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22#include <linux/kernel.h>
23#include <linux/interrupt.h>
24#include <linux/module.h>
25#include <linux/dma-mapping.h>
26#include <linux/raid/pq.h>
27#include <linux/async_tx.h>
28#include <linux/gfp.h>
29
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32
33
34static struct page *pq_scribble_page;
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41
42#define P(b, d) (b[d-2])
43#define Q(b, d) (b[d-1])
44
45
46
47
48static __async_inline struct dma_async_tx_descriptor *
49do_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
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
81
82
83 for (i = 0, idx = 0; i < src_cnt; i++) {
84 if (blocks[i] == NULL)
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
97
98
99
100 if (src_cnt > pq_src_cnt) {
101 submit->flags &= ~ASYNC_TX_ACK;
102 submit->flags |= ASYNC_TX_FENCE;
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 }
113 if (submit->flags & ASYNC_TX_FENCE)
114 dma_flags |= DMA_PREP_FENCE;
115
116
117
118
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
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
147
148static void
149do_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++) {
161 if (blocks[i] == NULL) {
162 BUG_ON(i > disks - 3);
163 srcs[i] = (void*)raid6_empty_zero_page;
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}
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195
196struct dma_async_tx_descriptor *
197async_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) ||
216 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
217 is_dma_pq_aligned(device, offset, 0, len)) {
218
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
226 pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
227
228
229 async_tx_quiesce(&submit->depend_tx);
230
231 if (!P(blocks, disks)) {
232 P(blocks, disks) = pq_scribble_page;
233 BUG_ON(len + offset > PAGE_SIZE);
234 }
235 if (!Q(blocks, disks)) {
236 Q(blocks, disks) = pq_scribble_page;
237 BUG_ON(len + offset > PAGE_SIZE);
238 }
239 do_sync_gen_syndrome(blocks, offset, disks, len, submit);
240
241 return NULL;
242}
243EXPORT_SYMBOL_GPL(async_gen_syndrome);
244
245static inline struct dma_chan *
246pq_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}
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269
270struct dma_async_tx_descriptor *
271async_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{
275 struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
276 struct dma_device *device = chan ? chan->device : NULL;
277 struct dma_async_tx_descriptor *tx;
278 unsigned char coefs[disks-2];
279 enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
280 dma_addr_t *dma_src = NULL;
281 int src_cnt = 0;
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
290 if (dma_src && device && disks <= dma_maxpq(device, 0) &&
291 is_dma_pq_aligned(device, offset, 0, len)) {
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;
300 else
301 pq[0] = dma_map_page(dev, P(blocks, disks),
302 offset, len,
303 DMA_TO_DEVICE);
304 if (!Q(blocks, disks))
305 dma_flags |= DMA_PREP_PQ_DISABLE_Q;
306 else
307 pq[1] = dma_map_page(dev, Q(blocks, disks),
308 offset, len,
309 DMA_TO_DEVICE);
310
311 if (submit->flags & ASYNC_TX_FENCE)
312 dma_flags |= DMA_PREP_FENCE;
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 }
321
322 for (;;) {
323 tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
324 src_cnt,
325 coefs,
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
349
350
351 BUG_ON(!spare || !scribble);
352
353
354 async_tx_quiesce(&submit->depend_tx);
355
356
357
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
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}
394EXPORT_SYMBOL_GPL(async_syndrome_val);
395
396static int __init async_pq_init(void)
397{
398 pq_scribble_page = alloc_page(GFP_KERNEL);
399
400 if (pq_scribble_page)
401 return 0;
402
403 pr_err("%s: failed to allocate required spare page\n", __func__);
404
405 return -ENOMEM;
406}
407
408static void __exit async_pq_exit(void)
409{
410 put_page(pq_scribble_page);
411}
412
413module_init(async_pq_init);
414module_exit(async_pq_exit);
415
416MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
417MODULE_LICENSE("GPL");
418