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 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 */ 162 struct dma_async_tx_descriptor * 163 async_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 } 253 EXPORT_SYMBOL_GPL(async_gen_syndrome); 254 255 static inline struct dma_chan * 256 pq_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 */ 280 struct dma_async_tx_descriptor * 281 async_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 } 416 EXPORT_SYMBOL_GPL(async_syndrome_val); 417 418 static 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 } 429 430 static void __exit async_pq_exit(void) 431 { 432 __free_page(pq_scribble_page); 433 } 434 435 module_init(async_pq_init); 436 module_exit(async_pq_exit); 437 438 MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation"); 439 MODULE_LICENSE("GPL"); 440