Deleted Added
sdiff udiff text old ( 271127 ) new ( 273246 )
full compact
scatterlist.h (271127) scatterlist.h (273246)
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without

--- 17 unchanged lines hidden (view full) ---

26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#ifndef _LINUX_SCATTERLIST_H_
31#define _LINUX_SCATTERLIST_H_
32
33#include <linux/page.h>
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without

--- 17 unchanged lines hidden (view full) ---

26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#ifndef _LINUX_SCATTERLIST_H_
31#define _LINUX_SCATTERLIST_H_
32
33#include <linux/page.h>
34#include <linux/slab.h>
34
35
36/*
37 * SG table design.
38 *
39 * If flags bit 0 is set, then the sg field contains a pointer to the next sg
40 * table list. Otherwise the next entry is at sg + 1, can be determined using
41 * the sg_is_chain() function.
42 *
43 * If flags bit 1 is set, then this sg entry is the last element in a list,
44 * can be determined using the sg_is_last() function.
45 *
46 * See sg_next().
47 *
48 */
49
35struct scatterlist {
36 union {
37 struct page *page;
38 struct scatterlist *sg;
39 } sl_un;
40 dma_addr_t address;
41 unsigned long offset;
42 uint32_t length;
43 uint32_t flags;
44};
45
46struct sg_table {
47 struct scatterlist *sgl; /* the list */
48 unsigned int nents; /* number of mapped entries */
49 unsigned int orig_nents; /* original size of list */
50};
51
50struct scatterlist {
51 union {
52 struct page *page;
53 struct scatterlist *sg;
54 } sl_un;
55 dma_addr_t address;
56 unsigned long offset;
57 uint32_t length;
58 uint32_t flags;
59};
60
61struct sg_table {
62 struct scatterlist *sgl; /* the list */
63 unsigned int nents; /* number of mapped entries */
64 unsigned int orig_nents; /* original size of list */
65};
66
67/*
68 * Maximum number of entries that will be allocated in one piece, if
69 * a list larger than this is required then chaining will be utilized.
70 */
71#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist))
72
52#define sg_dma_address(sg) (sg)->address
53#define sg_dma_len(sg) (sg)->length
54#define sg_page(sg) (sg)->sl_un.page
55#define sg_scatternext(sg) (sg)->sl_un.sg
56
57#define SG_END 0x01
58#define SG_CHAIN 0x02
59

--- 34 unchanged lines hidden (view full) ---

94}
95
96static inline vm_paddr_t
97sg_phys(struct scatterlist *sg)
98{
99 return sg_page(sg)->phys_addr + sg->offset;
100}
101
73#define sg_dma_address(sg) (sg)->address
74#define sg_dma_len(sg) (sg)->length
75#define sg_page(sg) (sg)->sl_un.page
76#define sg_scatternext(sg) (sg)->sl_un.sg
77
78#define SG_END 0x01
79#define SG_CHAIN 0x02
80

--- 34 unchanged lines hidden (view full) ---

115}
116
117static inline vm_paddr_t
118sg_phys(struct scatterlist *sg)
119{
120 return sg_page(sg)->phys_addr + sg->offset;
121}
122
123/**
124 * sg_chain - Chain two sglists together
125 * @prv: First scatterlist
126 * @prv_nents: Number of entries in prv
127 * @sgl: Second scatterlist
128 *
129 * Description:
130 * Links @prv@ and @sgl@ together, to form a longer scatterlist.
131 *
132 **/
133static inline void
134sg_chain(struct scatterlist *prv, unsigned int prv_nents,
135 struct scatterlist *sgl)
136{
137/*
138 * offset and length are unused for chain entry. Clear them.
139 */
140 struct scatterlist *sg = &prv[prv_nents - 1];
141
142 sg->offset = 0;
143 sg->length = 0;
144
145 /*
146 * Indicate a link pointer, and set the link to the second list.
147 */
148 sg->flags = SG_CHAIN;
149 sg->sl_un.sg = sgl;
150}
151
152/**
153 * sg_mark_end - Mark the end of the scatterlist
154 * @sg: SG entryScatterlist
155 *
156 * Description:
157 * Marks the passed in sg entry as the termination point for the sg
158 * table. A call to sg_next() on this entry will return NULL.
159 *
160 **/
161static inline void sg_mark_end(struct scatterlist *sg)
162{
163 sg->flags = SG_END;
164}
165
166/**
167 * __sg_free_table - Free a previously mapped sg table
168 * @table: The sg table header to use
169 * @max_ents: The maximum number of entries per single scatterlist
170 *
171 * Description:
172 * Free an sg table previously allocated and setup with
173 * __sg_alloc_table(). The @max_ents value must be identical to
174 * that previously used with __sg_alloc_table().
175 *
176 **/
177static inline void
178__sg_free_table(struct sg_table *table, unsigned int max_ents)
179{
180 struct scatterlist *sgl, *next;
181
182 if (unlikely(!table->sgl))
183 return;
184
185 sgl = table->sgl;
186 while (table->orig_nents) {
187 unsigned int alloc_size = table->orig_nents;
188 unsigned int sg_size;
189
190 /*
191 * If we have more than max_ents segments left,
192 * then assign 'next' to the sg table after the current one.
193 * sg_size is then one less than alloc size, since the last
194 * element is the chain pointer.
195 */
196 if (alloc_size > max_ents) {
197 next = sgl[max_ents - 1].sl_un.sg;
198 alloc_size = max_ents;
199 sg_size = alloc_size - 1;
200 } else {
201 sg_size = alloc_size;
202 next = NULL;
203 }
204
205 table->orig_nents -= sg_size;
206 kfree(sgl);
207 sgl = next;
208 }
209
210 table->sgl = NULL;
211}
212
213/**
214 * sg_free_table - Free a previously allocated sg table
215 * @table: The mapped sg table header
216 *
217 **/
218static inline void
219sg_free_table(struct sg_table *table)
220{
221 __sg_free_table(table, SG_MAX_SINGLE_ALLOC);
222}
223
224/**
225 * __sg_alloc_table - Allocate and initialize an sg table with given allocator
226 * @table: The sg table header to use
227 * @nents: Number of entries in sg list
228 * @max_ents: The maximum number of entries the allocator returns per call
229 * @gfp_mask: GFP allocation mask
230 *
231 * Description:
232 * This function returns a @table @nents long. The allocator is
233 * defined to return scatterlist chunks of maximum size @max_ents.
234 * Thus if @nents is bigger than @max_ents, the scatterlists will be
235 * chained in units of @max_ents.
236 *
237 * Notes:
238 * If this function returns non-0 (eg failure), the caller must call
239 * __sg_free_table() to cleanup any leftover allocations.
240 *
241 **/
242static inline int
243__sg_alloc_table(struct sg_table *table, unsigned int nents,
244 unsigned int max_ents, gfp_t gfp_mask)
245{
246 struct scatterlist *sg, *prv;
247 unsigned int left;
248
249 memset(table, 0, sizeof(*table));
250
251 if (nents == 0)
252 return -EINVAL;
253 left = nents;
254 prv = NULL;
255 do {
256 unsigned int sg_size, alloc_size = left;
257
258 if (alloc_size > max_ents) {
259 alloc_size = max_ents;
260 sg_size = alloc_size - 1;
261 } else
262 sg_size = alloc_size;
263
264 left -= sg_size;
265
266 sg = kmalloc(alloc_size * sizeof(struct scatterlist), gfp_mask);
267 if (unlikely(!sg)) {
268 /*
269 * Adjust entry count to reflect that the last
270 * entry of the previous table won't be used for
271 * linkage. Without this, sg_kfree() may get
272 * confused.
273 */
274 if (prv)
275 table->nents = ++table->orig_nents;
276
277 return -ENOMEM;
278 }
279
280 sg_init_table(sg, alloc_size);
281 table->nents = table->orig_nents += sg_size;
282
283 /*
284 * If this is the first mapping, assign the sg table header.
285 * If this is not the first mapping, chain previous part.
286 */
287 if (prv)
288 sg_chain(prv, max_ents, sg);
289 else
290 table->sgl = sg;
291
292 /*
293 * If no more entries after this one, mark the end
294 */
295 if (!left)
296 sg_mark_end(&sg[sg_size - 1]);
297
298 prv = sg;
299 } while (left);
300
301 return 0;
302}
303
304/**
305 * sg_alloc_table - Allocate and initialize an sg table
306 * @table: The sg table header to use
307 * @nents: Number of entries in sg list
308 * @gfp_mask: GFP allocation mask
309 *
310 * Description:
311 * Allocate and initialize an sg table. If @nents@ is larger than
312 * SG_MAX_SINGLE_ALLOC a chained sg table will be setup.
313 *
314 **/
315
316static inline int
317sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
318{
319 int ret;
320
321 ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC,
322 gfp_mask);
323 if (unlikely(ret))
324 __sg_free_table(table, SG_MAX_SINGLE_ALLOC);
325
326 return ret;
327}
328
102#define for_each_sg(sglist, sg, sgmax, _itr) \
103 for (_itr = 0, sg = (sglist); _itr < (sgmax); _itr++, sg = sg_next(sg))
104
105#endif /* _LINUX_SCATTERLIST_H_ */
329#define for_each_sg(sglist, sg, sgmax, _itr) \
330 for (_itr = 0, sg = (sglist); _itr < (sgmax); _itr++, sg = sg_next(sg))
331
332#endif /* _LINUX_SCATTERLIST_H_ */