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 | * struct pq_scribble_page - space to hold throwaway P or Q buffer for |
16 | * synchronous gen_syndrome |
17 | */ |
18 | static 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 | */ |
34 | static __async_inline struct dma_async_tx_descriptor * |
35 | do_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(tx: &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 | */ |
106 | static void |
107 | do_sync_gen_syndrome(struct page **blocks, unsigned int *offsets, 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]) + offsets[i]; |
125 | |
126 | if (i < disks - 2) { |
127 | stop = i; |
128 | if (start == -1) |
129 | start = i; |
130 | } |
131 | } |
132 | } |
133 | if (submit->flags & ASYNC_TX_PQ_XOR_DST) { |
134 | BUG_ON(!raid6_call.xor_syndrome); |
135 | if (start >= 0) |
136 | raid6_call.xor_syndrome(disks, start, stop, len, srcs); |
137 | } else |
138 | raid6_call.gen_syndrome(disks, len, srcs); |
139 | async_tx_sync_epilog(submit); |
140 | } |
141 | |
142 | static inline bool |
143 | is_dma_pq_aligned_offs(struct dma_device *dev, unsigned int *offs, |
144 | int src_cnt, size_t len) |
145 | { |
146 | int i; |
147 | |
148 | for (i = 0; i < src_cnt; i++) { |
149 | if (!is_dma_pq_aligned(dev, off1: offs[i], off2: 0, len)) |
150 | return false; |
151 | } |
152 | return true; |
153 | } |
154 | |
155 | /** |
156 | * async_gen_syndrome - asynchronously calculate a raid6 syndrome |
157 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 |
158 | * @offsets: offset array into each block (src and dest) to start transaction |
159 | * @disks: number of blocks (including missing P or Q, see below) |
160 | * @len: length of operation in bytes |
161 | * @submit: submission/completion modifiers |
162 | * |
163 | * General note: This routine assumes a field of GF(2^8) with a |
164 | * primitive polynomial of 0x11d and a generator of {02}. |
165 | * |
166 | * 'disks' note: callers can optionally omit either P or Q (but not |
167 | * both) from the calculation by setting blocks[disks-2] or |
168 | * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <= |
169 | * PAGE_SIZE as a temporary buffer of this size is used in the |
170 | * synchronous path. 'disks' always accounts for both destination |
171 | * buffers. If any source buffers (blocks[i] where i < disks - 2) are |
172 | * set to NULL those buffers will be replaced with the raid6_zero_page |
173 | * in the synchronous path and omitted in the hardware-asynchronous |
174 | * path. |
175 | */ |
176 | struct dma_async_tx_descriptor * |
177 | async_gen_syndrome(struct page **blocks, unsigned int *offsets, int disks, |
178 | size_t len, struct async_submit_ctl *submit) |
179 | { |
180 | int src_cnt = disks - 2; |
181 | struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, |
182 | &P(blocks, disks), 2, |
183 | blocks, src_cnt, len); |
184 | struct dma_device *device = chan ? chan->device : NULL; |
185 | struct dmaengine_unmap_data *unmap = NULL; |
186 | |
187 | BUG_ON(disks > MAX_DISKS || !(P(blocks, disks) || Q(blocks, disks))); |
188 | |
189 | if (device) |
190 | unmap = dmaengine_get_unmap_data(dev: device->dev, nr: disks, GFP_NOWAIT); |
191 | |
192 | /* XORing P/Q is only implemented in software */ |
193 | if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) && |
194 | (src_cnt <= dma_maxpq(dma: device, flags: 0) || |
195 | dma_maxpq(dma: device, flags: DMA_PREP_CONTINUE) > 0) && |
196 | is_dma_pq_aligned_offs(dev: device, offs: offsets, src_cnt: disks, len)) { |
197 | struct dma_async_tx_descriptor *tx; |
198 | enum dma_ctrl_flags dma_flags = 0; |
199 | unsigned char coefs[MAX_DISKS]; |
200 | int i, j; |
201 | |
202 | /* run the p+q asynchronously */ |
203 | pr_debug("%s: (async) disks: %d len: %zu\n" , |
204 | __func__, disks, len); |
205 | |
206 | /* convert source addresses being careful to collapse 'empty' |
207 | * sources and update the coefficients accordingly |
208 | */ |
209 | unmap->len = len; |
210 | for (i = 0, j = 0; i < src_cnt; i++) { |
211 | if (blocks[i] == NULL) |
212 | continue; |
213 | unmap->addr[j] = dma_map_page(device->dev, blocks[i], |
214 | offsets[i], len, DMA_TO_DEVICE); |
215 | coefs[j] = raid6_gfexp[i]; |
216 | unmap->to_cnt++; |
217 | j++; |
218 | } |
219 | |
220 | /* |
221 | * DMAs use destinations as sources, |
222 | * so use BIDIRECTIONAL mapping |
223 | */ |
224 | unmap->bidi_cnt++; |
225 | if (P(blocks, disks)) |
226 | unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks), |
227 | P(offsets, disks), |
228 | len, DMA_BIDIRECTIONAL); |
229 | else { |
230 | unmap->addr[j++] = 0; |
231 | dma_flags |= DMA_PREP_PQ_DISABLE_P; |
232 | } |
233 | |
234 | unmap->bidi_cnt++; |
235 | if (Q(blocks, disks)) |
236 | unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks), |
237 | Q(offsets, disks), |
238 | len, DMA_BIDIRECTIONAL); |
239 | else { |
240 | unmap->addr[j++] = 0; |
241 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; |
242 | } |
243 | |
244 | tx = do_async_gen_syndrome(chan, scfs: coefs, disks: j, unmap, dma_flags, submit); |
245 | dmaengine_unmap_put(unmap); |
246 | return tx; |
247 | } |
248 | |
249 | dmaengine_unmap_put(unmap); |
250 | |
251 | /* run the pq synchronously */ |
252 | pr_debug("%s: (sync) disks: %d len: %zu\n" , __func__, disks, len); |
253 | |
254 | /* wait for any prerequisite operations */ |
255 | async_tx_quiesce(tx: &submit->depend_tx); |
256 | |
257 | if (!P(blocks, disks)) { |
258 | P(blocks, disks) = pq_scribble_page; |
259 | P(offsets, disks) = 0; |
260 | } |
261 | if (!Q(blocks, disks)) { |
262 | Q(blocks, disks) = pq_scribble_page; |
263 | Q(offsets, disks) = 0; |
264 | } |
265 | do_sync_gen_syndrome(blocks, offsets, disks, len, submit); |
266 | |
267 | return NULL; |
268 | } |
269 | EXPORT_SYMBOL_GPL(async_gen_syndrome); |
270 | |
271 | static inline struct dma_chan * |
272 | pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len) |
273 | { |
274 | #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA |
275 | return NULL; |
276 | #endif |
277 | return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks, |
278 | disks, len); |
279 | } |
280 | |
281 | /** |
282 | * async_syndrome_val - asynchronously validate a raid6 syndrome |
283 | * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 |
284 | * @offsets: common offset into each block (src and dest) to start transaction |
285 | * @disks: number of blocks (including missing P or Q, see below) |
286 | * @len: length of operation in bytes |
287 | * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set |
288 | * @spare: temporary result buffer for the synchronous case |
289 | * @s_off: spare buffer page offset |
290 | * @submit: submission / completion modifiers |
291 | * |
292 | * The same notes from async_gen_syndrome apply to the 'blocks', |
293 | * and 'disks' parameters of this routine. The synchronous path |
294 | * requires a temporary result buffer and submit->scribble to be |
295 | * specified. |
296 | */ |
297 | struct dma_async_tx_descriptor * |
298 | async_syndrome_val(struct page **blocks, unsigned int *offsets, int disks, |
299 | size_t len, enum sum_check_flags *pqres, struct page *spare, |
300 | unsigned int s_off, struct async_submit_ctl *submit) |
301 | { |
302 | struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len); |
303 | struct dma_device *device = chan ? chan->device : NULL; |
304 | struct dma_async_tx_descriptor *tx; |
305 | unsigned char coefs[MAX_DISKS]; |
306 | enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0; |
307 | struct dmaengine_unmap_data *unmap = NULL; |
308 | |
309 | BUG_ON(disks < 4 || disks > MAX_DISKS); |
310 | |
311 | if (device) |
312 | unmap = dmaengine_get_unmap_data(dev: device->dev, nr: disks, GFP_NOWAIT); |
313 | |
314 | if (unmap && disks <= dma_maxpq(dma: device, flags: 0) && |
315 | is_dma_pq_aligned_offs(dev: device, offs: offsets, src_cnt: disks, len)) { |
316 | struct device *dev = device->dev; |
317 | dma_addr_t pq[2]; |
318 | int i, j = 0, src_cnt = 0; |
319 | |
320 | pr_debug("%s: (async) disks: %d len: %zu\n" , |
321 | __func__, disks, len); |
322 | |
323 | unmap->len = len; |
324 | for (i = 0; i < disks-2; i++) |
325 | if (likely(blocks[i])) { |
326 | unmap->addr[j] = dma_map_page(dev, blocks[i], |
327 | offsets[i], len, |
328 | DMA_TO_DEVICE); |
329 | coefs[j] = raid6_gfexp[i]; |
330 | unmap->to_cnt++; |
331 | src_cnt++; |
332 | j++; |
333 | } |
334 | |
335 | if (!P(blocks, disks)) { |
336 | pq[0] = 0; |
337 | dma_flags |= DMA_PREP_PQ_DISABLE_P; |
338 | } else { |
339 | pq[0] = dma_map_page(dev, P(blocks, disks), |
340 | P(offsets, disks), len, |
341 | DMA_TO_DEVICE); |
342 | unmap->addr[j++] = pq[0]; |
343 | unmap->to_cnt++; |
344 | } |
345 | if (!Q(blocks, disks)) { |
346 | pq[1] = 0; |
347 | dma_flags |= DMA_PREP_PQ_DISABLE_Q; |
348 | } else { |
349 | pq[1] = dma_map_page(dev, Q(blocks, disks), |
350 | Q(offsets, disks), len, |
351 | DMA_TO_DEVICE); |
352 | unmap->addr[j++] = pq[1]; |
353 | unmap->to_cnt++; |
354 | } |
355 | |
356 | if (submit->flags & ASYNC_TX_FENCE) |
357 | dma_flags |= DMA_PREP_FENCE; |
358 | for (;;) { |
359 | tx = device->device_prep_dma_pq_val(chan, pq, |
360 | unmap->addr, |
361 | src_cnt, |
362 | coefs, |
363 | len, pqres, |
364 | dma_flags); |
365 | if (likely(tx)) |
366 | break; |
367 | async_tx_quiesce(tx: &submit->depend_tx); |
368 | dma_async_issue_pending(chan); |
369 | } |
370 | |
371 | dma_set_unmap(tx, unmap); |
372 | async_tx_submit(chan, tx, submit); |
373 | } else { |
374 | struct page *p_src = P(blocks, disks); |
375 | unsigned int p_off = P(offsets, disks); |
376 | struct page *q_src = Q(blocks, disks); |
377 | unsigned int q_off = Q(offsets, disks); |
378 | enum async_tx_flags flags_orig = submit->flags; |
379 | dma_async_tx_callback cb_fn_orig = submit->cb_fn; |
380 | void *scribble = submit->scribble; |
381 | void *cb_param_orig = submit->cb_param; |
382 | void *p, *q, *s; |
383 | |
384 | pr_debug("%s: (sync) disks: %d len: %zu\n" , |
385 | __func__, disks, len); |
386 | |
387 | /* caller must provide a temporary result buffer and |
388 | * allow the input parameters to be preserved |
389 | */ |
390 | BUG_ON(!spare || !scribble); |
391 | |
392 | /* wait for any prerequisite operations */ |
393 | async_tx_quiesce(tx: &submit->depend_tx); |
394 | |
395 | /* recompute p and/or q into the temporary buffer and then |
396 | * check to see the result matches the current value |
397 | */ |
398 | tx = NULL; |
399 | *pqres = 0; |
400 | if (p_src) { |
401 | init_async_submit(args: submit, flags: ASYNC_TX_XOR_ZERO_DST, NULL, |
402 | NULL, NULL, scribble); |
403 | tx = async_xor_offs(dest: spare, offset: s_off, |
404 | src_list: blocks, src_offset: offsets, src_cnt: disks-2, len, submit); |
405 | async_tx_quiesce(tx: &tx); |
406 | p = page_address(p_src) + p_off; |
407 | s = page_address(spare) + s_off; |
408 | *pqres |= !!memcmp(p, q: s, size: len) << SUM_CHECK_P; |
409 | } |
410 | |
411 | if (q_src) { |
412 | P(blocks, disks) = NULL; |
413 | Q(blocks, disks) = spare; |
414 | Q(offsets, disks) = s_off; |
415 | init_async_submit(args: submit, flags: 0, NULL, NULL, NULL, scribble); |
416 | tx = async_gen_syndrome(blocks, offsets, disks, |
417 | len, submit); |
418 | async_tx_quiesce(tx: &tx); |
419 | q = page_address(q_src) + q_off; |
420 | s = page_address(spare) + s_off; |
421 | *pqres |= !!memcmp(p: q, q: s, size: len) << SUM_CHECK_Q; |
422 | } |
423 | |
424 | /* restore P, Q and submit */ |
425 | P(blocks, disks) = p_src; |
426 | P(offsets, disks) = p_off; |
427 | Q(blocks, disks) = q_src; |
428 | Q(offsets, disks) = q_off; |
429 | |
430 | submit->cb_fn = cb_fn_orig; |
431 | submit->cb_param = cb_param_orig; |
432 | submit->flags = flags_orig; |
433 | async_tx_sync_epilog(submit); |
434 | tx = NULL; |
435 | } |
436 | dmaengine_unmap_put(unmap); |
437 | |
438 | return tx; |
439 | } |
440 | EXPORT_SYMBOL_GPL(async_syndrome_val); |
441 | |
442 | static int __init async_pq_init(void) |
443 | { |
444 | pq_scribble_page = alloc_page(GFP_KERNEL); |
445 | |
446 | if (pq_scribble_page) |
447 | return 0; |
448 | |
449 | pr_err("%s: failed to allocate required spare page\n" , __func__); |
450 | |
451 | return -ENOMEM; |
452 | } |
453 | |
454 | static void __exit async_pq_exit(void) |
455 | { |
456 | __free_page(pq_scribble_page); |
457 | } |
458 | |
459 | module_init(async_pq_init); |
460 | module_exit(async_pq_exit); |
461 | |
462 | MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation" ); |
463 | MODULE_LICENSE("GPL" ); |
464 | |