aboutsummaryrefslogtreecommitdiffstats
path: root/crypto/async_tx/async_pq.c
diff options
context:
space:
mode:
Diffstat (limited to 'crypto/async_tx/async_pq.c')
-rw-r--r--crypto/async_tx/async_pq.c395
1 files changed, 395 insertions, 0 deletions
diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
new file mode 100644
index 000000000000..b88db6d1dc65
--- /dev/null
+++ b/crypto/async_tx/async_pq.c
@@ -0,0 +1,395 @@
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 */
31static struct page *scribble;
32
33static 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 */
50static __async_inline struct dma_async_tx_descriptor *
51do_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;
104 submit->flags |= ASYNC_TX_FENCE;
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 }
115 if (submit->flags & ASYNC_TX_FENCE)
116 dma_flags |= DMA_PREP_FENCE;
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 */
150static void
151do_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 */
194struct dma_async_tx_descriptor *
195async_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 is_dma_pq_aligned(device, offset, 0, len)) {
216 /* run the p+q asynchronously */
217 pr_debug("%s: (async) disks: %d len: %zu\n",
218 __func__, disks, len);
219 return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset,
220 disks, len, dma_src, submit);
221 }
222
223 /* run the pq synchronously */
224 pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
225
226 /* wait for any prerequisite operations */
227 async_tx_quiesce(&submit->depend_tx);
228
229 if (!P(blocks, disks)) {
230 P(blocks, disks) = scribble;
231 BUG_ON(len + offset > PAGE_SIZE);
232 }
233 if (!Q(blocks, disks)) {
234 Q(blocks, disks) = scribble;
235 BUG_ON(len + offset > PAGE_SIZE);
236 }
237 do_sync_gen_syndrome(blocks, offset, disks, len, submit);
238
239 return NULL;
240}
241EXPORT_SYMBOL_GPL(async_gen_syndrome);
242
243/**
244 * async_syndrome_val - asynchronously validate a raid6 syndrome
245 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
246 * @offset: common offset into each block (src and dest) to start transaction
247 * @disks: number of blocks (including missing P or Q, see below)
248 * @len: length of operation in bytes
249 * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
250 * @spare: temporary result buffer for the synchronous case
251 * @submit: submission / completion modifiers
252 *
253 * The same notes from async_gen_syndrome apply to the 'blocks',
254 * and 'disks' parameters of this routine. The synchronous path
255 * requires a temporary result buffer and submit->scribble to be
256 * specified.
257 */
258struct dma_async_tx_descriptor *
259async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
260 size_t len, enum sum_check_flags *pqres, struct page *spare,
261 struct async_submit_ctl *submit)
262{
263 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ_VAL,
264 NULL, 0, blocks, disks,
265 len);
266 struct dma_device *device = chan ? chan->device : NULL;
267 struct dma_async_tx_descriptor *tx;
268 enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
269 dma_addr_t *dma_src = NULL;
270
271 BUG_ON(disks < 4);
272
273 if (submit->scribble)
274 dma_src = submit->scribble;
275 else if (sizeof(dma_addr_t) <= sizeof(struct page *))
276 dma_src = (dma_addr_t *) blocks;
277
278 if (dma_src && device && disks <= dma_maxpq(device, 0) &&
279 is_dma_pq_aligned(device, offset, 0, len)) {
280 struct device *dev = device->dev;
281 dma_addr_t *pq = &dma_src[disks-2];
282 int i;
283
284 pr_debug("%s: (async) disks: %d len: %zu\n",
285 __func__, disks, len);
286 if (!P(blocks, disks))
287 dma_flags |= DMA_PREP_PQ_DISABLE_P;
288 if (!Q(blocks, disks))
289 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
290 if (submit->flags & ASYNC_TX_FENCE)
291 dma_flags |= DMA_PREP_FENCE;
292 for (i = 0; i < disks; i++)
293 if (likely(blocks[i])) {
294 BUG_ON(is_raid6_zero_block(blocks[i]));
295 dma_src[i] = dma_map_page(dev, blocks[i],
296 offset, len,
297 DMA_TO_DEVICE);
298 }
299
300 for (;;) {
301 tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
302 disks - 2,
303 raid6_gfexp,
304 len, pqres,
305 dma_flags);
306 if (likely(tx))
307 break;
308 async_tx_quiesce(&submit->depend_tx);
309 dma_async_issue_pending(chan);
310 }
311 async_tx_submit(chan, tx, submit);
312
313 return tx;
314 } else {
315 struct page *p_src = P(blocks, disks);
316 struct page *q_src = Q(blocks, disks);
317 enum async_tx_flags flags_orig = submit->flags;
318 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
319 void *scribble = submit->scribble;
320 void *cb_param_orig = submit->cb_param;
321 void *p, *q, *s;
322
323 pr_debug("%s: (sync) disks: %d len: %zu\n",
324 __func__, disks, len);
325
326 /* caller must provide a temporary result buffer and
327 * allow the input parameters to be preserved
328 */
329 BUG_ON(!spare || !scribble);
330
331 /* wait for any prerequisite operations */
332 async_tx_quiesce(&submit->depend_tx);
333
334 /* recompute p and/or q into the temporary buffer and then
335 * check to see the result matches the current value
336 */
337 tx = NULL;
338 *pqres = 0;
339 if (p_src) {
340 init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
341 NULL, NULL, scribble);
342 tx = async_xor(spare, blocks, offset, disks-2, len, submit);
343 async_tx_quiesce(&tx);
344 p = page_address(p_src) + offset;
345 s = page_address(spare) + offset;
346 *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
347 }
348
349 if (q_src) {
350 P(blocks, disks) = NULL;
351 Q(blocks, disks) = spare;
352 init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
353 tx = async_gen_syndrome(blocks, offset, disks, len, submit);
354 async_tx_quiesce(&tx);
355 q = page_address(q_src) + offset;
356 s = page_address(spare) + offset;
357 *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
358 }
359
360 /* restore P, Q and submit */
361 P(blocks, disks) = p_src;
362 Q(blocks, disks) = q_src;
363
364 submit->cb_fn = cb_fn_orig;
365 submit->cb_param = cb_param_orig;
366 submit->flags = flags_orig;
367 async_tx_sync_epilog(submit);
368
369 return NULL;
370 }
371}
372EXPORT_SYMBOL_GPL(async_syndrome_val);
373
374static int __init async_pq_init(void)
375{
376 scribble = alloc_page(GFP_KERNEL);
377
378 if (scribble)
379 return 0;
380
381 pr_err("%s: failed to allocate required spare page\n", __func__);
382
383 return -ENOMEM;
384}
385
386static void __exit async_pq_exit(void)
387{
388 put_page(scribble);
389}
390
391module_init(async_pq_init);
392module_exit(async_pq_exit);
393
394MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
395MODULE_LICENSE("GPL");