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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com>4 * Copyright(c) 2009 Intel Corporation5 */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 for16 * synchronous gen_syndrome17 */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 at22 * blocks[disks-2] and the 'Q' destination address at blocks[disks-1]23 *24 * note: these are macros as they are used as lvalues25 */26#define P(b, d) (b[d-2])27#define Q(b, d) (b[d-1])28 29#define MAX_DISKS 25530 31/*32 * do_async_gen_syndrome - asynchronously calculate P and/or Q33 */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 destination56 * buffers mapped57 */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 provide73 * a descriptor74 */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 syndrome105 */106static void107do_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 else117 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 } else138 raid6_call.gen_syndrome(disks, len, srcs);139 async_tx_sync_epilog(submit);140}141 142static inline bool143is_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, offs[i], 0, len))150 return false;151 }152 return true;153}154 155/**156 * async_gen_syndrome - asynchronously calculate a raid6 syndrome157 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1158 * @offsets: offset array into each block (src and dest) to start transaction159 * @disks: number of blocks (including missing P or Q, see below)160 * @len: length of operation in bytes161 * @submit: submission/completion modifiers162 *163 * General note: This routine assumes a field of GF(2^8) with a164 * primitive polynomial of 0x11d and a generator of {02}.165 *166 * 'disks' note: callers can optionally omit either P or Q (but not167 * both) from the calculation by setting blocks[disks-2] or168 * 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 the170 * synchronous path. 'disks' always accounts for both destination171 * buffers. If any source buffers (blocks[i] where i < disks - 2) are172 * set to NULL those buffers will be replaced with the raid6_zero_page173 * in the synchronous path and omitted in the hardware-asynchronous174 * path.175 */176struct dma_async_tx_descriptor *177async_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(device->dev, 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(device, 0) ||195 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&196 is_dma_pq_aligned_offs(device, offsets, 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 accordingly208 */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 mapping223 */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, coefs, 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(&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}269EXPORT_SYMBOL_GPL(async_gen_syndrome);270 271static inline struct dma_chan *272pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len)273{274 #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA275 return NULL;276 #endif277 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 syndrome283 * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1284 * @offsets: common offset into each block (src and dest) to start transaction285 * @disks: number of blocks (including missing P or Q, see below)286 * @len: length of operation in bytes287 * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set288 * @spare: temporary result buffer for the synchronous case289 * @s_off: spare buffer page offset290 * @submit: submission / completion modifiers291 *292 * The same notes from async_gen_syndrome apply to the 'blocks',293 * and 'disks' parameters of this routine. The synchronous path294 * requires a temporary result buffer and submit->scribble to be295 * specified.296 */297struct dma_async_tx_descriptor *298async_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(device->dev, disks, GFP_NOWAIT);313 314 if (unmap && disks <= dma_maxpq(device, 0) &&315 is_dma_pq_aligned_offs(device, offsets, 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(&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 and388 * allow the input parameters to be preserved389 */390 BUG_ON(!spare || !scribble);391 392 /* wait for any prerequisite operations */393 async_tx_quiesce(&submit->depend_tx);394 395 /* recompute p and/or q into the temporary buffer and then396 * check to see the result matches the current value397 */398 tx = NULL;399 *pqres = 0;400 if (p_src) {401 init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,402 NULL, NULL, scribble);403 tx = async_xor_offs(spare, s_off,404 blocks, offsets, disks-2, len, submit);405 async_tx_quiesce(&tx);406 p = page_address(p_src) + p_off;407 s = page_address(spare) + s_off;408 *pqres |= !!memcmp(p, s, 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(submit, 0, NULL, NULL, NULL, scribble);416 tx = async_gen_syndrome(blocks, offsets, disks,417 len, submit);418 async_tx_quiesce(&tx);419 q = page_address(q_src) + q_off;420 s = page_address(spare) + s_off;421 *pqres |= !!memcmp(q, s, 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}440EXPORT_SYMBOL_GPL(async_syndrome_val);441 442static 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 454static void __exit async_pq_exit(void)455{456 __free_page(pq_scribble_page);457}458 459module_init(async_pq_init);460module_exit(async_pq_exit);461 462MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");463MODULE_LICENSE("GPL");464