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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 CH |
11 | struct scatterlist { |
12 | #ifdef CONFIG_DEBUG_SG | |
13 | unsigned long sg_magic; | |
14 | #endif | |
15 | unsigned long page_link; | |
16 | unsigned int offset; | |
17 | unsigned int length; | |
18 | dma_addr_t dma_address; | |
19 | #ifdef CONFIG_NEED_SG_DMA_LENGTH | |
20 | unsigned int dma_length; | |
21 | #endif | |
22 | }; | |
23 | ||
c125906b TU |
24 | /* |
25 | * Since the above length field is an unsigned int, below we define the maximum | |
26 | * length in bytes that can be stored in one scatterlist entry. | |
27 | */ | |
28 | #define SCATTERLIST_MAX_SEGMENT (UINT_MAX & PAGE_MASK) | |
29 | ||
84be456f CH |
30 | /* |
31 | * These macros should be used after a dma_map_sg call has been done | |
32 | * to get bus addresses of each of the SG entries and their lengths. | |
33 | * You should only work with the number of sg entries dma_map_sg | |
34 | * returns, or alternatively stop on the first sg_dma_len(sg) which | |
35 | * is 0. | |
36 | */ | |
37 | #define sg_dma_address(sg) ((sg)->dma_address) | |
38 | ||
39 | #ifdef CONFIG_NEED_SG_DMA_LENGTH | |
40 | #define sg_dma_len(sg) ((sg)->dma_length) | |
41 | #else | |
42 | #define sg_dma_len(sg) ((sg)->length) | |
43 | #endif | |
44 | ||
0db9299f JA |
45 | struct sg_table { |
46 | struct scatterlist *sgl; /* the list */ | |
47 | unsigned int nents; /* number of mapped entries */ | |
48 | unsigned int orig_nents; /* original size of list */ | |
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 | |
d6ec0842 | 67 | #define SG_MAGIC 0x87654321 |
723fbf56 AK |
68 | #define SG_CHAIN 0x01UL |
69 | #define SG_END 0x02UL | |
d6ec0842 | 70 | |
645a8d94 TH |
71 | /* |
72 | * We overload the LSB of the page pointer to indicate whether it's | |
73 | * a valid sg entry, or whether it points to the start of a new scatterlist. | |
74 | * Those low bits are there for everyone! (thanks mason :-) | |
75 | */ | |
723fbf56 AK |
76 | #define sg_is_chain(sg) ((sg)->page_link & SG_CHAIN) |
77 | #define sg_is_last(sg) ((sg)->page_link & SG_END) | |
645a8d94 | 78 | #define sg_chain_ptr(sg) \ |
723fbf56 | 79 | ((struct scatterlist *) ((sg)->page_link & ~(SG_CHAIN | SG_END))) |
645a8d94 | 80 | |
82f66fbe | 81 | /** |
642f1490 JA |
82 | * sg_assign_page - Assign a given page to an SG entry |
83 | * @sg: SG entry | |
84 | * @page: The page | |
82f66fbe JA |
85 | * |
86 | * Description: | |
642f1490 JA |
87 | * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
88 | * variant. | |
82f66fbe JA |
89 | * |
90 | **/ | |
642f1490 | 91 | static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
82f66fbe | 92 | { |
723fbf56 | 93 | unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END); |
18dabf47 | 94 | |
de26103d JA |
95 | /* |
96 | * In order for the low bit stealing approach to work, pages | |
97 | * must be aligned at a 32-bit boundary as a minimum. | |
98 | */ | |
723fbf56 | 99 | BUG_ON((unsigned long) page & (SG_CHAIN | SG_END)); |
d6ec0842 JA |
100 | #ifdef CONFIG_DEBUG_SG |
101 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
645a8d94 | 102 | BUG_ON(sg_is_chain(sg)); |
d6ec0842 | 103 | #endif |
18dabf47 | 104 | sg->page_link = page_link | (unsigned long) page; |
82f66fbe JA |
105 | } |
106 | ||
642f1490 JA |
107 | /** |
108 | * sg_set_page - Set sg entry to point at given page | |
109 | * @sg: SG entry | |
110 | * @page: The page | |
111 | * @len: Length of data | |
112 | * @offset: Offset into page | |
113 | * | |
114 | * Description: | |
115 | * Use this function to set an sg entry pointing at a page, never assign | |
116 | * the page directly. We encode sg table information in the lower bits | |
117 | * of the page pointer. See sg_page() for looking up the page belonging | |
118 | * to an sg entry. | |
119 | * | |
120 | **/ | |
121 | static inline void sg_set_page(struct scatterlist *sg, struct page *page, | |
122 | unsigned int len, unsigned int offset) | |
123 | { | |
124 | sg_assign_page(sg, page); | |
125 | sg->offset = offset; | |
126 | sg->length = len; | |
127 | } | |
128 | ||
645a8d94 TH |
129 | static inline struct page *sg_page(struct scatterlist *sg) |
130 | { | |
131 | #ifdef CONFIG_DEBUG_SG | |
132 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
133 | BUG_ON(sg_is_chain(sg)); | |
134 | #endif | |
723fbf56 | 135 | return (struct page *)((sg)->page_link & ~(SG_CHAIN | SG_END)); |
645a8d94 | 136 | } |
82f66fbe | 137 | |
18dabf47 JA |
138 | /** |
139 | * sg_set_buf - Set sg entry to point at given data | |
140 | * @sg: SG entry | |
141 | * @buf: Data | |
142 | * @buflen: Data length | |
143 | * | |
144 | **/ | |
03fd9cee | 145 | static inline void sg_set_buf(struct scatterlist *sg, const void *buf, |
d32311fe HX |
146 | unsigned int buflen) |
147 | { | |
ac4e97ab RR |
148 | #ifdef CONFIG_DEBUG_SG |
149 | BUG_ON(!virt_addr_valid(buf)); | |
150 | #endif | |
642f1490 | 151 | sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); |
1da177e4 LT |
152 | } |
153 | ||
96b418c9 JA |
154 | /* |
155 | * Loop over each sg element, following the pointer to a new list if necessary | |
156 | */ | |
157 | #define for_each_sg(sglist, sg, nr, __i) \ | |
158 | for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) | |
159 | ||
70eb8040 JA |
160 | /** |
161 | * sg_chain - Chain two sglists together | |
162 | * @prv: First scatterlist | |
163 | * @prv_nents: Number of entries in prv | |
164 | * @sgl: Second scatterlist | |
165 | * | |
18dabf47 JA |
166 | * Description: |
167 | * Links @prv@ and @sgl@ together, to form a longer scatterlist. | |
70eb8040 | 168 | * |
18dabf47 | 169 | **/ |
70eb8040 JA |
170 | static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
171 | struct scatterlist *sgl) | |
172 | { | |
645a8d94 TH |
173 | /* |
174 | * offset and length are unused for chain entry. Clear them. | |
175 | */ | |
b801a1e7 RR |
176 | prv[prv_nents - 1].offset = 0; |
177 | prv[prv_nents - 1].length = 0; | |
645a8d94 | 178 | |
73fd546a JA |
179 | /* |
180 | * Set lowest bit to indicate a link pointer, and make sure to clear | |
181 | * the termination bit if it happens to be set. | |
182 | */ | |
723fbf56 AK |
183 | prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN) |
184 | & ~SG_END; | |
70eb8040 JA |
185 | } |
186 | ||
82f66fbe JA |
187 | /** |
188 | * sg_mark_end - Mark the end of the scatterlist | |
c46f2334 | 189 | * @sg: SG entryScatterlist |
82f66fbe JA |
190 | * |
191 | * Description: | |
c46f2334 JA |
192 | * Marks the passed in sg entry as the termination point for the sg |
193 | * table. A call to sg_next() on this entry will return NULL. | |
82f66fbe JA |
194 | * |
195 | **/ | |
c46f2334 | 196 | static inline void sg_mark_end(struct scatterlist *sg) |
82f66fbe | 197 | { |
c46f2334 JA |
198 | #ifdef CONFIG_DEBUG_SG |
199 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
200 | #endif | |
201 | /* | |
202 | * Set termination bit, clear potential chain bit | |
203 | */ | |
723fbf56 AK |
204 | sg->page_link |= SG_END; |
205 | sg->page_link &= ~SG_CHAIN; | |
82f66fbe JA |
206 | } |
207 | ||
c8164d89 PB |
208 | /** |
209 | * sg_unmark_end - Undo setting the end of the scatterlist | |
210 | * @sg: SG entryScatterlist | |
211 | * | |
212 | * Description: | |
213 | * Removes the termination marker from the given entry of the scatterlist. | |
214 | * | |
215 | **/ | |
216 | static inline void sg_unmark_end(struct scatterlist *sg) | |
217 | { | |
218 | #ifdef CONFIG_DEBUG_SG | |
219 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
220 | #endif | |
723fbf56 | 221 | sg->page_link &= ~SG_END; |
c8164d89 PB |
222 | } |
223 | ||
82f66fbe JA |
224 | /** |
225 | * sg_phys - Return physical address of an sg entry | |
226 | * @sg: SG entry | |
227 | * | |
228 | * Description: | |
229 | * This calls page_to_phys() on the page in this sg entry, and adds the | |
230 | * sg offset. The caller must know that it is legal to call page_to_phys() | |
231 | * on the sg page. | |
232 | * | |
233 | **/ | |
85cdffcd | 234 | static inline dma_addr_t sg_phys(struct scatterlist *sg) |
82f66fbe JA |
235 | { |
236 | return page_to_phys(sg_page(sg)) + sg->offset; | |
237 | } | |
238 | ||
239 | /** | |
240 | * sg_virt - Return virtual address of an sg entry | |
18dabf47 | 241 | * @sg: SG entry |
82f66fbe JA |
242 | * |
243 | * Description: | |
244 | * This calls page_address() on the page in this sg entry, and adds the | |
245 | * sg offset. The caller must know that the sg page has a valid virtual | |
246 | * mapping. | |
247 | * | |
248 | **/ | |
249 | static inline void *sg_virt(struct scatterlist *sg) | |
250 | { | |
251 | return page_address(sg_page(sg)) + sg->offset; | |
252 | } | |
253 | ||
f3851786 PB |
254 | /** |
255 | * sg_init_marker - Initialize markers in sg table | |
256 | * @sgl: The SG table | |
257 | * @nents: Number of entries in table | |
258 | * | |
259 | **/ | |
260 | static inline void sg_init_marker(struct scatterlist *sgl, | |
261 | unsigned int nents) | |
262 | { | |
263 | #ifdef CONFIG_DEBUG_SG | |
264 | unsigned int i; | |
265 | ||
266 | for (i = 0; i < nents; i++) | |
267 | sgl[i].sg_magic = SG_MAGIC; | |
268 | #endif | |
269 | sg_mark_end(&sgl[nents - 1]); | |
270 | } | |
271 | ||
2e484610 | 272 | int sg_nents(struct scatterlist *sg); |
cfaed10d | 273 | int sg_nents_for_len(struct scatterlist *sg, u64 len); |
0db9299f JA |
274 | struct scatterlist *sg_next(struct scatterlist *); |
275 | struct scatterlist *sg_last(struct scatterlist *s, unsigned int); | |
276 | void sg_init_table(struct scatterlist *, unsigned int); | |
277 | void sg_init_one(struct scatterlist *, const void *, unsigned int); | |
f8bcbe62 RJ |
278 | int sg_split(struct scatterlist *in, const int in_mapped_nents, |
279 | const off_t skip, const int nb_splits, | |
280 | const size_t *split_sizes, | |
281 | struct scatterlist **out, int *out_mapped_nents, | |
282 | gfp_t gfp_mask); | |
0db9299f JA |
283 | |
284 | typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); | |
285 | typedef void (sg_free_fn)(struct scatterlist *, unsigned int); | |
286 | ||
c53c6d6a | 287 | void __sg_free_table(struct sg_table *, unsigned int, bool, sg_free_fn *); |
0db9299f | 288 | void sg_free_table(struct sg_table *); |
c53c6d6a CH |
289 | int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, |
290 | struct scatterlist *, gfp_t, sg_alloc_fn *); | |
0db9299f | 291 | int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); |
89d8589c TU |
292 | int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, |
293 | unsigned int n_pages, unsigned int offset, | |
294 | unsigned long size, unsigned int max_segment, | |
295 | gfp_t gfp_mask); | |
296 | int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, | |
297 | unsigned int n_pages, unsigned int offset, | |
298 | unsigned long size, gfp_t gfp_mask); | |
0db9299f | 299 | |
e80a0af4 BVA |
300 | #ifdef CONFIG_SGL_ALLOC |
301 | struct scatterlist *sgl_alloc_order(unsigned long long length, | |
302 | unsigned int order, bool chainable, | |
303 | gfp_t gfp, unsigned int *nent_p); | |
304 | struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, | |
305 | unsigned int *nent_p); | |
8c7a8d1c | 306 | void sgl_free_n_order(struct scatterlist *sgl, int nents, int order); |
e80a0af4 BVA |
307 | void sgl_free_order(struct scatterlist *sgl, int order); |
308 | void sgl_free(struct scatterlist *sgl); | |
309 | #endif /* CONFIG_SGL_ALLOC */ | |
310 | ||
386ecb12 DG |
311 | size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, |
312 | size_t buflen, off_t skip, bool to_buffer); | |
313 | ||
b1adaf65 | 314 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f9 | 315 | const void *buf, size_t buflen); |
b1adaf65 FT |
316 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
317 | void *buf, size_t buflen); | |
318 | ||
df642cea | 319 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f9 | 320 | const void *buf, size_t buflen, off_t skip); |
df642cea AM |
321 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
322 | void *buf, size_t buflen, off_t skip); | |
0945e569 JT |
323 | size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, |
324 | size_t buflen, off_t skip); | |
df642cea | 325 | |
0db9299f JA |
326 | /* |
327 | * Maximum number of entries that will be allocated in one piece, if | |
328 | * a list larger than this is required then chaining will be utilized. | |
329 | */ | |
330 | #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) | |
331 | ||
9b1d6c89 ML |
332 | /* |
333 | * The maximum number of SG segments that we will put inside a | |
334 | * scatterlist (unless chaining is used). Should ideally fit inside a | |
335 | * single page, to avoid a higher order allocation. We could define this | |
336 | * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The | |
337 | * minimum value is 32 | |
338 | */ | |
339 | #define SG_CHUNK_SIZE 128 | |
340 | ||
341 | /* | |
342 | * Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit | |
343 | * is totally arbitrary, a setting of 2048 will get you at least 8mb ios. | |
344 | */ | |
345 | #ifdef CONFIG_ARCH_HAS_SG_CHAIN | |
346 | #define SG_MAX_SEGMENTS 2048 | |
347 | #else | |
348 | #define SG_MAX_SEGMENTS SG_CHUNK_SIZE | |
349 | #endif | |
350 | ||
351 | #ifdef CONFIG_SG_POOL | |
352 | void sg_free_table_chained(struct sg_table *table, bool first_chunk); | |
353 | int sg_alloc_table_chained(struct sg_table *table, int nents, | |
354 | struct scatterlist *first_chunk); | |
355 | #endif | |
356 | ||
a321e91b ID |
357 | /* |
358 | * sg page iterator | |
359 | * | |
360 | * Iterates over sg entries page-by-page. On each successful iteration, | |
2db76d7c ID |
361 | * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter) |
362 | * to get the current page and its dma address. @piter->sg will point to the | |
363 | * sg holding this page and @piter->sg_pgoffset to the page's page offset | |
364 | * within the sg. The iteration will stop either when a maximum number of sg | |
365 | * entries was reached or a terminating sg (sg_last(sg) == true) was reached. | |
a321e91b ID |
366 | */ |
367 | struct sg_page_iter { | |
a321e91b ID |
368 | struct scatterlist *sg; /* sg holding the page */ |
369 | unsigned int sg_pgoffset; /* page offset within the sg */ | |
370 | ||
371 | /* these are internal states, keep away */ | |
372 | unsigned int __nents; /* remaining sg entries */ | |
373 | int __pg_advance; /* nr pages to advance at the | |
374 | * next step */ | |
375 | }; | |
376 | ||
377 | bool __sg_page_iter_next(struct sg_page_iter *piter); | |
378 | void __sg_page_iter_start(struct sg_page_iter *piter, | |
379 | struct scatterlist *sglist, unsigned int nents, | |
380 | unsigned long pgoffset); | |
2db76d7c ID |
381 | /** |
382 | * sg_page_iter_page - get the current page held by the page iterator | |
383 | * @piter: page iterator holding the page | |
384 | */ | |
385 | static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) | |
386 | { | |
387 | return nth_page(sg_page(piter->sg), piter->sg_pgoffset); | |
388 | } | |
389 | ||
390 | /** | |
391 | * sg_page_iter_dma_address - get the dma address of the current page held by | |
392 | * the page iterator. | |
393 | * @piter: page iterator holding the page | |
394 | */ | |
395 | static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) | |
396 | { | |
397 | return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT); | |
398 | } | |
a321e91b ID |
399 | |
400 | /** | |
401 | * for_each_sg_page - iterate over the pages of the given sg list | |
402 | * @sglist: sglist to iterate over | |
403 | * @piter: page iterator to hold current page, sg, sg_pgoffset | |
404 | * @nents: maximum number of sg entries to iterate over | |
405 | * @pgoffset: starting page offset | |
406 | */ | |
407 | #define for_each_sg_page(sglist, piter, nents, pgoffset) \ | |
408 | for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ | |
409 | __sg_page_iter_next(piter);) | |
137d3edb TH |
410 | |
411 | /* | |
412 | * Mapping sg iterator | |
413 | * | |
414 | * Iterates over sg entries mapping page-by-page. On each successful | |
415 | * iteration, @miter->page points to the mapped page and | |
416 | * @miter->length bytes of data can be accessed at @miter->addr. As | |
417 | * long as an interation is enclosed between start and stop, the user | |
418 | * is free to choose control structure and when to stop. | |
419 | * | |
420 | * @miter->consumed is set to @miter->length on each iteration. It | |
421 | * can be adjusted if the user can't consume all the bytes in one go. | |
422 | * Also, a stopped iteration can be resumed by calling next on it. | |
423 | * This is useful when iteration needs to release all resources and | |
424 | * continue later (e.g. at the next interrupt). | |
425 | */ | |
426 | ||
427 | #define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ | |
6de7e356 SAS |
428 | #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
429 | #define SG_MITER_FROM_SG (1 << 2) /* nop */ | |
137d3edb TH |
430 | |
431 | struct sg_mapping_iter { | |
432 | /* the following three fields can be accessed directly */ | |
433 | struct page *page; /* currently mapped page */ | |
434 | void *addr; /* pointer to the mapped area */ | |
435 | size_t length; /* length of the mapped area */ | |
436 | size_t consumed; /* number of consumed bytes */ | |
4225fc85 | 437 | struct sg_page_iter piter; /* page iterator */ |
137d3edb TH |
438 | |
439 | /* these are internal states, keep away */ | |
4225fc85 ID |
440 | unsigned int __offset; /* offset within page */ |
441 | unsigned int __remaining; /* remaining bytes on page */ | |
137d3edb TH |
442 | unsigned int __flags; |
443 | }; | |
444 | ||
445 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, | |
446 | unsigned int nents, unsigned int flags); | |
0d6077f8 | 447 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
137d3edb TH |
448 | bool sg_miter_next(struct sg_mapping_iter *miter); |
449 | void sg_miter_stop(struct sg_mapping_iter *miter); | |
450 | ||
1da177e4 | 451 | #endif /* _LINUX_SCATTERLIST_H */ |