Commit | Line | Data |
---|---|---|
b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_SCATTERLIST_H |
3 | #define _LINUX_SCATTERLIST_H | |
4 | ||
187f1882 | 5 | #include <linux/string.h> |
84be456f | 6 | #include <linux/types.h> |
187f1882 PG |
7 | #include <linux/bug.h> |
8 | #include <linux/mm.h> | |
18dabf47 JA |
9 | #include <asm/io.h> |
10 | ||
84be456f | 11 | struct scatterlist { |
84be456f CH |
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 | |
af2880ec | 19 | #ifdef CONFIG_NEED_SG_DMA_FLAGS |
42399301 LG |
20 | unsigned int dma_flags; |
21 | #endif | |
84be456f CH |
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 | ||
0db9299f JA |
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 | ||
3e302dbc MG |
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 | ||
18dabf47 JA |
51 | /* |
52 | * Notes on SG table design. | |
53 | * | |
84be456f CH |
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. | |
18dabf47 JA |
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 | */ | |
1da177e4 | 66 | |
723fbf56 AK |
67 | #define SG_CHAIN 0x01UL |
68 | #define SG_END 0x02UL | |
d6ec0842 | 69 | |
645a8d94 TH |
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 | */ | |
f857acfc LG |
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 | } | |
645a8d94 | 96 | |
82f66fbe | 97 | /** |
642f1490 JA |
98 | * sg_assign_page - Assign a given page to an SG entry |
99 | * @sg: SG entry | |
100 | * @page: The page | |
82f66fbe JA |
101 | * |
102 | * Description: | |
642f1490 JA |
103 | * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
104 | * variant. | |
82f66fbe JA |
105 | * |
106 | **/ | |
642f1490 | 107 | static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
82f66fbe | 108 | { |
723fbf56 | 109 | unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END); |
18dabf47 | 110 | |
de26103d JA |
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 | */ | |
f857acfc | 115 | BUG_ON((unsigned long)page & SG_PAGE_LINK_MASK); |
d6ec0842 | 116 | #ifdef CONFIG_DEBUG_SG |
645a8d94 | 117 | BUG_ON(sg_is_chain(sg)); |
d6ec0842 | 118 | #endif |
18dabf47 | 119 | sg->page_link = page_link | (unsigned long) page; |
82f66fbe JA |
120 | } |
121 | ||
642f1490 JA |
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 | ||
bdadc6d8 MWO |
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 | ||
645a8d94 TH |
168 | static inline struct page *sg_page(struct scatterlist *sg) |
169 | { | |
170 | #ifdef CONFIG_DEBUG_SG | |
645a8d94 TH |
171 | BUG_ON(sg_is_chain(sg)); |
172 | #endif | |
f857acfc | 173 | return (struct page *)((sg)->page_link & ~SG_PAGE_LINK_MASK); |
645a8d94 | 174 | } |
82f66fbe | 175 | |
18dabf47 JA |
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 | **/ | |
03fd9cee | 183 | static inline void sg_set_buf(struct scatterlist *sg, const void *buf, |
d32311fe HX |
184 | unsigned int buflen) |
185 | { | |
ac4e97ab RR |
186 | #ifdef CONFIG_DEBUG_SG |
187 | BUG_ON(!virt_addr_valid(buf)); | |
188 | #endif | |
642f1490 | 189 | sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); |
1da177e4 LT |
190 | } |
191 | ||
96b418c9 JA |
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 | ||
709d6d73 MS |
198 | /* |
199 | * Loop over each sg element in the given sg_table object. | |
200 | */ | |
201 | #define for_each_sgtable_sg(sgt, sg, i) \ | |
68d23705 | 202 | for_each_sg((sgt)->sgl, sg, (sgt)->orig_nents, i) |
709d6d73 MS |
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) \ | |
68d23705 | 210 | for_each_sg((sgt)->sgl, sg, (sgt)->nents, i) |
709d6d73 | 211 | |
07da1223 MG |
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 | ||
70eb8040 JA |
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 | * | |
18dabf47 JA |
234 | * Description: |
235 | * Links @prv@ and @sgl@ together, to form a longer scatterlist. | |
70eb8040 | 236 | * |
18dabf47 | 237 | **/ |
70eb8040 JA |
238 | static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
239 | struct scatterlist *sgl) | |
240 | { | |
07da1223 | 241 | __sg_chain(&prv[prv_nents - 1], sgl); |
70eb8040 JA |
242 | } |
243 | ||
82f66fbe JA |
244 | /** |
245 | * sg_mark_end - Mark the end of the scatterlist | |
c46f2334 | 246 | * @sg: SG entryScatterlist |
82f66fbe JA |
247 | * |
248 | * Description: | |
c46f2334 JA |
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. | |
82f66fbe JA |
251 | * |
252 | **/ | |
c46f2334 | 253 | static inline void sg_mark_end(struct scatterlist *sg) |
82f66fbe | 254 | { |
c46f2334 JA |
255 | /* |
256 | * Set termination bit, clear potential chain bit | |
257 | */ | |
723fbf56 AK |
258 | sg->page_link |= SG_END; |
259 | sg->page_link &= ~SG_CHAIN; | |
82f66fbe JA |
260 | } |
261 | ||
c8164d89 PB |
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 | { | |
723fbf56 | 272 | sg->page_link &= ~SG_END; |
c8164d89 PB |
273 | } |
274 | ||
42399301 | 275 | /* |
af2880ec RM |
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 | |
861370f4 CM |
278 | * flags bits to indicate when a specific dma address is a bus address or the |
279 | * buffer may have been bounced via SWIOTLB. | |
42399301 | 280 | */ |
af2880ec | 281 | #ifdef CONFIG_NEED_SG_DMA_FLAGS |
42399301 | 282 | |
861370f4 CM |
283 | #define SG_DMA_BUS_ADDRESS (1 << 0) |
284 | #define SG_DMA_SWIOTLB (1 << 1) | |
42399301 LG |
285 | |
286 | /** | |
cb147bbe | 287 | * sg_dma_is_bus_address - Return whether a given segment was marked |
42399301 LG |
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 | **/ | |
cb147bbe | 295 | static inline bool sg_dma_is_bus_address(struct scatterlist *sg) |
42399301 LG |
296 | { |
297 | return sg->dma_flags & SG_DMA_BUS_ADDRESS; | |
298 | } | |
299 | ||
300 | /** | |
cb147bbe | 301 | * sg_dma_mark_bus_address - Mark the scatterlist entry as a bus address |
42399301 LG |
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 | ||
861370f4 CM |
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 | ||
42399301 LG |
355 | #else |
356 | ||
cb147bbe | 357 | static inline bool sg_dma_is_bus_address(struct scatterlist *sg) |
42399301 LG |
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 | } | |
861370f4 CM |
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 | } | |
42399301 | 374 | |
af2880ec | 375 | #endif /* CONFIG_NEED_SG_DMA_FLAGS */ |
42399301 | 376 | |
82f66fbe JA |
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 | **/ | |
85cdffcd | 387 | static inline dma_addr_t sg_phys(struct scatterlist *sg) |
82f66fbe JA |
388 | { |
389 | return page_to_phys(sg_page(sg)) + sg->offset; | |
390 | } | |
391 | ||
392 | /** | |
393 | * sg_virt - Return virtual address of an sg entry | |
18dabf47 | 394 | * @sg: SG entry |
82f66fbe JA |
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 | ||
f3851786 PB |
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 | { | |
f3851786 PB |
416 | sg_mark_end(&sgl[nents - 1]); |
417 | } | |
418 | ||
2e484610 | 419 | int sg_nents(struct scatterlist *sg); |
cfaed10d | 420 | int sg_nents_for_len(struct scatterlist *sg, u64 len); |
0db9299f JA |
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); | |
f8bcbe62 RJ |
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); | |
0db9299f JA |
430 | |
431 | typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); | |
432 | typedef void (sg_free_fn)(struct scatterlist *, unsigned int); | |
433 | ||
4635873c | 434 | void __sg_free_table(struct sg_table *, unsigned int, unsigned int, |
3e302dbc | 435 | sg_free_fn *, unsigned int); |
0db9299f | 436 | void sg_free_table(struct sg_table *); |
3e302dbc | 437 | void sg_free_append_table(struct sg_append_table *sgt); |
c53c6d6a | 438 | int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, |
4635873c | 439 | struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); |
0db9299f | 440 | int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); |
3e302dbc MG |
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); | |
90e7a6de MG |
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 | } | |
0db9299f | 480 | |
e80a0af4 BVA |
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); | |
8c7a8d1c | 487 | void sgl_free_n_order(struct scatterlist *sgl, int nents, int order); |
e80a0af4 BVA |
488 | void sgl_free_order(struct scatterlist *sgl, int order); |
489 | void sgl_free(struct scatterlist *sgl); | |
490 | #endif /* CONFIG_SGL_ALLOC */ | |
491 | ||
386ecb12 DG |
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 | ||
b1adaf65 | 495 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f9 | 496 | const void *buf, size_t buflen); |
b1adaf65 FT |
497 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
498 | void *buf, size_t buflen); | |
499 | ||
df642cea | 500 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f9 | 501 | const void *buf, size_t buflen, off_t skip); |
df642cea AM |
502 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
503 | void *buf, size_t buflen, off_t skip); | |
0945e569 JT |
504 | size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, |
505 | size_t buflen, off_t skip); | |
df642cea | 506 | |
0db9299f JA |
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 | ||
9b1d6c89 ML |
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 | */ | |
7c703e54 | 526 | #ifdef CONFIG_ARCH_NO_SG_CHAIN |
9b1d6c89 | 527 | #define SG_MAX_SEGMENTS SG_CHUNK_SIZE |
7c703e54 CH |
528 | #else |
529 | #define SG_MAX_SEGMENTS 2048 | |
9b1d6c89 ML |
530 | #endif |
531 | ||
532 | #ifdef CONFIG_SG_POOL | |
4635873c ML |
533 | void sg_free_table_chained(struct sg_table *table, |
534 | unsigned nents_first_chunk); | |
9b1d6c89 | 535 | int sg_alloc_table_chained(struct sg_table *table, int nents, |
4635873c ML |
536 | struct scatterlist *first_chunk, |
537 | unsigned nents_first_chunk); | |
9b1d6c89 ML |
538 | #endif |
539 | ||
a321e91b ID |
540 | /* |
541 | * sg page iterator | |
542 | * | |
d901b276 | 543 | * Iterates over sg entries page-by-page. On each successful iteration, you |
d2c4ada1 GP |
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. | |
a321e91b ID |
549 | */ |
550 | struct sg_page_iter { | |
a321e91b ID |
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 | ||
d901b276 JG |
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 | ||
a321e91b | 571 | bool __sg_page_iter_next(struct sg_page_iter *piter); |
d901b276 | 572 | bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter); |
a321e91b ID |
573 | void __sg_page_iter_start(struct sg_page_iter *piter, |
574 | struct scatterlist *sglist, unsigned int nents, | |
575 | unsigned long pgoffset); | |
2db76d7c ID |
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. | |
d901b276 | 588 | * @dma_iter: page iterator holding the page |
2db76d7c | 589 | */ |
d901b276 JG |
590 | static inline dma_addr_t |
591 | sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter) | |
2db76d7c | 592 | { |
d901b276 JG |
593 | return sg_dma_address(dma_iter->base.sg) + |
594 | (dma_iter->base.sg_pgoffset << PAGE_SHIFT); | |
2db76d7c | 595 | } |
a321e91b ID |
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 | |
709d6d73 | 602 | * @pgoffset: starting page offset (in pages) |
d901b276 JG |
603 | * |
604 | * Callers may use sg_page_iter_page() to get each page pointer. | |
709d6d73 | 605 | * In each loop it operates on PAGE_SIZE unit. |
a321e91b ID |
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);) | |
137d3edb | 610 | |
d901b276 JG |
611 | /** |
612 | * for_each_sg_dma_page - iterate over the pages of the given sg list | |
613 | * @sglist: sglist to iterate over | |
709d6d73 | 614 | * @dma_iter: DMA page iterator to hold current page |
d901b276 JG |
615 | * @dma_nents: maximum number of sg entries to iterate over, this is the value |
616 | * returned from dma_map_sg | |
709d6d73 | 617 | * @pgoffset: starting page offset (in pages) |
d901b276 JG |
618 | * |
619 | * Callers may use sg_page_iter_dma_address() to get each page's DMA address. | |
709d6d73 | 620 | * In each loop it operates on PAGE_SIZE unit. |
d901b276 JG |
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 | ||
709d6d73 MS |
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) \ | |
68d23705 | 638 | for_each_sg_page((sgt)->sgl, piter, (sgt)->orig_nents, pgoffset) |
709d6d73 MS |
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) \ | |
68d23705 | 652 | for_each_sg_dma_page((sgt)->sgl, dma_iter, (sgt)->nents, pgoffset) |
709d6d73 MS |
653 | |
654 | ||
137d3edb TH |
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 | |
c23c8082 | 661 | * long as an iteration is enclosed between start and stop, the user |
137d3edb TH |
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 */ | |
6de7e356 SAS |
672 | #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
673 | #define SG_MITER_FROM_SG (1 << 2) /* nop */ | |
137d3edb TH |
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 */ | |
4225fc85 | 681 | struct sg_page_iter piter; /* page iterator */ |
137d3edb TH |
682 | |
683 | /* these are internal states, keep away */ | |
4225fc85 ID |
684 | unsigned int __offset; /* offset within page */ |
685 | unsigned int __remaining; /* remaining bytes on page */ | |
137d3edb TH |
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); | |
0d6077f8 | 691 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
137d3edb TH |
692 | bool sg_miter_next(struct sg_mapping_iter *miter); |
693 | void sg_miter_stop(struct sg_mapping_iter *miter); | |
694 | ||
1da177e4 | 695 | #endif /* _LINUX_SCATTERLIST_H */ |