
308 src_cnt++;
309 }
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700310
311 for (;;) {
312 tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
NeilBrownb2141e62009-10-16 16:40:34 +1100313 src_cnt,
314 coefs,
Dan Williamsb2f46fd2009-07-14 12:20:36 -0700315 len, pqres,
316 dma_flags);
317 if (likely(tx))
318 break;
319 async_tx_quiesce(&submit->depend_tx);
320 dma_async_issue_pending(chan);
321 }
322 async_tx_submit(chan, tx, submit);
323
324 return tx;
325 } else {
326 struct page *p_src = P(blocks, disks);
327 struct page *q_src = Q(blocks, disks);
328 enum async_tx_flags flags_orig = submit->flags;
329 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
330 void *scribble = submit->scribble;
331 void *cb_param_orig = submit->cb_param;
332 void *p, *q, *s;
333
334 pr_debug("%s: (sync) disks: %d len: %zu\n",
335 __func__, disks, len);
336
337 /* caller must provide a temporary result buffer and
338 * allow the input parameters to be preserved
339 */
340 BUG_ON(!spare || !scribble);
341
342 /* wait for any prerequisite operations */
343 async_tx_quiesce(&submit->depend_tx);
344
345 /* recompute p and/or q into the temporary buffer and then
346 * check to see the result matches the current value
347 */
348 tx = NULL;
349 *pqres = 0;
350 if (p_src) {
351 init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
352 NULL, NULL, scribble);
353 tx = async_xor(spare, blocks, offset, disks-2, len, submit);
354 async_tx_quiesce(&tx);
355 p = page_address(p_src) + offset;
356 s = page_address(spare) + offset;
357 *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
358 }
359
360 if (q_src) {
361 P(blocks, disks) = NULL;
362 Q(blocks, disks) = spare;
363 init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
364 tx = async_gen_syndrome(blocks, offset, disks, len, submit);
365 async_tx_quiesce(&tx);
366 q = page_address(q_src) + offset;
367 s = page_address(spare) + offset;
368 *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
369 }
370
371 /* restore P, Q and submit */
372 P(blocks, disks) = p_src;
373 Q(blocks, disks) = q_src;
374
375 submit->cb_fn = cb_fn_orig;
376 submit->cb_param = cb_param_orig;
377 submit->flags = flags_orig;
378 async_tx_sync_epilog(submit);
379
380 return NULL;
381 }
382}
383EXPORT_SYMBOL_GPL(async_syndrome_val);
384
385static int __init async_pq_init(void)
386{
387 scribble = alloc_page(GFP_KERNEL);
388
389 if (scribble)
390 return 0;
391
392 pr_err("%s: failed to allocate required spare page\n", __func__);
393
394 return -ENOMEM;
395}
396
397static void __exit async_pq_exit(void)
398{
399 put_page(scribble);
400}
401
402module_init(async_pq_init);
403module_exit(async_pq_exit);
404
405MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
406MODULE_LICENSE("GPL");