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1 | #ifndef _LINUX_SCATTERLIST_H |
1 | #ifndef _LINUX_SCATTERLIST_H |
2 | #define _LINUX_SCATTERLIST_H |
2 | #define _LINUX_SCATTERLIST_H |
3 | 3 | ||
4 | #include |
4 | #include |
5 | #include |
5 | #include |
6 | #include |
6 | #include |
7 | 7 | ||
8 | #include |
8 | #include |
9 | #include |
9 | #include |
10 | //#include |
10 | //#include |
11 | 11 | ||
12 | struct sg_table { |
12 | struct sg_table { |
13 | struct scatterlist *sgl; /* the list */ |
13 | struct scatterlist *sgl; /* the list */ |
14 | unsigned int nents; /* number of mapped entries */ |
14 | unsigned int nents; /* number of mapped entries */ |
15 | unsigned int orig_nents; /* original size of list */ |
15 | unsigned int orig_nents; /* original size of list */ |
16 | }; |
16 | }; |
17 | 17 | ||
18 | /* |
18 | /* |
19 | * Notes on SG table design. |
19 | * Notes on SG table design. |
20 | * |
20 | * |
21 | * Architectures must provide an unsigned long page_link field in the |
21 | * Architectures must provide an unsigned long page_link field in the |
22 | * scatterlist struct. We use that to place the page pointer AND encode |
22 | * scatterlist struct. We use that to place the page pointer AND encode |
23 | * information about the sg table as well. The two lower bits are reserved |
23 | * information about the sg table as well. The two lower bits are reserved |
24 | * for this information. |
24 | * for this information. |
25 | * |
25 | * |
26 | * If bit 0 is set, then the page_link contains a pointer to the next sg |
26 | * If bit 0 is set, then the page_link contains a pointer to the next sg |
27 | * table list. Otherwise the next entry is at sg + 1. |
27 | * table list. Otherwise the next entry is at sg + 1. |
28 | * |
28 | * |
29 | * If bit 1 is set, then this sg entry is the last element in a list. |
29 | * If bit 1 is set, then this sg entry is the last element in a list. |
30 | * |
30 | * |
31 | * See sg_next(). |
31 | * See sg_next(). |
32 | * |
32 | * |
33 | */ |
33 | */ |
34 | 34 | ||
35 | #define SG_MAGIC 0x87654321 |
35 | #define SG_MAGIC 0x87654321 |
36 | 36 | ||
37 | /* |
37 | /* |
38 | * We overload the LSB of the page pointer to indicate whether it's |
38 | * We overload the LSB of the page pointer to indicate whether it's |
39 | * a valid sg entry, or whether it points to the start of a new scatterlist. |
39 | * a valid sg entry, or whether it points to the start of a new scatterlist. |
40 | * Those low bits are there for everyone! (thanks mason :-) |
40 | * Those low bits are there for everyone! (thanks mason :-) |
41 | */ |
41 | */ |
42 | #define sg_is_chain(sg) ((sg)->page_link & 0x01) |
42 | #define sg_is_chain(sg) ((sg)->page_link & 0x01) |
43 | #define sg_is_last(sg) ((sg)->page_link & 0x02) |
43 | #define sg_is_last(sg) ((sg)->page_link & 0x02) |
44 | #define sg_chain_ptr(sg) \ |
44 | #define sg_chain_ptr(sg) \ |
45 | ((struct scatterlist *) ((sg)->page_link & ~0x03)) |
45 | ((struct scatterlist *) ((sg)->page_link & ~0x03)) |
46 | 46 | ||
47 | /** |
47 | /** |
48 | * sg_assign_page - Assign a given page to an SG entry |
48 | * sg_assign_page - Assign a given page to an SG entry |
49 | * @sg: SG entry |
49 | * @sg: SG entry |
50 | * @page: The page |
50 | * @page: The page |
51 | * |
51 | * |
52 | * Description: |
52 | * Description: |
53 | * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
53 | * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
54 | * variant. |
54 | * variant. |
55 | * |
55 | * |
56 | **/ |
56 | **/ |
57 | static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
57 | static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
58 | { |
58 | { |
59 | unsigned long page_link = sg->page_link & 0x3; |
59 | unsigned long page_link = sg->page_link & 0x3; |
60 | 60 | ||
61 | /* |
61 | /* |
62 | * In order for the low bit stealing approach to work, pages |
62 | * In order for the low bit stealing approach to work, pages |
63 | * must be aligned at a 32-bit boundary as a minimum. |
63 | * must be aligned at a 32-bit boundary as a minimum. |
64 | */ |
64 | */ |
65 | BUG_ON((unsigned long) page & 0x03); |
65 | BUG_ON((unsigned long) page & 0x03); |
66 | #ifdef CONFIG_DEBUG_SG |
66 | #ifdef CONFIG_DEBUG_SG |
67 | BUG_ON(sg->sg_magic != SG_MAGIC); |
67 | BUG_ON(sg->sg_magic != SG_MAGIC); |
68 | BUG_ON(sg_is_chain(sg)); |
68 | BUG_ON(sg_is_chain(sg)); |
69 | #endif |
69 | #endif |
70 | sg->page_link = page_link | (unsigned long) page; |
70 | sg->page_link = page_link | (unsigned long) page; |
71 | } |
71 | } |
72 | 72 | ||
73 | /** |
73 | /** |
74 | * sg_set_page - Set sg entry to point at given page |
74 | * sg_set_page - Set sg entry to point at given page |
75 | * @sg: SG entry |
75 | * @sg: SG entry |
76 | * @page: The page |
76 | * @page: The page |
77 | * @len: Length of data |
77 | * @len: Length of data |
78 | * @offset: Offset into page |
78 | * @offset: Offset into page |
79 | * |
79 | * |
80 | * Description: |
80 | * Description: |
81 | * Use this function to set an sg entry pointing at a page, never assign |
81 | * Use this function to set an sg entry pointing at a page, never assign |
82 | * the page directly. We encode sg table information in the lower bits |
82 | * the page directly. We encode sg table information in the lower bits |
83 | * of the page pointer. See sg_page() for looking up the page belonging |
83 | * of the page pointer. See sg_page() for looking up the page belonging |
84 | * to an sg entry. |
84 | * to an sg entry. |
85 | * |
85 | * |
86 | **/ |
86 | **/ |
87 | static inline void sg_set_page(struct scatterlist *sg, struct page *page, |
87 | static inline void sg_set_page(struct scatterlist *sg, struct page *page, |
88 | unsigned int len, unsigned int offset) |
88 | unsigned int len, unsigned int offset) |
89 | { |
89 | { |
90 | sg_assign_page(sg, page); |
90 | sg_assign_page(sg, page); |
91 | sg->offset = offset; |
91 | sg->offset = offset; |
92 | sg->length = len; |
92 | sg->length = len; |
93 | } |
93 | } |
94 | 94 | ||
95 | static inline struct page *sg_page(struct scatterlist *sg) |
95 | static inline struct page *sg_page(struct scatterlist *sg) |
96 | { |
96 | { |
97 | #ifdef CONFIG_DEBUG_SG |
97 | #ifdef CONFIG_DEBUG_SG |
98 | BUG_ON(sg->sg_magic != SG_MAGIC); |
98 | BUG_ON(sg->sg_magic != SG_MAGIC); |
99 | BUG_ON(sg_is_chain(sg)); |
99 | BUG_ON(sg_is_chain(sg)); |
100 | #endif |
100 | #endif |
101 | return (struct page *)((sg)->page_link & ~0x3); |
101 | return (struct page *)((sg)->page_link & ~0x3); |
102 | } |
102 | } |
- | 103 | ||
- | 104 | /** |
|
- | 105 | * sg_set_buf - Set sg entry to point at given data |
|
- | 106 | * @sg: SG entry |
|
- | 107 | * @buf: Data |
|
- | 108 | * @buflen: Data length |
|
- | 109 | * |
|
- | 110 | **/ |
|
- | 111 | //static inline void sg_set_buf(struct scatterlist *sg, const void *buf, |
|
- | 112 | // unsigned int buflen) |
|
- | 113 | //{ |
|
- | 114 | //#ifdef CONFIG_DEBUG_SG |
|
- | 115 | // BUG_ON(!virt_addr_valid(buf)); |
|
- | 116 | //#endif |
|
- | 117 | // sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); |
|
- | 118 | //} |
|
103 | 119 | ||
104 | /* |
120 | /* |
105 | * Loop over each sg element, following the pointer to a new list if necessary |
121 | * Loop over each sg element, following the pointer to a new list if necessary |
106 | */ |
122 | */ |
107 | #define for_each_sg(sglist, sg, nr, __i) \ |
123 | #define for_each_sg(sglist, sg, nr, __i) \ |
108 | for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) |
124 | for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) |
109 | 125 | ||
110 | /** |
126 | /** |
111 | * sg_chain - Chain two sglists together |
127 | * sg_chain - Chain two sglists together |
112 | * @prv: First scatterlist |
128 | * @prv: First scatterlist |
113 | * @prv_nents: Number of entries in prv |
129 | * @prv_nents: Number of entries in prv |
114 | * @sgl: Second scatterlist |
130 | * @sgl: Second scatterlist |
115 | * |
131 | * |
116 | * Description: |
132 | * Description: |
117 | * Links @prv@ and @sgl@ together, to form a longer scatterlist. |
133 | * Links @prv@ and @sgl@ together, to form a longer scatterlist. |
118 | * |
134 | * |
119 | **/ |
135 | **/ |
120 | static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
136 | static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
121 | struct scatterlist *sgl) |
137 | struct scatterlist *sgl) |
122 | { |
138 | { |
123 | #ifndef ARCH_HAS_SG_CHAIN |
139 | #ifndef CONFIG_ARCH_HAS_SG_CHAIN |
124 | BUG(); |
140 | BUG(); |
125 | #endif |
141 | #endif |
126 | 142 | ||
127 | /* |
143 | /* |
128 | * offset and length are unused for chain entry. Clear them. |
144 | * offset and length are unused for chain entry. Clear them. |
129 | */ |
145 | */ |
130 | prv[prv_nents - 1].offset = 0; |
146 | prv[prv_nents - 1].offset = 0; |
131 | prv[prv_nents - 1].length = 0; |
147 | prv[prv_nents - 1].length = 0; |
132 | 148 | ||
133 | /* |
149 | /* |
134 | * Set lowest bit to indicate a link pointer, and make sure to clear |
150 | * Set lowest bit to indicate a link pointer, and make sure to clear |
135 | * the termination bit if it happens to be set. |
151 | * the termination bit if it happens to be set. |
136 | */ |
152 | */ |
137 | prv[prv_nents - 1].page_link = ((unsigned long) sgl | 0x01) & ~0x02; |
153 | prv[prv_nents - 1].page_link = ((unsigned long) sgl | 0x01) & ~0x02; |
138 | } |
154 | } |
139 | 155 | ||
140 | /** |
156 | /** |
141 | * sg_mark_end - Mark the end of the scatterlist |
157 | * sg_mark_end - Mark the end of the scatterlist |
142 | * @sg: SG entryScatterlist |
158 | * @sg: SG entryScatterlist |
143 | * |
159 | * |
144 | * Description: |
160 | * Description: |
145 | * Marks the passed in sg entry as the termination point for the sg |
161 | * Marks the passed in sg entry as the termination point for the sg |
146 | * table. A call to sg_next() on this entry will return NULL. |
162 | * table. A call to sg_next() on this entry will return NULL. |
147 | * |
163 | * |
148 | **/ |
164 | **/ |
149 | static inline void sg_mark_end(struct scatterlist *sg) |
165 | static inline void sg_mark_end(struct scatterlist *sg) |
150 | { |
166 | { |
151 | #ifdef CONFIG_DEBUG_SG |
167 | #ifdef CONFIG_DEBUG_SG |
152 | BUG_ON(sg->sg_magic != SG_MAGIC); |
168 | BUG_ON(sg->sg_magic != SG_MAGIC); |
153 | #endif |
169 | #endif |
154 | /* |
170 | /* |
155 | * Set termination bit, clear potential chain bit |
171 | * Set termination bit, clear potential chain bit |
156 | */ |
172 | */ |
157 | sg->page_link |= 0x02; |
173 | sg->page_link |= 0x02; |
158 | sg->page_link &= ~0x01; |
174 | sg->page_link &= ~0x01; |
159 | } |
175 | } |
160 | 176 | ||
161 | /** |
177 | /** |
162 | * sg_unmark_end - Undo setting the end of the scatterlist |
178 | * sg_unmark_end - Undo setting the end of the scatterlist |
163 | * @sg: SG entryScatterlist |
179 | * @sg: SG entryScatterlist |
164 | * |
180 | * |
165 | * Description: |
181 | * Description: |
166 | * Removes the termination marker from the given entry of the scatterlist. |
182 | * Removes the termination marker from the given entry of the scatterlist. |
167 | * |
183 | * |
168 | **/ |
184 | **/ |
169 | static inline void sg_unmark_end(struct scatterlist *sg) |
185 | static inline void sg_unmark_end(struct scatterlist *sg) |
170 | { |
186 | { |
171 | #ifdef CONFIG_DEBUG_SG |
187 | #ifdef CONFIG_DEBUG_SG |
172 | BUG_ON(sg->sg_magic != SG_MAGIC); |
188 | BUG_ON(sg->sg_magic != SG_MAGIC); |
173 | #endif |
189 | #endif |
174 | sg->page_link &= ~0x02; |
190 | sg->page_link &= ~0x02; |
175 | } |
191 | } |
176 | 192 | ||
177 | /** |
193 | /** |
178 | * sg_phys - Return physical address of an sg entry |
194 | * sg_phys - Return physical address of an sg entry |
179 | * @sg: SG entry |
195 | * @sg: SG entry |
180 | * |
196 | * |
181 | * Description: |
197 | * Description: |
182 | * This calls page_to_phys() on the page in this sg entry, and adds the |
198 | * This calls page_to_phys() on the page in this sg entry, and adds the |
183 | * sg offset. The caller must know that it is legal to call page_to_phys() |
199 | * sg offset. The caller must know that it is legal to call page_to_phys() |
184 | * on the sg page. |
200 | * on the sg page. |
185 | * |
201 | * |
186 | **/ |
202 | **/ |
187 | static inline dma_addr_t sg_phys(struct scatterlist *sg) |
203 | static inline dma_addr_t sg_phys(struct scatterlist *sg) |
188 | { |
204 | { |
189 | return page_to_phys(sg_page(sg)) + sg->offset; |
205 | return page_to_phys(sg_page(sg)) + sg->offset; |
190 | } |
206 | } |
191 | 207 | ||
192 | /** |
208 | /** |
193 | * sg_virt - Return virtual address of an sg entry |
209 | * sg_virt - Return virtual address of an sg entry |
194 | * @sg: SG entry |
210 | * @sg: SG entry |
195 | * |
211 | * |
196 | * Description: |
212 | * Description: |
197 | * This calls page_address() on the page in this sg entry, and adds the |
213 | * This calls page_address() on the page in this sg entry, and adds the |
198 | * sg offset. The caller must know that the sg page has a valid virtual |
214 | * sg offset. The caller must know that the sg page has a valid virtual |
199 | * mapping. |
215 | * mapping. |
200 | * |
216 | * |
201 | **/ |
217 | **/ |
202 | //static inline void *sg_virt(struct scatterlist *sg) |
218 | //static inline void *sg_virt(struct scatterlist *sg) |
203 | //{ |
219 | //{ |
204 | // return page_address(sg_page(sg)) + sg->offset; |
220 | // return page_address(sg_page(sg)) + sg->offset; |
205 | //} |
221 | //} |
206 | 222 | ||
207 | int sg_nents(struct scatterlist *sg); |
223 | int sg_nents(struct scatterlist *sg); |
208 | struct scatterlist *sg_next(struct scatterlist *); |
224 | struct scatterlist *sg_next(struct scatterlist *); |
209 | struct scatterlist *sg_last(struct scatterlist *s, unsigned int); |
225 | struct scatterlist *sg_last(struct scatterlist *s, unsigned int); |
210 | void sg_init_table(struct scatterlist *, unsigned int); |
226 | void sg_init_table(struct scatterlist *, unsigned int); |
211 | void sg_init_one(struct scatterlist *, const void *, unsigned int); |
227 | void sg_init_one(struct scatterlist *, const void *, unsigned int); |
212 | 228 | ||
213 | typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); |
229 | typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); |
214 | typedef void (sg_free_fn)(struct scatterlist *, unsigned int); |
230 | typedef void (sg_free_fn)(struct scatterlist *, unsigned int); |
215 | 231 | ||
216 | void __sg_free_table(struct sg_table *, unsigned int, bool, sg_free_fn *); |
232 | void __sg_free_table(struct sg_table *, unsigned int, bool, sg_free_fn *); |
217 | void sg_free_table(struct sg_table *); |
233 | void sg_free_table(struct sg_table *); |
218 | int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, |
234 | int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, |
219 | struct scatterlist *, gfp_t, sg_alloc_fn *); |
235 | struct scatterlist *, gfp_t, sg_alloc_fn *); |
220 | int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); |
236 | int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); |
221 | int sg_alloc_table_from_pages(struct sg_table *sgt, |
237 | int sg_alloc_table_from_pages(struct sg_table *sgt, |
222 | struct page **pages, unsigned int n_pages, |
238 | struct page **pages, unsigned int n_pages, |
223 | unsigned long offset, unsigned long size, |
239 | unsigned long offset, unsigned long size, |
224 | gfp_t gfp_mask); |
240 | gfp_t gfp_mask); |
225 | 241 | ||
226 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
242 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
227 | void *buf, size_t buflen); |
243 | void *buf, size_t buflen); |
228 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
244 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
229 | void *buf, size_t buflen); |
245 | void *buf, size_t buflen); |
230 | 246 | ||
231 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
247 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
232 | void *buf, size_t buflen, off_t skip); |
248 | void *buf, size_t buflen, off_t skip); |
233 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
249 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
234 | void *buf, size_t buflen, off_t skip); |
250 | void *buf, size_t buflen, off_t skip); |
235 | 251 | ||
236 | /* |
252 | /* |
237 | * Maximum number of entries that will be allocated in one piece, if |
253 | * Maximum number of entries that will be allocated in one piece, if |
238 | * a list larger than this is required then chaining will be utilized. |
254 | * a list larger than this is required then chaining will be utilized. |
239 | */ |
255 | */ |
240 | #define SG_MAX_SINGLE_ALLOC (4*PAGE_SIZE / sizeof(struct scatterlist)) |
256 | #define SG_MAX_SINGLE_ALLOC (4*PAGE_SIZE / sizeof(struct scatterlist)) |
241 | 257 | ||
242 | /* |
258 | /* |
243 | * sg page iterator |
259 | * sg page iterator |
244 | * |
260 | * |
245 | * Iterates over sg entries page-by-page. On each successful iteration, |
261 | * Iterates over sg entries page-by-page. On each successful iteration, |
246 | * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter) |
262 | * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter) |
247 | * to get the current page and its dma address. @piter->sg will point to the |
263 | * to get the current page and its dma address. @piter->sg will point to the |
248 | * sg holding this page and @piter->sg_pgoffset to the page's page offset |
264 | * sg holding this page and @piter->sg_pgoffset to the page's page offset |
249 | * within the sg. The iteration will stop either when a maximum number of sg |
265 | * within the sg. The iteration will stop either when a maximum number of sg |
250 | * entries was reached or a terminating sg (sg_last(sg) == true) was reached. |
266 | * entries was reached or a terminating sg (sg_last(sg) == true) was reached. |
251 | */ |
267 | */ |
252 | struct sg_page_iter { |
268 | struct sg_page_iter { |
253 | struct scatterlist *sg; /* sg holding the page */ |
269 | struct scatterlist *sg; /* sg holding the page */ |
254 | unsigned int sg_pgoffset; /* page offset within the sg */ |
270 | unsigned int sg_pgoffset; /* page offset within the sg */ |
255 | 271 | ||
256 | /* these are internal states, keep away */ |
272 | /* these are internal states, keep away */ |
257 | unsigned int __nents; /* remaining sg entries */ |
273 | unsigned int __nents; /* remaining sg entries */ |
258 | int __pg_advance; /* nr pages to advance at the |
274 | int __pg_advance; /* nr pages to advance at the |
259 | * next step */ |
275 | * next step */ |
260 | }; |
276 | }; |
261 | 277 | ||
262 | bool __sg_page_iter_next(struct sg_page_iter *piter); |
278 | bool __sg_page_iter_next(struct sg_page_iter *piter); |
263 | void __sg_page_iter_start(struct sg_page_iter *piter, |
279 | void __sg_page_iter_start(struct sg_page_iter *piter, |
264 | struct scatterlist *sglist, unsigned int nents, |
280 | struct scatterlist *sglist, unsigned int nents, |
265 | unsigned long pgoffset); |
281 | unsigned long pgoffset); |
266 | /** |
282 | /** |
267 | * sg_page_iter_page - get the current page held by the page iterator |
283 | * sg_page_iter_page - get the current page held by the page iterator |
268 | * @piter: page iterator holding the page |
284 | * @piter: page iterator holding the page |
269 | */ |
285 | */ |
270 | static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) |
286 | static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) |
271 | { |
287 | { |
272 | return nth_page(sg_page(piter->sg), piter->sg_pgoffset); |
288 | return nth_page(sg_page(piter->sg), piter->sg_pgoffset); |
273 | } |
289 | } |
274 | 290 | ||
275 | /** |
291 | /** |
276 | * sg_page_iter_dma_address - get the dma address of the current page held by |
292 | * sg_page_iter_dma_address - get the dma address of the current page held by |
277 | * the page iterator. |
293 | * the page iterator. |
278 | * @piter: page iterator holding the page |
294 | * @piter: page iterator holding the page |
279 | */ |
295 | */ |
280 | static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) |
296 | static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) |
281 | { |
297 | { |
282 | return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT); |
298 | return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT); |
283 | } |
299 | } |
284 | 300 | ||
285 | /** |
301 | /** |
286 | * for_each_sg_page - iterate over the pages of the given sg list |
302 | * for_each_sg_page - iterate over the pages of the given sg list |
287 | * @sglist: sglist to iterate over |
303 | * @sglist: sglist to iterate over |
288 | * @piter: page iterator to hold current page, sg, sg_pgoffset |
304 | * @piter: page iterator to hold current page, sg, sg_pgoffset |
289 | * @nents: maximum number of sg entries to iterate over |
305 | * @nents: maximum number of sg entries to iterate over |
290 | * @pgoffset: starting page offset |
306 | * @pgoffset: starting page offset |
291 | */ |
307 | */ |
292 | #define for_each_sg_page(sglist, piter, nents, pgoffset) \ |
308 | #define for_each_sg_page(sglist, piter, nents, pgoffset) \ |
293 | for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ |
309 | for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ |
294 | __sg_page_iter_next(piter);) |
310 | __sg_page_iter_next(piter);) |
295 | 311 | ||
296 | /* |
312 | /* |
297 | * Mapping sg iterator |
313 | * Mapping sg iterator |
298 | * |
314 | * |
299 | * Iterates over sg entries mapping page-by-page. On each successful |
315 | * Iterates over sg entries mapping page-by-page. On each successful |
300 | * iteration, @miter->page points to the mapped page and |
316 | * iteration, @miter->page points to the mapped page and |
301 | * @miter->length bytes of data can be accessed at @miter->addr. As |
317 | * @miter->length bytes of data can be accessed at @miter->addr. As |
302 | * long as an interation is enclosed between start and stop, the user |
318 | * long as an interation is enclosed between start and stop, the user |
303 | * is free to choose control structure and when to stop. |
319 | * is free to choose control structure and when to stop. |
304 | * |
320 | * |
305 | * @miter->consumed is set to @miter->length on each iteration. It |
321 | * @miter->consumed is set to @miter->length on each iteration. It |
306 | * can be adjusted if the user can't consume all the bytes in one go. |
322 | * can be adjusted if the user can't consume all the bytes in one go. |
307 | * Also, a stopped iteration can be resumed by calling next on it. |
323 | * Also, a stopped iteration can be resumed by calling next on it. |
308 | * This is useful when iteration needs to release all resources and |
324 | * This is useful when iteration needs to release all resources and |
309 | * continue later (e.g. at the next interrupt). |
325 | * continue later (e.g. at the next interrupt). |
310 | */ |
326 | */ |
311 | 327 | ||
312 | #define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ |
328 | #define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ |
313 | #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
329 | #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
314 | #define SG_MITER_FROM_SG (1 << 2) /* nop */ |
330 | #define SG_MITER_FROM_SG (1 << 2) /* nop */ |
315 | 331 | ||
316 | struct sg_mapping_iter { |
332 | struct sg_mapping_iter { |
317 | /* the following three fields can be accessed directly */ |
333 | /* the following three fields can be accessed directly */ |
318 | struct page *page; /* currently mapped page */ |
334 | struct page *page; /* currently mapped page */ |
319 | void *addr; /* pointer to the mapped area */ |
335 | void *addr; /* pointer to the mapped area */ |
320 | size_t length; /* length of the mapped area */ |
336 | size_t length; /* length of the mapped area */ |
321 | size_t consumed; /* number of consumed bytes */ |
337 | size_t consumed; /* number of consumed bytes */ |
322 | struct sg_page_iter piter; /* page iterator */ |
338 | struct sg_page_iter piter; /* page iterator */ |
323 | 339 | ||
324 | /* these are internal states, keep away */ |
340 | /* these are internal states, keep away */ |
325 | unsigned int __offset; /* offset within page */ |
341 | unsigned int __offset; /* offset within page */ |
326 | unsigned int __remaining; /* remaining bytes on page */ |
342 | unsigned int __remaining; /* remaining bytes on page */ |
327 | unsigned int __flags; |
343 | unsigned int __flags; |
328 | }; |
344 | }; |
329 | 345 | ||
330 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, |
346 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, |
331 | unsigned int nents, unsigned int flags); |
347 | unsigned int nents, unsigned int flags); |
332 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
348 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
333 | bool sg_miter_next(struct sg_mapping_iter *miter); |
349 | bool sg_miter_next(struct sg_mapping_iter *miter); |
334 | void sg_miter_stop(struct sg_mapping_iter *miter); |
350 | void sg_miter_stop(struct sg_mapping_iter *miter); |
335 | 351 | ||
336 | #endif /* _LINUX_SCATTERLIST_H */><>><>><>><>> |
352 | #endif /* _LINUX_SCATTERLIST_H */><>><>><>><>> |