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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com>
4 * Copyright(c) 2009 Intel Corporation
5 */
6#include <linux/kernel.h>
7#include <linux/interrupt.h>
8#include <linux/module.h>
9#include <linux/dma-mapping.h>
10#include <linux/raid/pq.h>
11#include <linux/async_tx.h>
12#include <linux/gfp.h>
13
14/**
15 * pq_scribble_page - space to hold throwaway P or Q buffer for
16 * synchronous gen_syndrome
17 */
18static struct page *pq_scribble_page;
19
20/* the struct page *blocks[] parameter passed to async_gen_syndrome()
21 * and async_syndrome_val() contains the 'P' destination address at
22 * blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
23 *
24 * note: these are macros as they are used as lvalues
25 */
26#define P(b, d) (b[d-2])
27#define Q(b, d) (b[d-1])
28
29#define MAX_DISKS 255
30
31/**
32 * do_async_gen_syndrome - asynchronously calculate P and/or Q
33 */
34static __async_inline struct dma_async_tx_descriptor *
35do_async_gen_syndrome(struct dma_chan *chan,
36 const unsigned char *scfs, int disks,
37 struct dmaengine_unmap_data *unmap,
38 enum dma_ctrl_flags dma_flags,
39 struct async_submit_ctl *submit)
40{
41 struct dma_async_tx_descriptor *tx = NULL;
42 struct dma_device *dma = chan->device;
43 enum async_tx_flags flags_orig = submit->flags;
44 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
45 dma_async_tx_callback cb_param_orig = submit->cb_param;
46 int src_cnt = disks - 2;
47 unsigned short pq_src_cnt;
48 dma_addr_t dma_dest[2];
49 int src_off = 0;
50
51 while (src_cnt > 0) {
52 submit->flags = flags_orig;
53 pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
54 /* if we are submitting additional pqs, leave the chain open,
55 * clear the callback parameters, and leave the destination
56 * buffers mapped
57 */
58 if (src_cnt > pq_src_cnt) {
59 submit->flags &= ~ASYNC_TX_ACK;
60 submit->flags |= ASYNC_TX_FENCE;
61 submit->cb_fn = NULL;
62 submit->cb_param = NULL;
63 } else {
64 submit->cb_fn = cb_fn_orig;
65 submit->cb_param = cb_param_orig;
66 if (cb_fn_orig)
67 dma_flags |= DMA_PREP_INTERRUPT;
68 }
69 if (submit->flags & ASYNC_TX_FENCE)
70 dma_flags |= DMA_PREP_FENCE;
71
72 /* Drivers force forward progress in case they can not provide
73 * a descriptor
74 */
75 for (;;) {
76 dma_dest[0] = unmap->addr[disks - 2];
77 dma_dest[1] = unmap->addr[disks - 1];
78 tx = dma->device_prep_dma_pq(chan, dma_dest,
79 &unmap->addr[src_off],
80 pq_src_cnt,
81 &scfs[src_off], unmap->len,
82 dma_flags);
83 if (likely(tx))
84 break;
85 async_tx_quiesce(&submit->depend_tx);
86 dma_async_issue_pending(chan);
87 }
88
89 dma_set_unmap(tx, unmap);
90 async_tx_submit(chan, tx, submit);
91 submit->depend_tx = tx;
92
93 /* drop completed sources */
94 src_cnt -= pq_src_cnt;
95 src_off += pq_src_cnt;
96
97 dma_flags |= DMA_PREP_CONTINUE;
98 }
99
100 return tx;
101}
102
103/**
104 * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
105 */
106static void
107do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
108 size_t len, struct async_submit_ctl *submit)
109{
110 void **srcs;
111 int i;
112 int start = -1, stop = disks - 3;
113
114 if (submit->scribble)
115 srcs = submit->scribble;
116 else
117 srcs = (void **) blocks;
118
119 for (i = 0; i < disks; i++) {
120 if (blocks[i] == NULL) {
121 BUG_ON(i > disks - 3); /* P or Q can't be zero */
122 srcs[i] = (void*)raid6_empty_zero_page;
123 } else {
124 srcs[i] = page_address(blocks[i]) + offset;
125 if (i < disks - 2) {
126 stop = i;
127 if (start == -1)
128 start = i;
129 }
130 }
131 }
132 if (submit->flags & ASYNC_TX_PQ_XOR_DST) {
133 BUG_ON(!raid6_call.xor_syndrome);
134 if (start >= 0)
135 raid6_call.xor_syndrome(disks, start, stop, len, srcs);
136 } else
137 raid6_call.gen_syndrome(disks, len, srcs);
138 async_tx_sync_epilog(submit);
139}
140
141/**
142 * async_gen_syndrome - asynchronously calculate a raid6 syndrome
143 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
144 * @offset: common offset into each block (src and dest) to start transaction
145 * @disks: number of blocks (including missing P or Q, see below)
146 * @len: length of operation in bytes
147 * @submit: submission/completion modifiers
148 *
149 * General note: This routine assumes a field of GF(2^8) with a
150 * primitive polynomial of 0x11d and a generator of {02}.
151 *
152 * 'disks' note: callers can optionally omit either P or Q (but not
153 * both) from the calculation by setting blocks[disks-2] or
154 * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <=
155 * PAGE_SIZE as a temporary buffer of this size is used in the
156 * synchronous path. 'disks' always accounts for both destination
157 * buffers. If any source buffers (blocks[i] where i < disks - 2) are
158 * set to NULL those buffers will be replaced with the raid6_zero_page
159 * in the synchronous path and omitted in the hardware-asynchronous
160 * path.
161 */
162struct dma_async_tx_descriptor *
163async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
164 size_t len, struct async_submit_ctl *submit)
165{
166 int src_cnt = disks - 2;
167 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
168 &P(blocks, disks), 2,
169 blocks, src_cnt, len);
170 struct dma_device *device = chan ? chan->device : NULL;
171 struct dmaengine_unmap_data *unmap = NULL;
172
173 BUG_ON(disks > MAX_DISKS || !(P(blocks, disks) || Q(blocks, disks)));
174
175 if (device)
176 unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
177
178 /* XORing P/Q is only implemented in software */
179 if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) &&
180 (src_cnt <= dma_maxpq(device, 0) ||
181 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
182 is_dma_pq_aligned(device, offset, 0, len)) {
183 struct dma_async_tx_descriptor *tx;
184 enum dma_ctrl_flags dma_flags = 0;
185 unsigned char coefs[MAX_DISKS];
186 int i, j;
187
188 /* run the p+q asynchronously */
189 pr_debug("%s: (async) disks: %d len: %zu\n",
190 __func__, disks, len);
191
192 /* convert source addresses being careful to collapse 'empty'
193 * sources and update the coefficients accordingly
194 */
195 unmap->len = len;
196 for (i = 0, j = 0; i < src_cnt; i++) {
197 if (blocks[i] == NULL)
198 continue;
199 unmap->addr[j] = dma_map_page(device->dev, blocks[i], offset,
200 len, DMA_TO_DEVICE);
201 coefs[j] = raid6_gfexp[i];
202 unmap->to_cnt++;
203 j++;
204 }
205
206 /*
207 * DMAs use destinations as sources,
208 * so use BIDIRECTIONAL mapping
209 */
210 unmap->bidi_cnt++;
211 if (P(blocks, disks))
212 unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks),
213 offset, len, DMA_BIDIRECTIONAL);
214 else {
215 unmap->addr[j++] = 0;
216 dma_flags |= DMA_PREP_PQ_DISABLE_P;
217 }
218
219 unmap->bidi_cnt++;
220 if (Q(blocks, disks))
221 unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks),
222 offset, len, DMA_BIDIRECTIONAL);
223 else {
224 unmap->addr[j++] = 0;
225 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
226 }
227
228 tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, submit);
229 dmaengine_unmap_put(unmap);
230 return tx;
231 }
232
233 dmaengine_unmap_put(unmap);
234
235 /* run the pq synchronously */
236 pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
237
238 /* wait for any prerequisite operations */
239 async_tx_quiesce(&submit->depend_tx);
240
241 if (!P(blocks, disks)) {
242 P(blocks, disks) = pq_scribble_page;
243 BUG_ON(len + offset > PAGE_SIZE);
244 }
245 if (!Q(blocks, disks)) {
246 Q(blocks, disks) = pq_scribble_page;
247 BUG_ON(len + offset > PAGE_SIZE);
248 }
249 do_sync_gen_syndrome(blocks, offset, disks, len, submit);
250
251 return NULL;
252}
253EXPORT_SYMBOL_GPL(async_gen_syndrome);
254
255static inline struct dma_chan *
256pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len)
257{
258 #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
259 return NULL;
260 #endif
261 return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks,
262 disks, len);
263}
264
265/**
266 * async_syndrome_val - asynchronously validate a raid6 syndrome
267 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
268 * @offset: common offset into each block (src and dest) to start transaction
269 * @disks: number of blocks (including missing P or Q, see below)
270 * @len: length of operation in bytes
271 * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
272 * @spare: temporary result buffer for the synchronous case
273 * @submit: submission / completion modifiers
274 *
275 * The same notes from async_gen_syndrome apply to the 'blocks',
276 * and 'disks' parameters of this routine. The synchronous path
277 * requires a temporary result buffer and submit->scribble to be
278 * specified.
279 */
280struct dma_async_tx_descriptor *
281async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
282 size_t len, enum sum_check_flags *pqres, struct page *spare,
283 struct async_submit_ctl *submit)
284{
285 struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
286 struct dma_device *device = chan ? chan->device : NULL;
287 struct dma_async_tx_descriptor *tx;
288 unsigned char coefs[MAX_DISKS];
289 enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
290 struct dmaengine_unmap_data *unmap = NULL;
291
292 BUG_ON(disks < 4 || disks > MAX_DISKS);
293
294 if (device)
295 unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
296
297 if (unmap && disks <= dma_maxpq(device, 0) &&
298 is_dma_pq_aligned(device, offset, 0, len)) {
299 struct device *dev = device->dev;
300 dma_addr_t pq[2];
301 int i, j = 0, src_cnt = 0;
302
303 pr_debug("%s: (async) disks: %d len: %zu\n",
304 __func__, disks, len);
305
306 unmap->len = len;
307 for (i = 0; i < disks-2; i++)
308 if (likely(blocks[i])) {
309 unmap->addr[j] = dma_map_page(dev, blocks[i],
310 offset, len,
311 DMA_TO_DEVICE);
312 coefs[j] = raid6_gfexp[i];
313 unmap->to_cnt++;
314 src_cnt++;
315 j++;
316 }
317
318 if (!P(blocks, disks)) {
319 pq[0] = 0;
320 dma_flags |= DMA_PREP_PQ_DISABLE_P;
321 } else {
322 pq[0] = dma_map_page(dev, P(blocks, disks),
323 offset, len,
324 DMA_TO_DEVICE);
325 unmap->addr[j++] = pq[0];
326 unmap->to_cnt++;
327 }
328 if (!Q(blocks, disks)) {
329 pq[1] = 0;
330 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
331 } else {
332 pq[1] = dma_map_page(dev, Q(blocks, disks),
333 offset, len,
334 DMA_TO_DEVICE);
335 unmap->addr[j++] = pq[1];
336 unmap->to_cnt++;
337 }
338
339 if (submit->flags & ASYNC_TX_FENCE)
340 dma_flags |= DMA_PREP_FENCE;
341 for (;;) {
342 tx = device->device_prep_dma_pq_val(chan, pq,
343 unmap->addr,
344 src_cnt,
345 coefs,
346 len, pqres,
347 dma_flags);
348 if (likely(tx))
349 break;
350 async_tx_quiesce(&submit->depend_tx);
351 dma_async_issue_pending(chan);
352 }
353
354 dma_set_unmap(tx, unmap);
355 async_tx_submit(chan, tx, submit);
356 } else {
357 struct page *p_src = P(blocks, disks);
358 struct page *q_src = Q(blocks, disks);
359 enum async_tx_flags flags_orig = submit->flags;
360 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
361 void *scribble = submit->scribble;
362 void *cb_param_orig = submit->cb_param;
363 void *p, *q, *s;
364
365 pr_debug("%s: (sync) disks: %d len: %zu\n",
366 __func__, disks, len);
367
368 /* caller must provide a temporary result buffer and
369 * allow the input parameters to be preserved
370 */
371 BUG_ON(!spare || !scribble);
372
373 /* wait for any prerequisite operations */
374 async_tx_quiesce(&submit->depend_tx);
375
376 /* recompute p and/or q into the temporary buffer and then
377 * check to see the result matches the current value
378 */
379 tx = NULL;
380 *pqres = 0;
381 if (p_src) {
382 init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
383 NULL, NULL, scribble);
384 tx = async_xor(spare, blocks, offset, disks-2, len, submit);
385 async_tx_quiesce(&tx);
386 p = page_address(p_src) + offset;
387 s = page_address(spare) + offset;
388 *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
389 }
390
391 if (q_src) {
392 P(blocks, disks) = NULL;
393 Q(blocks, disks) = spare;
394 init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
395 tx = async_gen_syndrome(blocks, offset, disks, len, submit);
396 async_tx_quiesce(&tx);
397 q = page_address(q_src) + offset;
398 s = page_address(spare) + offset;
399 *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
400 }
401
402 /* restore P, Q and submit */
403 P(blocks, disks) = p_src;
404 Q(blocks, disks) = q_src;
405
406 submit->cb_fn = cb_fn_orig;
407 submit->cb_param = cb_param_orig;
408 submit->flags = flags_orig;
409 async_tx_sync_epilog(submit);
410 tx = NULL;
411 }
412 dmaengine_unmap_put(unmap);
413
414 return tx;
415}
416EXPORT_SYMBOL_GPL(async_syndrome_val);
417
418static int __init async_pq_init(void)
419{
420 pq_scribble_page = alloc_page(GFP_KERNEL);
421
422 if (pq_scribble_page)
423 return 0;
424
425 pr_err("%s: failed to allocate required spare page\n", __func__);
426
427 return -ENOMEM;
428}
429
430static void __exit async_pq_exit(void)
431{
432 __free_page(pq_scribble_page);
433}
434
435module_init(async_pq_init);
436module_exit(async_pq_exit);
437
438MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
439MODULE_LICENSE("GPL");
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#include <linux/gfp.h>
28
29/**
30 * pq_scribble_page - space to hold throwaway P or Q buffer for
31 * synchronous gen_syndrome
32 */
33static struct page *pq_scribble_page;
34
35/* the struct page *blocks[] parameter passed to async_gen_syndrome()
36 * and async_syndrome_val() contains the 'P' destination address at
37 * blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
38 *
39 * note: these are macros as they are used as lvalues
40 */
41#define P(b, d) (b[d-2])
42#define Q(b, d) (b[d-1])
43
44/**
45 * do_async_gen_syndrome - asynchronously calculate P and/or Q
46 */
47static __async_inline struct dma_async_tx_descriptor *
48do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
49 const unsigned char *scfs, unsigned int offset, int disks,
50 size_t len, dma_addr_t *dma_src,
51 struct async_submit_ctl *submit)
52{
53 struct dma_async_tx_descriptor *tx = NULL;
54 struct dma_device *dma = chan->device;
55 enum dma_ctrl_flags dma_flags = 0;
56 enum async_tx_flags flags_orig = submit->flags;
57 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
58 dma_async_tx_callback cb_param_orig = submit->cb_param;
59 int src_cnt = disks - 2;
60 unsigned char coefs[src_cnt];
61 unsigned short pq_src_cnt;
62 dma_addr_t dma_dest[2];
63 int src_off = 0;
64 int idx;
65 int i;
66
67 /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */
68 if (P(blocks, disks))
69 dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset,
70 len, DMA_BIDIRECTIONAL);
71 else
72 dma_flags |= DMA_PREP_PQ_DISABLE_P;
73 if (Q(blocks, disks))
74 dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset,
75 len, DMA_BIDIRECTIONAL);
76 else
77 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
78
79 /* convert source addresses being careful to collapse 'empty'
80 * sources and update the coefficients accordingly
81 */
82 for (i = 0, idx = 0; i < src_cnt; i++) {
83 if (blocks[i] == NULL)
84 continue;
85 dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len,
86 DMA_TO_DEVICE);
87 coefs[idx] = scfs[i];
88 idx++;
89 }
90 src_cnt = idx;
91
92 while (src_cnt > 0) {
93 submit->flags = flags_orig;
94 pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
95 /* if we are submitting additional pqs, leave the chain open,
96 * clear the callback parameters, and leave the destination
97 * buffers mapped
98 */
99 if (src_cnt > pq_src_cnt) {
100 submit->flags &= ~ASYNC_TX_ACK;
101 submit->flags |= ASYNC_TX_FENCE;
102 dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP;
103 submit->cb_fn = NULL;
104 submit->cb_param = NULL;
105 } else {
106 dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP;
107 submit->cb_fn = cb_fn_orig;
108 submit->cb_param = cb_param_orig;
109 if (cb_fn_orig)
110 dma_flags |= DMA_PREP_INTERRUPT;
111 }
112 if (submit->flags & ASYNC_TX_FENCE)
113 dma_flags |= DMA_PREP_FENCE;
114
115 /* Since we have clobbered the src_list we are committed
116 * to doing this asynchronously. Drivers force forward
117 * progress in case they can not provide a descriptor
118 */
119 for (;;) {
120 tx = dma->device_prep_dma_pq(chan, dma_dest,
121 &dma_src[src_off],
122 pq_src_cnt,
123 &coefs[src_off], len,
124 dma_flags);
125 if (likely(tx))
126 break;
127 async_tx_quiesce(&submit->depend_tx);
128 dma_async_issue_pending(chan);
129 }
130
131 async_tx_submit(chan, tx, submit);
132 submit->depend_tx = tx;
133
134 /* drop completed sources */
135 src_cnt -= pq_src_cnt;
136 src_off += pq_src_cnt;
137
138 dma_flags |= DMA_PREP_CONTINUE;
139 }
140
141 return tx;
142}
143
144/**
145 * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
146 */
147static void
148do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
149 size_t len, struct async_submit_ctl *submit)
150{
151 void **srcs;
152 int i;
153
154 if (submit->scribble)
155 srcs = submit->scribble;
156 else
157 srcs = (void **) blocks;
158
159 for (i = 0; i < disks; i++) {
160 if (blocks[i] == NULL) {
161 BUG_ON(i > disks - 3); /* P or Q can't be zero */
162 srcs[i] = (void*)raid6_empty_zero_page;
163 } else
164 srcs[i] = page_address(blocks[i]) + offset;
165 }
166 raid6_call.gen_syndrome(disks, len, srcs);
167 async_tx_sync_epilog(submit);
168}
169
170/**
171 * async_gen_syndrome - asynchronously calculate a raid6 syndrome
172 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
173 * @offset: common offset into each block (src and dest) to start transaction
174 * @disks: number of blocks (including missing P or Q, see below)
175 * @len: length of operation in bytes
176 * @submit: submission/completion modifiers
177 *
178 * General note: This routine assumes a field of GF(2^8) with a
179 * primitive polynomial of 0x11d and a generator of {02}.
180 *
181 * 'disks' note: callers can optionally omit either P or Q (but not
182 * both) from the calculation by setting blocks[disks-2] or
183 * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <=
184 * PAGE_SIZE as a temporary buffer of this size is used in the
185 * synchronous path. 'disks' always accounts for both destination
186 * buffers. If any source buffers (blocks[i] where i < disks - 2) are
187 * set to NULL those buffers will be replaced with the raid6_zero_page
188 * in the synchronous path and omitted in the hardware-asynchronous
189 * path.
190 *
191 * 'blocks' note: if submit->scribble is NULL then the contents of
192 * 'blocks' may be overwritten to perform address conversions
193 * (dma_map_page() or page_address()).
194 */
195struct dma_async_tx_descriptor *
196async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
197 size_t len, struct async_submit_ctl *submit)
198{
199 int src_cnt = disks - 2;
200 struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
201 &P(blocks, disks), 2,
202 blocks, src_cnt, len);
203 struct dma_device *device = chan ? chan->device : NULL;
204 dma_addr_t *dma_src = NULL;
205
206 BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));
207
208 if (submit->scribble)
209 dma_src = submit->scribble;
210 else if (sizeof(dma_addr_t) <= sizeof(struct page *))
211 dma_src = (dma_addr_t *) blocks;
212
213 if (dma_src && device &&
214 (src_cnt <= dma_maxpq(device, 0) ||
215 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
216 is_dma_pq_aligned(device, offset, 0, len)) {
217 /* run the p+q asynchronously */
218 pr_debug("%s: (async) disks: %d len: %zu\n",
219 __func__, disks, len);
220 return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset,
221 disks, len, dma_src, submit);
222 }
223
224 /* run the pq synchronously */
225 pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
226
227 /* wait for any prerequisite operations */
228 async_tx_quiesce(&submit->depend_tx);
229
230 if (!P(blocks, disks)) {
231 P(blocks, disks) = pq_scribble_page;
232 BUG_ON(len + offset > PAGE_SIZE);
233 }
234 if (!Q(blocks, disks)) {
235 Q(blocks, disks) = pq_scribble_page;
236 BUG_ON(len + offset > PAGE_SIZE);
237 }
238 do_sync_gen_syndrome(blocks, offset, disks, len, submit);
239
240 return NULL;
241}
242EXPORT_SYMBOL_GPL(async_gen_syndrome);
243
244static inline struct dma_chan *
245pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len)
246{
247 #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
248 return NULL;
249 #endif
250 return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks,
251 disks, len);
252}
253
254/**
255 * async_syndrome_val - asynchronously validate a raid6 syndrome
256 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
257 * @offset: common offset into each block (src and dest) to start transaction
258 * @disks: number of blocks (including missing P or Q, see below)
259 * @len: length of operation in bytes
260 * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
261 * @spare: temporary result buffer for the synchronous case
262 * @submit: submission / completion modifiers
263 *
264 * The same notes from async_gen_syndrome apply to the 'blocks',
265 * and 'disks' parameters of this routine. The synchronous path
266 * requires a temporary result buffer and submit->scribble to be
267 * specified.
268 */
269struct dma_async_tx_descriptor *
270async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
271 size_t len, enum sum_check_flags *pqres, struct page *spare,
272 struct async_submit_ctl *submit)
273{
274 struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
275 struct dma_device *device = chan ? chan->device : NULL;
276 struct dma_async_tx_descriptor *tx;
277 unsigned char coefs[disks-2];
278 enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
279 dma_addr_t *dma_src = NULL;
280 int src_cnt = 0;
281
282 BUG_ON(disks < 4);
283
284 if (submit->scribble)
285 dma_src = submit->scribble;
286 else if (sizeof(dma_addr_t) <= sizeof(struct page *))
287 dma_src = (dma_addr_t *) blocks;
288
289 if (dma_src && device && disks <= dma_maxpq(device, 0) &&
290 is_dma_pq_aligned(device, offset, 0, len)) {
291 struct device *dev = device->dev;
292 dma_addr_t *pq = &dma_src[disks-2];
293 int i;
294
295 pr_debug("%s: (async) disks: %d len: %zu\n",
296 __func__, disks, len);
297 if (!P(blocks, disks))
298 dma_flags |= DMA_PREP_PQ_DISABLE_P;
299 else
300 pq[0] = dma_map_page(dev, P(blocks, disks),
301 offset, len,
302 DMA_TO_DEVICE);
303 if (!Q(blocks, disks))
304 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
305 else
306 pq[1] = dma_map_page(dev, Q(blocks, disks),
307 offset, len,
308 DMA_TO_DEVICE);
309
310 if (submit->flags & ASYNC_TX_FENCE)
311 dma_flags |= DMA_PREP_FENCE;
312 for (i = 0; i < disks-2; i++)
313 if (likely(blocks[i])) {
314 dma_src[src_cnt] = dma_map_page(dev, blocks[i],
315 offset, len,
316 DMA_TO_DEVICE);
317 coefs[src_cnt] = raid6_gfexp[i];
318 src_cnt++;
319 }
320
321 for (;;) {
322 tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
323 src_cnt,
324 coefs,
325 len, pqres,
326 dma_flags);
327 if (likely(tx))
328 break;
329 async_tx_quiesce(&submit->depend_tx);
330 dma_async_issue_pending(chan);
331 }
332 async_tx_submit(chan, tx, submit);
333
334 return tx;
335 } else {
336 struct page *p_src = P(blocks, disks);
337 struct page *q_src = Q(blocks, disks);
338 enum async_tx_flags flags_orig = submit->flags;
339 dma_async_tx_callback cb_fn_orig = submit->cb_fn;
340 void *scribble = submit->scribble;
341 void *cb_param_orig = submit->cb_param;
342 void *p, *q, *s;
343
344 pr_debug("%s: (sync) disks: %d len: %zu\n",
345 __func__, disks, len);
346
347 /* caller must provide a temporary result buffer and
348 * allow the input parameters to be preserved
349 */
350 BUG_ON(!spare || !scribble);
351
352 /* wait for any prerequisite operations */
353 async_tx_quiesce(&submit->depend_tx);
354
355 /* recompute p and/or q into the temporary buffer and then
356 * check to see the result matches the current value
357 */
358 tx = NULL;
359 *pqres = 0;
360 if (p_src) {
361 init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
362 NULL, NULL, scribble);
363 tx = async_xor(spare, blocks, offset, disks-2, len, submit);
364 async_tx_quiesce(&tx);
365 p = page_address(p_src) + offset;
366 s = page_address(spare) + offset;
367 *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
368 }
369
370 if (q_src) {
371 P(blocks, disks) = NULL;
372 Q(blocks, disks) = spare;
373 init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
374 tx = async_gen_syndrome(blocks, offset, disks, len, submit);
375 async_tx_quiesce(&tx);
376 q = page_address(q_src) + offset;
377 s = page_address(spare) + offset;
378 *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
379 }
380
381 /* restore P, Q and submit */
382 P(blocks, disks) = p_src;
383 Q(blocks, disks) = q_src;
384
385 submit->cb_fn = cb_fn_orig;
386 submit->cb_param = cb_param_orig;
387 submit->flags = flags_orig;
388 async_tx_sync_epilog(submit);
389
390 return NULL;
391 }
392}
393EXPORT_SYMBOL_GPL(async_syndrome_val);
394
395static int __init async_pq_init(void)
396{
397 pq_scribble_page = alloc_page(GFP_KERNEL);
398
399 if (pq_scribble_page)
400 return 0;
401
402 pr_err("%s: failed to allocate required spare page\n", __func__);
403
404 return -ENOMEM;
405}
406
407static void __exit async_pq_exit(void)
408{
409 put_page(pq_scribble_page);
410}
411
412module_init(async_pq_init);
413module_exit(async_pq_exit);
414
415MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
416MODULE_LICENSE("GPL");