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 */ 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(&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, offs[i], 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(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 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, 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 } 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 * @offset: 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(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 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(&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(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 } 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