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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
11struct 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};
20
21/*
22 * Since the above length field is an unsigned int, below we define the maximum
23 * length in bytes that can be stored in one scatterlist entry.
24 */
25#define SCATTERLIST_MAX_SEGMENT (UINT_MAX & PAGE_MASK)
26
27/*
28 * These macros should be used after a dma_map_sg call has been done
29 * to get bus addresses of each of the SG entries and their lengths.
30 * You should only work with the number of sg entries dma_map_sg
31 * returns, or alternatively stop on the first sg_dma_len(sg) which
32 * is 0.
33 */
34#define sg_dma_address(sg) ((sg)->dma_address)
35
36#ifdef CONFIG_NEED_SG_DMA_LENGTH
37#define sg_dma_len(sg) ((sg)->dma_length)
38#else
39#define sg_dma_len(sg) ((sg)->length)
40#endif
41
42struct sg_table {
43 struct scatterlist *sgl; /* the list */
44 unsigned int nents; /* number of mapped entries */
45 unsigned int orig_nents; /* original size of list */
46};
47
48/*
49 * Notes on SG table design.
50 *
51 * We use the unsigned long page_link field in the scatterlist struct to place
52 * the page pointer AND encode information about the sg table as well. The two
53 * lower bits are reserved for this information.
54 *
55 * If bit 0 is set, then the page_link contains a pointer to the next sg
56 * table list. Otherwise the next entry is at sg + 1.
57 *
58 * If bit 1 is set, then this sg entry is the last element in a list.
59 *
60 * See sg_next().
61 *
62 */
63
64#define SG_CHAIN 0x01UL
65#define SG_END 0x02UL
66
67/*
68 * We overload the LSB of the page pointer to indicate whether it's
69 * a valid sg entry, or whether it points to the start of a new scatterlist.
70 * Those low bits are there for everyone! (thanks mason :-)
71 */
72#define sg_is_chain(sg) ((sg)->page_link & SG_CHAIN)
73#define sg_is_last(sg) ((sg)->page_link & SG_END)
74#define sg_chain_ptr(sg) \
75 ((struct scatterlist *) ((sg)->page_link & ~(SG_CHAIN | SG_END)))
76
77/**
78 * sg_assign_page - Assign a given page to an SG entry
79 * @sg: SG entry
80 * @page: The page
81 *
82 * Description:
83 * Assign page to sg entry. Also see sg_set_page(), the most commonly used
84 * variant.
85 *
86 **/
87static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
88{
89 unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END);
90
91 /*
92 * In order for the low bit stealing approach to work, pages
93 * must be aligned at a 32-bit boundary as a minimum.
94 */
95 BUG_ON((unsigned long) page & (SG_CHAIN | SG_END));
96#ifdef CONFIG_DEBUG_SG
97 BUG_ON(sg_is_chain(sg));
98#endif
99 sg->page_link = page_link | (unsigned long) page;
100}
101
102/**
103 * sg_set_page - Set sg entry to point at given page
104 * @sg: SG entry
105 * @page: The page
106 * @len: Length of data
107 * @offset: Offset into page
108 *
109 * Description:
110 * Use this function to set an sg entry pointing at a page, never assign
111 * the page directly. We encode sg table information in the lower bits
112 * of the page pointer. See sg_page() for looking up the page belonging
113 * to an sg entry.
114 *
115 **/
116static inline void sg_set_page(struct scatterlist *sg, struct page *page,
117 unsigned int len, unsigned int offset)
118{
119 sg_assign_page(sg, page);
120 sg->offset = offset;
121 sg->length = len;
122}
123
124static inline struct page *sg_page(struct scatterlist *sg)
125{
126#ifdef CONFIG_DEBUG_SG
127 BUG_ON(sg_is_chain(sg));
128#endif
129 return (struct page *)((sg)->page_link & ~(SG_CHAIN | SG_END));
130}
131
132/**
133 * sg_set_buf - Set sg entry to point at given data
134 * @sg: SG entry
135 * @buf: Data
136 * @buflen: Data length
137 *
138 **/
139static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
140 unsigned int buflen)
141{
142#ifdef CONFIG_DEBUG_SG
143 BUG_ON(!virt_addr_valid(buf));
144#endif
145 sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
146}
147
148/*
149 * Loop over each sg element, following the pointer to a new list if necessary
150 */
151#define for_each_sg(sglist, sg, nr, __i) \
152 for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
153
154/*
155 * Loop over each sg element in the given sg_table object.
156 */
157#define for_each_sgtable_sg(sgt, sg, i) \
158 for_each_sg((sgt)->sgl, sg, (sgt)->orig_nents, i)
159
160/*
161 * Loop over each sg element in the given *DMA mapped* sg_table object.
162 * Please use sg_dma_address(sg) and sg_dma_len(sg) to extract DMA addresses
163 * of the each element.
164 */
165#define for_each_sgtable_dma_sg(sgt, sg, i) \
166 for_each_sg((sgt)->sgl, sg, (sgt)->nents, i)
167
168/**
169 * sg_chain - Chain two sglists together
170 * @prv: First scatterlist
171 * @prv_nents: Number of entries in prv
172 * @sgl: Second scatterlist
173 *
174 * Description:
175 * Links @prv@ and @sgl@ together, to form a longer scatterlist.
176 *
177 **/
178static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
179 struct scatterlist *sgl)
180{
181 /*
182 * offset and length are unused for chain entry. Clear them.
183 */
184 prv[prv_nents - 1].offset = 0;
185 prv[prv_nents - 1].length = 0;
186
187 /*
188 * Set lowest bit to indicate a link pointer, and make sure to clear
189 * the termination bit if it happens to be set.
190 */
191 prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN)
192 & ~SG_END;
193}
194
195/**
196 * sg_mark_end - Mark the end of the scatterlist
197 * @sg: SG entryScatterlist
198 *
199 * Description:
200 * Marks the passed in sg entry as the termination point for the sg
201 * table. A call to sg_next() on this entry will return NULL.
202 *
203 **/
204static inline void sg_mark_end(struct scatterlist *sg)
205{
206 /*
207 * Set termination bit, clear potential chain bit
208 */
209 sg->page_link |= SG_END;
210 sg->page_link &= ~SG_CHAIN;
211}
212
213/**
214 * sg_unmark_end - Undo setting the end of the scatterlist
215 * @sg: SG entryScatterlist
216 *
217 * Description:
218 * Removes the termination marker from the given entry of the scatterlist.
219 *
220 **/
221static inline void sg_unmark_end(struct scatterlist *sg)
222{
223 sg->page_link &= ~SG_END;
224}
225
226/**
227 * sg_phys - Return physical address of an sg entry
228 * @sg: SG entry
229 *
230 * Description:
231 * This calls page_to_phys() on the page in this sg entry, and adds the
232 * sg offset. The caller must know that it is legal to call page_to_phys()
233 * on the sg page.
234 *
235 **/
236static inline dma_addr_t sg_phys(struct scatterlist *sg)
237{
238 return page_to_phys(sg_page(sg)) + sg->offset;
239}
240
241/**
242 * sg_virt - Return virtual address of an sg entry
243 * @sg: SG entry
244 *
245 * Description:
246 * This calls page_address() on the page in this sg entry, and adds the
247 * sg offset. The caller must know that the sg page has a valid virtual
248 * mapping.
249 *
250 **/
251static inline void *sg_virt(struct scatterlist *sg)
252{
253 return page_address(sg_page(sg)) + sg->offset;
254}
255
256/**
257 * sg_init_marker - Initialize markers in sg table
258 * @sgl: The SG table
259 * @nents: Number of entries in table
260 *
261 **/
262static inline void sg_init_marker(struct scatterlist *sgl,
263 unsigned int nents)
264{
265 sg_mark_end(&sgl[nents - 1]);
266}
267
268int sg_nents(struct scatterlist *sg);
269int sg_nents_for_len(struct scatterlist *sg, u64 len);
270struct scatterlist *sg_next(struct scatterlist *);
271struct scatterlist *sg_last(struct scatterlist *s, unsigned int);
272void sg_init_table(struct scatterlist *, unsigned int);
273void sg_init_one(struct scatterlist *, const void *, unsigned int);
274int sg_split(struct scatterlist *in, const int in_mapped_nents,
275 const off_t skip, const int nb_splits,
276 const size_t *split_sizes,
277 struct scatterlist **out, int *out_mapped_nents,
278 gfp_t gfp_mask);
279
280typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
281typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
282
283void __sg_free_table(struct sg_table *, unsigned int, unsigned int,
284 sg_free_fn *);
285void sg_free_table(struct sg_table *);
286int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
287 struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *);
288int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
289int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
290 unsigned int n_pages, unsigned int offset,
291 unsigned long size, unsigned int max_segment,
292 gfp_t gfp_mask);
293int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
294 unsigned int n_pages, unsigned int offset,
295 unsigned long size, gfp_t gfp_mask);
296
297#ifdef CONFIG_SGL_ALLOC
298struct scatterlist *sgl_alloc_order(unsigned long long length,
299 unsigned int order, bool chainable,
300 gfp_t gfp, unsigned int *nent_p);
301struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp,
302 unsigned int *nent_p);
303void sgl_free_n_order(struct scatterlist *sgl, int nents, int order);
304void sgl_free_order(struct scatterlist *sgl, int order);
305void sgl_free(struct scatterlist *sgl);
306#endif /* CONFIG_SGL_ALLOC */
307
308size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
309 size_t buflen, off_t skip, bool to_buffer);
310
311size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
312 const void *buf, size_t buflen);
313size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
314 void *buf, size_t buflen);
315
316size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
317 const void *buf, size_t buflen, off_t skip);
318size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
319 void *buf, size_t buflen, off_t skip);
320size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
321 size_t buflen, off_t skip);
322
323/*
324 * Maximum number of entries that will be allocated in one piece, if
325 * a list larger than this is required then chaining will be utilized.
326 */
327#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist))
328
329/*
330 * The maximum number of SG segments that we will put inside a
331 * scatterlist (unless chaining is used). Should ideally fit inside a
332 * single page, to avoid a higher order allocation. We could define this
333 * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The
334 * minimum value is 32
335 */
336#define SG_CHUNK_SIZE 128
337
338/*
339 * Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit
340 * is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
341 */
342#ifdef CONFIG_ARCH_NO_SG_CHAIN
343#define SG_MAX_SEGMENTS SG_CHUNK_SIZE
344#else
345#define SG_MAX_SEGMENTS 2048
346#endif
347
348#ifdef CONFIG_SG_POOL
349void sg_free_table_chained(struct sg_table *table,
350 unsigned nents_first_chunk);
351int sg_alloc_table_chained(struct sg_table *table, int nents,
352 struct scatterlist *first_chunk,
353 unsigned nents_first_chunk);
354#endif
355
356/*
357 * sg page iterator
358 *
359 * Iterates over sg entries page-by-page. On each successful iteration, you
360 * can call sg_page_iter_page(@piter) to get the current page.
361 * @piter->sg will point to the sg holding this page and @piter->sg_pgoffset to
362 * the page's page offset within the sg. The iteration will stop either when a
363 * maximum number of sg entries was reached or a terminating sg
364 * (sg_last(sg) == true) was reached.
365 */
366struct sg_page_iter {
367 struct scatterlist *sg; /* sg holding the page */
368 unsigned int sg_pgoffset; /* page offset within the sg */
369
370 /* these are internal states, keep away */
371 unsigned int __nents; /* remaining sg entries */
372 int __pg_advance; /* nr pages to advance at the
373 * next step */
374};
375
376/*
377 * sg page iterator for DMA addresses
378 *
379 * This is the same as sg_page_iter however you can call
380 * sg_page_iter_dma_address(@dma_iter) to get the page's DMA
381 * address. sg_page_iter_page() cannot be called on this iterator.
382 */
383struct sg_dma_page_iter {
384 struct sg_page_iter base;
385};
386
387bool __sg_page_iter_next(struct sg_page_iter *piter);
388bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter);
389void __sg_page_iter_start(struct sg_page_iter *piter,
390 struct scatterlist *sglist, unsigned int nents,
391 unsigned long pgoffset);
392/**
393 * sg_page_iter_page - get the current page held by the page iterator
394 * @piter: page iterator holding the page
395 */
396static inline struct page *sg_page_iter_page(struct sg_page_iter *piter)
397{
398 return nth_page(sg_page(piter->sg), piter->sg_pgoffset);
399}
400
401/**
402 * sg_page_iter_dma_address - get the dma address of the current page held by
403 * the page iterator.
404 * @dma_iter: page iterator holding the page
405 */
406static inline dma_addr_t
407sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter)
408{
409 return sg_dma_address(dma_iter->base.sg) +
410 (dma_iter->base.sg_pgoffset << PAGE_SHIFT);
411}
412
413/**
414 * for_each_sg_page - iterate over the pages of the given sg list
415 * @sglist: sglist to iterate over
416 * @piter: page iterator to hold current page, sg, sg_pgoffset
417 * @nents: maximum number of sg entries to iterate over
418 * @pgoffset: starting page offset (in pages)
419 *
420 * Callers may use sg_page_iter_page() to get each page pointer.
421 * In each loop it operates on PAGE_SIZE unit.
422 */
423#define for_each_sg_page(sglist, piter, nents, pgoffset) \
424 for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \
425 __sg_page_iter_next(piter);)
426
427/**
428 * for_each_sg_dma_page - iterate over the pages of the given sg list
429 * @sglist: sglist to iterate over
430 * @dma_iter: DMA page iterator to hold current page
431 * @dma_nents: maximum number of sg entries to iterate over, this is the value
432 * returned from dma_map_sg
433 * @pgoffset: starting page offset (in pages)
434 *
435 * Callers may use sg_page_iter_dma_address() to get each page's DMA address.
436 * In each loop it operates on PAGE_SIZE unit.
437 */
438#define for_each_sg_dma_page(sglist, dma_iter, dma_nents, pgoffset) \
439 for (__sg_page_iter_start(&(dma_iter)->base, sglist, dma_nents, \
440 pgoffset); \
441 __sg_page_iter_dma_next(dma_iter);)
442
443/**
444 * for_each_sgtable_page - iterate over all pages in the sg_table object
445 * @sgt: sg_table object to iterate over
446 * @piter: page iterator to hold current page
447 * @pgoffset: starting page offset (in pages)
448 *
449 * Iterates over the all memory pages in the buffer described by
450 * a scatterlist stored in the given sg_table object.
451 * See also for_each_sg_page(). In each loop it operates on PAGE_SIZE unit.
452 */
453#define for_each_sgtable_page(sgt, piter, pgoffset) \
454 for_each_sg_page((sgt)->sgl, piter, (sgt)->orig_nents, pgoffset)
455
456/**
457 * for_each_sgtable_dma_page - iterate over the DMA mapped sg_table object
458 * @sgt: sg_table object to iterate over
459 * @dma_iter: DMA page iterator to hold current page
460 * @pgoffset: starting page offset (in pages)
461 *
462 * Iterates over the all DMA mapped pages in the buffer described by
463 * a scatterlist stored in the given sg_table object.
464 * See also for_each_sg_dma_page(). In each loop it operates on PAGE_SIZE
465 * unit.
466 */
467#define for_each_sgtable_dma_page(sgt, dma_iter, pgoffset) \
468 for_each_sg_dma_page((sgt)->sgl, dma_iter, (sgt)->nents, pgoffset)
469
470
471/*
472 * Mapping sg iterator
473 *
474 * Iterates over sg entries mapping page-by-page. On each successful
475 * iteration, @miter->page points to the mapped page and
476 * @miter->length bytes of data can be accessed at @miter->addr. As
477 * long as an interation is enclosed between start and stop, the user
478 * is free to choose control structure and when to stop.
479 *
480 * @miter->consumed is set to @miter->length on each iteration. It
481 * can be adjusted if the user can't consume all the bytes in one go.
482 * Also, a stopped iteration can be resumed by calling next on it.
483 * This is useful when iteration needs to release all resources and
484 * continue later (e.g. at the next interrupt).
485 */
486
487#define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */
488#define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */
489#define SG_MITER_FROM_SG (1 << 2) /* nop */
490
491struct sg_mapping_iter {
492 /* the following three fields can be accessed directly */
493 struct page *page; /* currently mapped page */
494 void *addr; /* pointer to the mapped area */
495 size_t length; /* length of the mapped area */
496 size_t consumed; /* number of consumed bytes */
497 struct sg_page_iter piter; /* page iterator */
498
499 /* these are internal states, keep away */
500 unsigned int __offset; /* offset within page */
501 unsigned int __remaining; /* remaining bytes on page */
502 unsigned int __flags;
503};
504
505void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
506 unsigned int nents, unsigned int flags);
507bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset);
508bool sg_miter_next(struct sg_mapping_iter *miter);
509void sg_miter_stop(struct sg_mapping_iter *miter);
510
511#endif /* _LINUX_SCATTERLIST_H */
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
11struct 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
39struct 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
45struct 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
77static inline unsigned int __sg_flags(struct scatterlist *sg)
78{
79 return sg->page_link & SG_PAGE_LINK_MASK;
80}
81
82static inline struct scatterlist *sg_chain_ptr(struct scatterlist *sg)
83{
84 return (struct scatterlist *)(sg->page_link & ~SG_PAGE_LINK_MASK);
85}
86
87static inline bool sg_is_chain(struct scatterlist *sg)
88{
89 return __sg_flags(sg) & SG_CHAIN;
90}
91
92static 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 **/
107static 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 **/
136static 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 **/
158static 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
168static 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 **/
183static 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
212static 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 **/
238static 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 **/
253static 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 **/
270static inline void sg_unmark_end(struct scatterlist *sg)
271{
272 sg->page_link &= ~SG_END;
273}
274
275/*
276 * On 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 **/
295static 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 **/
310static inline void sg_dma_mark_bus_address(struct scatterlist *sg)
311{
312 sg->dma_flags |= SG_DMA_BUS_ADDRESS;
313}
314
315/**
316 * sg_dma_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 **/
322static 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 swiotlb_find_pool().
336 */
337static 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 */
350static inline void sg_dma_mark_swiotlb(struct scatterlist *sg)
351{
352 sg->dma_flags |= SG_DMA_SWIOTLB;
353}
354
355#else
356
357static inline bool sg_dma_is_bus_address(struct scatterlist *sg)
358{
359 return false;
360}
361static inline void sg_dma_mark_bus_address(struct scatterlist *sg)
362{
363}
364static inline void sg_dma_unmark_bus_address(struct scatterlist *sg)
365{
366}
367static inline bool sg_dma_is_swiotlb(struct scatterlist *sg)
368{
369 return false;
370}
371static 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 **/
387static 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 **/
402static 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 **/
413static inline void sg_init_marker(struct scatterlist *sgl,
414 unsigned int nents)
415{
416 sg_mark_end(&sgl[nents - 1]);
417}
418
419int sg_nents(struct scatterlist *sg);
420int sg_nents_for_len(struct scatterlist *sg, u64 len);
421struct scatterlist *sg_next(struct scatterlist *);
422struct scatterlist *sg_last(struct scatterlist *s, unsigned int);
423void sg_init_table(struct scatterlist *, unsigned int);
424void sg_init_one(struct scatterlist *, const void *, unsigned int);
425int 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
431typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
432typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
433
434void __sg_free_table(struct sg_table *, unsigned int, unsigned int,
435 sg_free_fn *, unsigned int);
436void sg_free_table(struct sg_table *);
437void sg_free_append_table(struct sg_append_table *sgt);
438int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
439 struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *);
440int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
441int 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);
446int 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 */
471static 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
482struct scatterlist *sgl_alloc_order(unsigned long long length,
483 unsigned int order, bool chainable,
484 gfp_t gfp, unsigned int *nent_p);
485struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp,
486 unsigned int *nent_p);
487void sgl_free_n_order(struct scatterlist *sgl, int nents, int order);
488void sgl_free_order(struct scatterlist *sgl, int order);
489void sgl_free(struct scatterlist *sgl);
490#endif /* CONFIG_SGL_ALLOC */
491
492size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
493 size_t buflen, off_t skip, bool to_buffer);
494
495size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
496 const void *buf, size_t buflen);
497size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
498 void *buf, size_t buflen);
499
500size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
501 const void *buf, size_t buflen, off_t skip);
502size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
503 void *buf, size_t buflen, off_t skip);
504size_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
533void sg_free_table_chained(struct sg_table *table,
534 unsigned nents_first_chunk);
535int 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 */
550struct 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 */
567struct sg_dma_page_iter {
568 struct sg_page_iter base;
569};
570
571bool __sg_page_iter_next(struct sg_page_iter *piter);
572bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter);
573void __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 */
580static 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 */
590static inline dma_addr_t
591sg_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
675struct 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
689void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
690 unsigned int nents, unsigned int flags);
691bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset);
692bool sg_miter_next(struct sg_mapping_iter *miter);
693void sg_miter_stop(struct sg_mapping_iter *miter);
694
695#endif /* _LINUX_SCATTERLIST_H */