| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef _LINUX_SCATTERLIST_H |
| 3 | #define _LINUX_SCATTERLIST_H |
| 4 | |
| 5 | #include <linux/string.h> |
| 6 | #include <linux/types.h> |
| 7 | #include <linux/bug.h> |
| 8 | #include <linux/mm.h> |
| 9 | #include <asm/io.h> |
| 10 | |
| 11 | struct scatterlist { |
| 12 | unsigned long page_link; |
| 13 | unsigned int offset; |
| 14 | unsigned int length; |
| 15 | dma_addr_t dma_address; |
| 16 | #ifdef CONFIG_NEED_SG_DMA_LENGTH |
| 17 | unsigned int dma_length; |
| 18 | #endif |
| 19 | #ifdef CONFIG_NEED_SG_DMA_FLAGS |
| 20 | unsigned int dma_flags; |
| 21 | #endif |
| 22 | }; |
| 23 | |
| 24 | /* |
| 25 | * These macros should be used after a dma_map_sg call has been done |
| 26 | * to get bus addresses of each of the SG entries and their lengths. |
| 27 | * You should only work with the number of sg entries dma_map_sg |
| 28 | * returns, or alternatively stop on the first sg_dma_len(sg) which |
| 29 | * is 0. |
| 30 | */ |
| 31 | #define sg_dma_address(sg) ((sg)->dma_address) |
| 32 | |
| 33 | #ifdef CONFIG_NEED_SG_DMA_LENGTH |
| 34 | #define sg_dma_len(sg) ((sg)->dma_length) |
| 35 | #else |
| 36 | #define sg_dma_len(sg) ((sg)->length) |
| 37 | #endif |
| 38 | |
| 39 | struct sg_table { |
| 40 | struct scatterlist *sgl; /* the list */ |
| 41 | unsigned int nents; /* number of mapped entries */ |
| 42 | unsigned int orig_nents; /* original size of list */ |
| 43 | }; |
| 44 | |
| 45 | struct sg_append_table { |
| 46 | struct sg_table sgt; /* The scatter list table */ |
| 47 | struct scatterlist *prv; /* last populated sge in the table */ |
| 48 | unsigned int total_nents; /* Total entries in the table */ |
| 49 | }; |
| 50 | |
| 51 | /* |
| 52 | * Notes on SG table design. |
| 53 | * |
| 54 | * We use the unsigned long page_link field in the scatterlist struct to place |
| 55 | * the page pointer AND encode information about the sg table as well. The two |
| 56 | * lower bits are reserved for this information. |
| 57 | * |
| 58 | * If bit 0 is set, then the page_link contains a pointer to the next sg |
| 59 | * table list. Otherwise the next entry is at sg + 1. |
| 60 | * |
| 61 | * If bit 1 is set, then this sg entry is the last element in a list. |
| 62 | * |
| 63 | * See sg_next(). |
| 64 | * |
| 65 | */ |
| 66 | |
| 67 | #define SG_CHAIN 0x01UL |
| 68 | #define SG_END 0x02UL |
| 69 | |
| 70 | /* |
| 71 | * We overload the LSB of the page pointer to indicate whether it's |
| 72 | * a valid sg entry, or whether it points to the start of a new scatterlist. |
| 73 | * Those low bits are there for everyone! (thanks mason :-) |
| 74 | */ |
| 75 | #define SG_PAGE_LINK_MASK (SG_CHAIN | SG_END) |
| 76 | |
| 77 | static inline unsigned int __sg_flags(struct scatterlist *sg) |
| 78 | { |
| 79 | return sg->page_link & SG_PAGE_LINK_MASK; |
| 80 | } |
| 81 | |
| 82 | static inline struct scatterlist *sg_chain_ptr(struct scatterlist *sg) |
| 83 | { |
| 84 | return (struct scatterlist *)(sg->page_link & ~SG_PAGE_LINK_MASK); |
| 85 | } |
| 86 | |
| 87 | static inline bool sg_is_chain(struct scatterlist *sg) |
| 88 | { |
| 89 | return __sg_flags(sg) & SG_CHAIN; |
| 90 | } |
| 91 | |
| 92 | static inline bool sg_is_last(struct scatterlist *sg) |
| 93 | { |
| 94 | return __sg_flags(sg) & SG_END; |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * sg_assign_page - Assign a given page to an SG entry |
| 99 | * @sg: SG entry |
| 100 | * @page: The page |
| 101 | * |
| 102 | * Description: |
| 103 | * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
| 104 | * variant. |
| 105 | * |
| 106 | **/ |
| 107 | static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
| 108 | { |
| 109 | unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END); |
| 110 | |
| 111 | /* |
| 112 | * In order for the low bit stealing approach to work, pages |
| 113 | * must be aligned at a 32-bit boundary as a minimum. |
| 114 | */ |
| 115 | BUG_ON((unsigned long)page & SG_PAGE_LINK_MASK); |
| 116 | #ifdef CONFIG_DEBUG_SG |
| 117 | BUG_ON(sg_is_chain(sg)); |
| 118 | #endif |
| 119 | sg->page_link = page_link | (unsigned long) page; |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * sg_set_page - Set sg entry to point at given page |
| 124 | * @sg: SG entry |
| 125 | * @page: The page |
| 126 | * @len: Length of data |
| 127 | * @offset: Offset into page |
| 128 | * |
| 129 | * Description: |
| 130 | * Use this function to set an sg entry pointing at a page, never assign |
| 131 | * the page directly. We encode sg table information in the lower bits |
| 132 | * of the page pointer. See sg_page() for looking up the page belonging |
| 133 | * to an sg entry. |
| 134 | * |
| 135 | **/ |
| 136 | static inline void sg_set_page(struct scatterlist *sg, struct page *page, |
| 137 | unsigned int len, unsigned int offset) |
| 138 | { |
| 139 | sg_assign_page(sg, page); |
| 140 | sg->offset = offset; |
| 141 | sg->length = len; |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * sg_set_folio - Set sg entry to point at given folio |
| 146 | * @sg: SG entry |
| 147 | * @folio: The folio |
| 148 | * @len: Length of data |
| 149 | * @offset: Offset into folio |
| 150 | * |
| 151 | * Description: |
| 152 | * Use this function to set an sg entry pointing at a folio, never assign |
| 153 | * the folio directly. We encode sg table information in the lower bits |
| 154 | * of the folio pointer. See sg_page() for looking up the page belonging |
| 155 | * to an sg entry. |
| 156 | * |
| 157 | **/ |
| 158 | static inline void sg_set_folio(struct scatterlist *sg, struct folio *folio, |
| 159 | size_t len, size_t offset) |
| 160 | { |
| 161 | WARN_ON_ONCE(len > UINT_MAX); |
| 162 | WARN_ON_ONCE(offset > UINT_MAX); |
| 163 | sg_assign_page(sg, &folio->page); |
| 164 | sg->offset = offset; |
| 165 | sg->length = len; |
| 166 | } |
| 167 | |
| 168 | static inline struct page *sg_page(struct scatterlist *sg) |
| 169 | { |
| 170 | #ifdef CONFIG_DEBUG_SG |
| 171 | BUG_ON(sg_is_chain(sg)); |
| 172 | #endif |
| 173 | return (struct page *)((sg)->page_link & ~SG_PAGE_LINK_MASK); |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * sg_set_buf - Set sg entry to point at given data |
| 178 | * @sg: SG entry |
| 179 | * @buf: Data |
| 180 | * @buflen: Data length |
| 181 | * |
| 182 | **/ |
| 183 | static inline void sg_set_buf(struct scatterlist *sg, const void *buf, |
| 184 | unsigned int buflen) |
| 185 | { |
| 186 | #ifdef CONFIG_DEBUG_SG |
| 187 | BUG_ON(!virt_addr_valid(buf)); |
| 188 | #endif |
| 189 | sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * Loop over each sg element, following the pointer to a new list if necessary |
| 194 | */ |
| 195 | #define for_each_sg(sglist, sg, nr, __i) \ |
| 196 | for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) |
| 197 | |
| 198 | /* |
| 199 | * Loop over each sg element in the given sg_table object. |
| 200 | */ |
| 201 | #define for_each_sgtable_sg(sgt, sg, i) \ |
| 202 | for_each_sg((sgt)->sgl, sg, (sgt)->orig_nents, i) |
| 203 | |
| 204 | /* |
| 205 | * Loop over each sg element in the given *DMA mapped* sg_table object. |
| 206 | * Please use sg_dma_address(sg) and sg_dma_len(sg) to extract DMA addresses |
| 207 | * of the each element. |
| 208 | */ |
| 209 | #define for_each_sgtable_dma_sg(sgt, sg, i) \ |
| 210 | for_each_sg((sgt)->sgl, sg, (sgt)->nents, i) |
| 211 | |
| 212 | static inline void __sg_chain(struct scatterlist *chain_sg, |
| 213 | struct scatterlist *sgl) |
| 214 | { |
| 215 | /* |
| 216 | * offset and length are unused for chain entry. Clear them. |
| 217 | */ |
| 218 | chain_sg->offset = 0; |
| 219 | chain_sg->length = 0; |
| 220 | |
| 221 | /* |
| 222 | * Set lowest bit to indicate a link pointer, and make sure to clear |
| 223 | * the termination bit if it happens to be set. |
| 224 | */ |
| 225 | chain_sg->page_link = ((unsigned long) sgl | SG_CHAIN) & ~SG_END; |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * sg_chain - Chain two sglists together |
| 230 | * @prv: First scatterlist |
| 231 | * @prv_nents: Number of entries in prv |
| 232 | * @sgl: Second scatterlist |
| 233 | * |
| 234 | * Description: |
| 235 | * Links @prv@ and @sgl@ together, to form a longer scatterlist. |
| 236 | * |
| 237 | **/ |
| 238 | static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
| 239 | struct scatterlist *sgl) |
| 240 | { |
| 241 | __sg_chain(&prv[prv_nents - 1], sgl); |
| 242 | } |
| 243 | |
| 244 | /** |
| 245 | * sg_mark_end - Mark the end of the scatterlist |
| 246 | * @sg: SG entryScatterlist |
| 247 | * |
| 248 | * Description: |
| 249 | * Marks the passed in sg entry as the termination point for the sg |
| 250 | * table. A call to sg_next() on this entry will return NULL. |
| 251 | * |
| 252 | **/ |
| 253 | static inline void sg_mark_end(struct scatterlist *sg) |
| 254 | { |
| 255 | /* |
| 256 | * Set termination bit, clear potential chain bit |
| 257 | */ |
| 258 | sg->page_link |= SG_END; |
| 259 | sg->page_link &= ~SG_CHAIN; |
| 260 | } |
| 261 | |
| 262 | /** |
| 263 | * sg_unmark_end - Undo setting the end of the scatterlist |
| 264 | * @sg: SG entryScatterlist |
| 265 | * |
| 266 | * Description: |
| 267 | * Removes the termination marker from the given entry of the scatterlist. |
| 268 | * |
| 269 | **/ |
| 270 | static inline void sg_unmark_end(struct scatterlist *sg) |
| 271 | { |
| 272 | sg->page_link &= ~SG_END; |
| 273 | } |
| 274 | |
| 275 | /* |
| 276 | * One 64-bit architectures there is a 4-byte padding in struct scatterlist |
| 277 | * (assuming also CONFIG_NEED_SG_DMA_LENGTH is set). Use this padding for DMA |
| 278 | * flags bits to indicate when a specific dma address is a bus address or the |
| 279 | * buffer may have been bounced via SWIOTLB. |
| 280 | */ |
| 281 | #ifdef CONFIG_NEED_SG_DMA_FLAGS |
| 282 | |
| 283 | #define SG_DMA_BUS_ADDRESS (1 << 0) |
| 284 | #define SG_DMA_SWIOTLB (1 << 1) |
| 285 | |
| 286 | /** |
| 287 | * sg_dma_is_bus_address - Return whether a given segment was marked |
| 288 | * as a bus address |
| 289 | * @sg: SG entry |
| 290 | * |
| 291 | * Description: |
| 292 | * Returns true if sg_dma_mark_bus_address() has been called on |
| 293 | * this segment. |
| 294 | **/ |
| 295 | static inline bool sg_dma_is_bus_address(struct scatterlist *sg) |
| 296 | { |
| 297 | return sg->dma_flags & SG_DMA_BUS_ADDRESS; |
| 298 | } |
| 299 | |
| 300 | /** |
| 301 | * sg_dma_mark_bus_address - Mark the scatterlist entry as a bus address |
| 302 | * @sg: SG entry |
| 303 | * |
| 304 | * Description: |
| 305 | * Marks the passed in sg entry to indicate that the dma_address is |
| 306 | * a bus address and doesn't need to be unmapped. This should only be |
| 307 | * used by dma_map_sg() implementations to mark bus addresses |
| 308 | * so they can be properly cleaned up in dma_unmap_sg(). |
| 309 | **/ |
| 310 | static inline void sg_dma_mark_bus_address(struct scatterlist *sg) |
| 311 | { |
| 312 | sg->dma_flags |= SG_DMA_BUS_ADDRESS; |
| 313 | } |
| 314 | |
| 315 | /** |
| 316 | * sg_unmark_bus_address - Unmark the scatterlist entry as a bus address |
| 317 | * @sg: SG entry |
| 318 | * |
| 319 | * Description: |
| 320 | * Clears the bus address mark. |
| 321 | **/ |
| 322 | static inline void sg_dma_unmark_bus_address(struct scatterlist *sg) |
| 323 | { |
| 324 | sg->dma_flags &= ~SG_DMA_BUS_ADDRESS; |
| 325 | } |
| 326 | |
| 327 | /** |
| 328 | * sg_dma_is_swiotlb - Return whether the scatterlist was marked for SWIOTLB |
| 329 | * bouncing |
| 330 | * @sg: SG entry |
| 331 | * |
| 332 | * Description: |
| 333 | * Returns true if the scatterlist was marked for SWIOTLB bouncing. Not all |
| 334 | * elements may have been bounced, so the caller would have to check |
| 335 | * individual SG entries with is_swiotlb_buffer(). |
| 336 | */ |
| 337 | static inline bool sg_dma_is_swiotlb(struct scatterlist *sg) |
| 338 | { |
| 339 | return sg->dma_flags & SG_DMA_SWIOTLB; |
| 340 | } |
| 341 | |
| 342 | /** |
| 343 | * sg_dma_mark_swiotlb - Mark the scatterlist for SWIOTLB bouncing |
| 344 | * @sg: SG entry |
| 345 | * |
| 346 | * Description: |
| 347 | * Marks a a scatterlist for SWIOTLB bounce. Not all SG entries may be |
| 348 | * bounced. |
| 349 | */ |
| 350 | static inline void sg_dma_mark_swiotlb(struct scatterlist *sg) |
| 351 | { |
| 352 | sg->dma_flags |= SG_DMA_SWIOTLB; |
| 353 | } |
| 354 | |
| 355 | #else |
| 356 | |
| 357 | static inline bool sg_dma_is_bus_address(struct scatterlist *sg) |
| 358 | { |
| 359 | return false; |
| 360 | } |
| 361 | static inline void sg_dma_mark_bus_address(struct scatterlist *sg) |
| 362 | { |
| 363 | } |
| 364 | static inline void sg_dma_unmark_bus_address(struct scatterlist *sg) |
| 365 | { |
| 366 | } |
| 367 | static inline bool sg_dma_is_swiotlb(struct scatterlist *sg) |
| 368 | { |
| 369 | return false; |
| 370 | } |
| 371 | static inline void sg_dma_mark_swiotlb(struct scatterlist *sg) |
| 372 | { |
| 373 | } |
| 374 | |
| 375 | #endif /* CONFIG_NEED_SG_DMA_FLAGS */ |
| 376 | |
| 377 | /** |
| 378 | * sg_phys - Return physical address of an sg entry |
| 379 | * @sg: SG entry |
| 380 | * |
| 381 | * Description: |
| 382 | * This calls page_to_phys() on the page in this sg entry, and adds the |
| 383 | * sg offset. The caller must know that it is legal to call page_to_phys() |
| 384 | * on the sg page. |
| 385 | * |
| 386 | **/ |
| 387 | static inline dma_addr_t sg_phys(struct scatterlist *sg) |
| 388 | { |
| 389 | return page_to_phys(sg_page(sg)) + sg->offset; |
| 390 | } |
| 391 | |
| 392 | /** |
| 393 | * sg_virt - Return virtual address of an sg entry |
| 394 | * @sg: SG entry |
| 395 | * |
| 396 | * Description: |
| 397 | * This calls page_address() on the page in this sg entry, and adds the |
| 398 | * sg offset. The caller must know that the sg page has a valid virtual |
| 399 | * mapping. |
| 400 | * |
| 401 | **/ |
| 402 | static inline void *sg_virt(struct scatterlist *sg) |
| 403 | { |
| 404 | return page_address(sg_page(sg)) + sg->offset; |
| 405 | } |
| 406 | |
| 407 | /** |
| 408 | * sg_init_marker - Initialize markers in sg table |
| 409 | * @sgl: The SG table |
| 410 | * @nents: Number of entries in table |
| 411 | * |
| 412 | **/ |
| 413 | static inline void sg_init_marker(struct scatterlist *sgl, |
| 414 | unsigned int nents) |
| 415 | { |
| 416 | sg_mark_end(&sgl[nents - 1]); |
| 417 | } |
| 418 | |
| 419 | int sg_nents(struct scatterlist *sg); |
| 420 | int sg_nents_for_len(struct scatterlist *sg, u64 len); |
| 421 | struct scatterlist *sg_next(struct scatterlist *); |
| 422 | struct scatterlist *sg_last(struct scatterlist *s, unsigned int); |
| 423 | void sg_init_table(struct scatterlist *, unsigned int); |
| 424 | void sg_init_one(struct scatterlist *, const void *, unsigned int); |
| 425 | int sg_split(struct scatterlist *in, const int in_mapped_nents, |
| 426 | const off_t skip, const int nb_splits, |
| 427 | const size_t *split_sizes, |
| 428 | struct scatterlist **out, int *out_mapped_nents, |
| 429 | gfp_t gfp_mask); |
| 430 | |
| 431 | typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); |
| 432 | typedef void (sg_free_fn)(struct scatterlist *, unsigned int); |
| 433 | |
| 434 | void __sg_free_table(struct sg_table *, unsigned int, unsigned int, |
| 435 | sg_free_fn *, unsigned int); |
| 436 | void sg_free_table(struct sg_table *); |
| 437 | void sg_free_append_table(struct sg_append_table *sgt); |
| 438 | int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, |
| 439 | struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); |
| 440 | int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); |
| 441 | int sg_alloc_append_table_from_pages(struct sg_append_table *sgt, |
| 442 | struct page **pages, unsigned int n_pages, |
| 443 | unsigned int offset, unsigned long size, |
| 444 | unsigned int max_segment, |
| 445 | unsigned int left_pages, gfp_t gfp_mask); |
| 446 | int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages, |
| 447 | unsigned int n_pages, unsigned int offset, |
| 448 | unsigned long size, |
| 449 | unsigned int max_segment, gfp_t gfp_mask); |
| 450 | |
| 451 | /** |
| 452 | * sg_alloc_table_from_pages - Allocate and initialize an sg table from |
| 453 | * an array of pages |
| 454 | * @sgt: The sg table header to use |
| 455 | * @pages: Pointer to an array of page pointers |
| 456 | * @n_pages: Number of pages in the pages array |
| 457 | * @offset: Offset from start of the first page to the start of a buffer |
| 458 | * @size: Number of valid bytes in the buffer (after offset) |
| 459 | * @gfp_mask: GFP allocation mask |
| 460 | * |
| 461 | * Description: |
| 462 | * Allocate and initialize an sg table from a list of pages. Contiguous |
| 463 | * ranges of the pages are squashed into a single scatterlist node. A user |
| 464 | * may provide an offset at a start and a size of valid data in a buffer |
| 465 | * specified by the page array. The returned sg table is released by |
| 466 | * sg_free_table. |
| 467 | * |
| 468 | * Returns: |
| 469 | * 0 on success, negative error on failure |
| 470 | */ |
| 471 | static inline int sg_alloc_table_from_pages(struct sg_table *sgt, |
| 472 | struct page **pages, |
| 473 | unsigned int n_pages, |
| 474 | unsigned int offset, |
| 475 | unsigned long size, gfp_t gfp_mask) |
| 476 | { |
| 477 | return sg_alloc_table_from_pages_segment(sgt, pages, n_pages, offset, |
| 478 | size, UINT_MAX, gfp_mask); |
| 479 | } |
| 480 | |
| 481 | #ifdef CONFIG_SGL_ALLOC |
| 482 | struct scatterlist *sgl_alloc_order(unsigned long long length, |
| 483 | unsigned int order, bool chainable, |
| 484 | gfp_t gfp, unsigned int *nent_p); |
| 485 | struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, |
| 486 | unsigned int *nent_p); |
| 487 | void sgl_free_n_order(struct scatterlist *sgl, int nents, int order); |
| 488 | void sgl_free_order(struct scatterlist *sgl, int order); |
| 489 | void sgl_free(struct scatterlist *sgl); |
| 490 | #endif /* CONFIG_SGL_ALLOC */ |
| 491 | |
| 492 | size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, |
| 493 | size_t buflen, off_t skip, bool to_buffer); |
| 494 | |
| 495 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
| 496 | const void *buf, size_t buflen); |
| 497 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
| 498 | void *buf, size_t buflen); |
| 499 | |
| 500 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
| 501 | const void *buf, size_t buflen, off_t skip); |
| 502 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
| 503 | void *buf, size_t buflen, off_t skip); |
| 504 | size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, |
| 505 | size_t buflen, off_t skip); |
| 506 | |
| 507 | /* |
| 508 | * Maximum number of entries that will be allocated in one piece, if |
| 509 | * a list larger than this is required then chaining will be utilized. |
| 510 | */ |
| 511 | #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) |
| 512 | |
| 513 | /* |
| 514 | * The maximum number of SG segments that we will put inside a |
| 515 | * scatterlist (unless chaining is used). Should ideally fit inside a |
| 516 | * single page, to avoid a higher order allocation. We could define this |
| 517 | * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The |
| 518 | * minimum value is 32 |
| 519 | */ |
| 520 | #define SG_CHUNK_SIZE 128 |
| 521 | |
| 522 | /* |
| 523 | * Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit |
| 524 | * is totally arbitrary, a setting of 2048 will get you at least 8mb ios. |
| 525 | */ |
| 526 | #ifdef CONFIG_ARCH_NO_SG_CHAIN |
| 527 | #define SG_MAX_SEGMENTS SG_CHUNK_SIZE |
| 528 | #else |
| 529 | #define SG_MAX_SEGMENTS 2048 |
| 530 | #endif |
| 531 | |
| 532 | #ifdef CONFIG_SG_POOL |
| 533 | void sg_free_table_chained(struct sg_table *table, |
| 534 | unsigned nents_first_chunk); |
| 535 | int sg_alloc_table_chained(struct sg_table *table, int nents, |
| 536 | struct scatterlist *first_chunk, |
| 537 | unsigned nents_first_chunk); |
| 538 | #endif |
| 539 | |
| 540 | /* |
| 541 | * sg page iterator |
| 542 | * |
| 543 | * Iterates over sg entries page-by-page. On each successful iteration, you |
| 544 | * can call sg_page_iter_page(@piter) to get the current page. |
| 545 | * @piter->sg will point to the sg holding this page and @piter->sg_pgoffset to |
| 546 | * the page's page offset within the sg. The iteration will stop either when a |
| 547 | * maximum number of sg entries was reached or a terminating sg |
| 548 | * (sg_last(sg) == true) was reached. |
| 549 | */ |
| 550 | struct sg_page_iter { |
| 551 | struct scatterlist *sg; /* sg holding the page */ |
| 552 | unsigned int sg_pgoffset; /* page offset within the sg */ |
| 553 | |
| 554 | /* these are internal states, keep away */ |
| 555 | unsigned int __nents; /* remaining sg entries */ |
| 556 | int __pg_advance; /* nr pages to advance at the |
| 557 | * next step */ |
| 558 | }; |
| 559 | |
| 560 | /* |
| 561 | * sg page iterator for DMA addresses |
| 562 | * |
| 563 | * This is the same as sg_page_iter however you can call |
| 564 | * sg_page_iter_dma_address(@dma_iter) to get the page's DMA |
| 565 | * address. sg_page_iter_page() cannot be called on this iterator. |
| 566 | */ |
| 567 | struct sg_dma_page_iter { |
| 568 | struct sg_page_iter base; |
| 569 | }; |
| 570 | |
| 571 | bool __sg_page_iter_next(struct sg_page_iter *piter); |
| 572 | bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter); |
| 573 | void __sg_page_iter_start(struct sg_page_iter *piter, |
| 574 | struct scatterlist *sglist, unsigned int nents, |
| 575 | unsigned long pgoffset); |
| 576 | /** |
| 577 | * sg_page_iter_page - get the current page held by the page iterator |
| 578 | * @piter: page iterator holding the page |
| 579 | */ |
| 580 | static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) |
| 581 | { |
| 582 | return nth_page(sg_page(piter->sg), piter->sg_pgoffset); |
| 583 | } |
| 584 | |
| 585 | /** |
| 586 | * sg_page_iter_dma_address - get the dma address of the current page held by |
| 587 | * the page iterator. |
| 588 | * @dma_iter: page iterator holding the page |
| 589 | */ |
| 590 | static inline dma_addr_t |
| 591 | sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter) |
| 592 | { |
| 593 | return sg_dma_address(dma_iter->base.sg) + |
| 594 | (dma_iter->base.sg_pgoffset << PAGE_SHIFT); |
| 595 | } |
| 596 | |
| 597 | /** |
| 598 | * for_each_sg_page - iterate over the pages of the given sg list |
| 599 | * @sglist: sglist to iterate over |
| 600 | * @piter: page iterator to hold current page, sg, sg_pgoffset |
| 601 | * @nents: maximum number of sg entries to iterate over |
| 602 | * @pgoffset: starting page offset (in pages) |
| 603 | * |
| 604 | * Callers may use sg_page_iter_page() to get each page pointer. |
| 605 | * In each loop it operates on PAGE_SIZE unit. |
| 606 | */ |
| 607 | #define for_each_sg_page(sglist, piter, nents, pgoffset) \ |
| 608 | for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ |
| 609 | __sg_page_iter_next(piter);) |
| 610 | |
| 611 | /** |
| 612 | * for_each_sg_dma_page - iterate over the pages of the given sg list |
| 613 | * @sglist: sglist to iterate over |
| 614 | * @dma_iter: DMA page iterator to hold current page |
| 615 | * @dma_nents: maximum number of sg entries to iterate over, this is the value |
| 616 | * returned from dma_map_sg |
| 617 | * @pgoffset: starting page offset (in pages) |
| 618 | * |
| 619 | * Callers may use sg_page_iter_dma_address() to get each page's DMA address. |
| 620 | * In each loop it operates on PAGE_SIZE unit. |
| 621 | */ |
| 622 | #define for_each_sg_dma_page(sglist, dma_iter, dma_nents, pgoffset) \ |
| 623 | for (__sg_page_iter_start(&(dma_iter)->base, sglist, dma_nents, \ |
| 624 | pgoffset); \ |
| 625 | __sg_page_iter_dma_next(dma_iter);) |
| 626 | |
| 627 | /** |
| 628 | * for_each_sgtable_page - iterate over all pages in the sg_table object |
| 629 | * @sgt: sg_table object to iterate over |
| 630 | * @piter: page iterator to hold current page |
| 631 | * @pgoffset: starting page offset (in pages) |
| 632 | * |
| 633 | * Iterates over the all memory pages in the buffer described by |
| 634 | * a scatterlist stored in the given sg_table object. |
| 635 | * See also for_each_sg_page(). In each loop it operates on PAGE_SIZE unit. |
| 636 | */ |
| 637 | #define for_each_sgtable_page(sgt, piter, pgoffset) \ |
| 638 | for_each_sg_page((sgt)->sgl, piter, (sgt)->orig_nents, pgoffset) |
| 639 | |
| 640 | /** |
| 641 | * for_each_sgtable_dma_page - iterate over the DMA mapped sg_table object |
| 642 | * @sgt: sg_table object to iterate over |
| 643 | * @dma_iter: DMA page iterator to hold current page |
| 644 | * @pgoffset: starting page offset (in pages) |
| 645 | * |
| 646 | * Iterates over the all DMA mapped pages in the buffer described by |
| 647 | * a scatterlist stored in the given sg_table object. |
| 648 | * See also for_each_sg_dma_page(). In each loop it operates on PAGE_SIZE |
| 649 | * unit. |
| 650 | */ |
| 651 | #define for_each_sgtable_dma_page(sgt, dma_iter, pgoffset) \ |
| 652 | for_each_sg_dma_page((sgt)->sgl, dma_iter, (sgt)->nents, pgoffset) |
| 653 | |
| 654 | |
| 655 | /* |
| 656 | * Mapping sg iterator |
| 657 | * |
| 658 | * Iterates over sg entries mapping page-by-page. On each successful |
| 659 | * iteration, @miter->page points to the mapped page and |
| 660 | * @miter->length bytes of data can be accessed at @miter->addr. As |
| 661 | * long as an iteration is enclosed between start and stop, the user |
| 662 | * is free to choose control structure and when to stop. |
| 663 | * |
| 664 | * @miter->consumed is set to @miter->length on each iteration. It |
| 665 | * can be adjusted if the user can't consume all the bytes in one go. |
| 666 | * Also, a stopped iteration can be resumed by calling next on it. |
| 667 | * This is useful when iteration needs to release all resources and |
| 668 | * continue later (e.g. at the next interrupt). |
| 669 | */ |
| 670 | |
| 671 | #define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ |
| 672 | #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
| 673 | #define SG_MITER_FROM_SG (1 << 2) /* nop */ |
| 674 | |
| 675 | struct sg_mapping_iter { |
| 676 | /* the following three fields can be accessed directly */ |
| 677 | struct page *page; /* currently mapped page */ |
| 678 | void *addr; /* pointer to the mapped area */ |
| 679 | size_t length; /* length of the mapped area */ |
| 680 | size_t consumed; /* number of consumed bytes */ |
| 681 | struct sg_page_iter piter; /* page iterator */ |
| 682 | |
| 683 | /* these are internal states, keep away */ |
| 684 | unsigned int __offset; /* offset within page */ |
| 685 | unsigned int __remaining; /* remaining bytes on page */ |
| 686 | unsigned int __flags; |
| 687 | }; |
| 688 | |
| 689 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, |
| 690 | unsigned int nents, unsigned int flags); |
| 691 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
| 692 | bool sg_miter_next(struct sg_mapping_iter *miter); |
| 693 | void sg_miter_stop(struct sg_mapping_iter *miter); |
| 694 | |
| 695 | #endif /* _LINUX_SCATTERLIST_H */ |