Root/
1 | /* |
2 | * A generic kernel FIFO implementation |
3 | * |
4 | * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net> |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify |
7 | * it under the terms of the GNU General Public License as published by |
8 | * the Free Software Foundation; either version 2 of the License, or |
9 | * (at your option) any later version. |
10 | * |
11 | * This program is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | * GNU General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU General Public License |
17 | * along with this program; if not, write to the Free Software |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
19 | * |
20 | */ |
21 | |
22 | #include <linux/kernel.h> |
23 | #include <linux/export.h> |
24 | #include <linux/slab.h> |
25 | #include <linux/err.h> |
26 | #include <linux/log2.h> |
27 | #include <linux/uaccess.h> |
28 | #include <linux/kfifo.h> |
29 | |
30 | /* |
31 | * internal helper to calculate the unused elements in a fifo |
32 | */ |
33 | static inline unsigned int kfifo_unused(struct __kfifo *fifo) |
34 | { |
35 | return (fifo->mask + 1) - (fifo->in - fifo->out); |
36 | } |
37 | |
38 | int __kfifo_alloc(struct __kfifo *fifo, unsigned int size, |
39 | size_t esize, gfp_t gfp_mask) |
40 | { |
41 | /* |
42 | * round down to the next power of 2, since our 'let the indices |
43 | * wrap' technique works only in this case. |
44 | */ |
45 | size = roundup_pow_of_two(size); |
46 | |
47 | fifo->in = 0; |
48 | fifo->out = 0; |
49 | fifo->esize = esize; |
50 | |
51 | if (size < 2) { |
52 | fifo->data = NULL; |
53 | fifo->mask = 0; |
54 | return -EINVAL; |
55 | } |
56 | |
57 | fifo->data = kmalloc(size * esize, gfp_mask); |
58 | |
59 | if (!fifo->data) { |
60 | fifo->mask = 0; |
61 | return -ENOMEM; |
62 | } |
63 | fifo->mask = size - 1; |
64 | |
65 | return 0; |
66 | } |
67 | EXPORT_SYMBOL(__kfifo_alloc); |
68 | |
69 | void __kfifo_free(struct __kfifo *fifo) |
70 | { |
71 | kfree(fifo->data); |
72 | fifo->in = 0; |
73 | fifo->out = 0; |
74 | fifo->esize = 0; |
75 | fifo->data = NULL; |
76 | fifo->mask = 0; |
77 | } |
78 | EXPORT_SYMBOL(__kfifo_free); |
79 | |
80 | int __kfifo_init(struct __kfifo *fifo, void *buffer, |
81 | unsigned int size, size_t esize) |
82 | { |
83 | size /= esize; |
84 | |
85 | size = roundup_pow_of_two(size); |
86 | |
87 | fifo->in = 0; |
88 | fifo->out = 0; |
89 | fifo->esize = esize; |
90 | fifo->data = buffer; |
91 | |
92 | if (size < 2) { |
93 | fifo->mask = 0; |
94 | return -EINVAL; |
95 | } |
96 | fifo->mask = size - 1; |
97 | |
98 | return 0; |
99 | } |
100 | EXPORT_SYMBOL(__kfifo_init); |
101 | |
102 | static void kfifo_copy_in(struct __kfifo *fifo, const void *src, |
103 | unsigned int len, unsigned int off) |
104 | { |
105 | unsigned int size = fifo->mask + 1; |
106 | unsigned int esize = fifo->esize; |
107 | unsigned int l; |
108 | |
109 | off &= fifo->mask; |
110 | if (esize != 1) { |
111 | off *= esize; |
112 | size *= esize; |
113 | len *= esize; |
114 | } |
115 | l = min(len, size - off); |
116 | |
117 | memcpy(fifo->data + off, src, l); |
118 | memcpy(fifo->data, src + l, len - l); |
119 | /* |
120 | * make sure that the data in the fifo is up to date before |
121 | * incrementing the fifo->in index counter |
122 | */ |
123 | smp_wmb(); |
124 | } |
125 | |
126 | unsigned int __kfifo_in(struct __kfifo *fifo, |
127 | const void *buf, unsigned int len) |
128 | { |
129 | unsigned int l; |
130 | |
131 | l = kfifo_unused(fifo); |
132 | if (len > l) |
133 | len = l; |
134 | |
135 | kfifo_copy_in(fifo, buf, len, fifo->in); |
136 | fifo->in += len; |
137 | return len; |
138 | } |
139 | EXPORT_SYMBOL(__kfifo_in); |
140 | |
141 | static void kfifo_copy_out(struct __kfifo *fifo, void *dst, |
142 | unsigned int len, unsigned int off) |
143 | { |
144 | unsigned int size = fifo->mask + 1; |
145 | unsigned int esize = fifo->esize; |
146 | unsigned int l; |
147 | |
148 | off &= fifo->mask; |
149 | if (esize != 1) { |
150 | off *= esize; |
151 | size *= esize; |
152 | len *= esize; |
153 | } |
154 | l = min(len, size - off); |
155 | |
156 | memcpy(dst, fifo->data + off, l); |
157 | memcpy(dst + l, fifo->data, len - l); |
158 | /* |
159 | * make sure that the data is copied before |
160 | * incrementing the fifo->out index counter |
161 | */ |
162 | smp_wmb(); |
163 | } |
164 | |
165 | unsigned int __kfifo_out_peek(struct __kfifo *fifo, |
166 | void *buf, unsigned int len) |
167 | { |
168 | unsigned int l; |
169 | |
170 | l = fifo->in - fifo->out; |
171 | if (len > l) |
172 | len = l; |
173 | |
174 | kfifo_copy_out(fifo, buf, len, fifo->out); |
175 | return len; |
176 | } |
177 | EXPORT_SYMBOL(__kfifo_out_peek); |
178 | |
179 | unsigned int __kfifo_out(struct __kfifo *fifo, |
180 | void *buf, unsigned int len) |
181 | { |
182 | len = __kfifo_out_peek(fifo, buf, len); |
183 | fifo->out += len; |
184 | return len; |
185 | } |
186 | EXPORT_SYMBOL(__kfifo_out); |
187 | |
188 | static unsigned long kfifo_copy_from_user(struct __kfifo *fifo, |
189 | const void __user *from, unsigned int len, unsigned int off, |
190 | unsigned int *copied) |
191 | { |
192 | unsigned int size = fifo->mask + 1; |
193 | unsigned int esize = fifo->esize; |
194 | unsigned int l; |
195 | unsigned long ret; |
196 | |
197 | off &= fifo->mask; |
198 | if (esize != 1) { |
199 | off *= esize; |
200 | size *= esize; |
201 | len *= esize; |
202 | } |
203 | l = min(len, size - off); |
204 | |
205 | ret = copy_from_user(fifo->data + off, from, l); |
206 | if (unlikely(ret)) |
207 | ret = DIV_ROUND_UP(ret + len - l, esize); |
208 | else { |
209 | ret = copy_from_user(fifo->data, from + l, len - l); |
210 | if (unlikely(ret)) |
211 | ret = DIV_ROUND_UP(ret, esize); |
212 | } |
213 | /* |
214 | * make sure that the data in the fifo is up to date before |
215 | * incrementing the fifo->in index counter |
216 | */ |
217 | smp_wmb(); |
218 | *copied = len - ret; |
219 | /* return the number of elements which are not copied */ |
220 | return ret; |
221 | } |
222 | |
223 | int __kfifo_from_user(struct __kfifo *fifo, const void __user *from, |
224 | unsigned long len, unsigned int *copied) |
225 | { |
226 | unsigned int l; |
227 | unsigned long ret; |
228 | unsigned int esize = fifo->esize; |
229 | int err; |
230 | |
231 | if (esize != 1) |
232 | len /= esize; |
233 | |
234 | l = kfifo_unused(fifo); |
235 | if (len > l) |
236 | len = l; |
237 | |
238 | ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied); |
239 | if (unlikely(ret)) { |
240 | len -= ret; |
241 | err = -EFAULT; |
242 | } else |
243 | err = 0; |
244 | fifo->in += len; |
245 | return err; |
246 | } |
247 | EXPORT_SYMBOL(__kfifo_from_user); |
248 | |
249 | static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to, |
250 | unsigned int len, unsigned int off, unsigned int *copied) |
251 | { |
252 | unsigned int l; |
253 | unsigned long ret; |
254 | unsigned int size = fifo->mask + 1; |
255 | unsigned int esize = fifo->esize; |
256 | |
257 | off &= fifo->mask; |
258 | if (esize != 1) { |
259 | off *= esize; |
260 | size *= esize; |
261 | len *= esize; |
262 | } |
263 | l = min(len, size - off); |
264 | |
265 | ret = copy_to_user(to, fifo->data + off, l); |
266 | if (unlikely(ret)) |
267 | ret = DIV_ROUND_UP(ret + len - l, esize); |
268 | else { |
269 | ret = copy_to_user(to + l, fifo->data, len - l); |
270 | if (unlikely(ret)) |
271 | ret = DIV_ROUND_UP(ret, esize); |
272 | } |
273 | /* |
274 | * make sure that the data is copied before |
275 | * incrementing the fifo->out index counter |
276 | */ |
277 | smp_wmb(); |
278 | *copied = len - ret; |
279 | /* return the number of elements which are not copied */ |
280 | return ret; |
281 | } |
282 | |
283 | int __kfifo_to_user(struct __kfifo *fifo, void __user *to, |
284 | unsigned long len, unsigned int *copied) |
285 | { |
286 | unsigned int l; |
287 | unsigned long ret; |
288 | unsigned int esize = fifo->esize; |
289 | int err; |
290 | |
291 | if (esize != 1) |
292 | len /= esize; |
293 | |
294 | l = fifo->in - fifo->out; |
295 | if (len > l) |
296 | len = l; |
297 | ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied); |
298 | if (unlikely(ret)) { |
299 | len -= ret; |
300 | err = -EFAULT; |
301 | } else |
302 | err = 0; |
303 | fifo->out += len; |
304 | return err; |
305 | } |
306 | EXPORT_SYMBOL(__kfifo_to_user); |
307 | |
308 | static int setup_sgl_buf(struct scatterlist *sgl, void *buf, |
309 | int nents, unsigned int len) |
310 | { |
311 | int n; |
312 | unsigned int l; |
313 | unsigned int off; |
314 | struct page *page; |
315 | |
316 | if (!nents) |
317 | return 0; |
318 | |
319 | if (!len) |
320 | return 0; |
321 | |
322 | n = 0; |
323 | page = virt_to_page(buf); |
324 | off = offset_in_page(buf); |
325 | l = 0; |
326 | |
327 | while (len >= l + PAGE_SIZE - off) { |
328 | struct page *npage; |
329 | |
330 | l += PAGE_SIZE; |
331 | buf += PAGE_SIZE; |
332 | npage = virt_to_page(buf); |
333 | if (page_to_phys(page) != page_to_phys(npage) - l) { |
334 | sg_set_page(sgl, page, l - off, off); |
335 | sgl = sg_next(sgl); |
336 | if (++n == nents || sgl == NULL) |
337 | return n; |
338 | page = npage; |
339 | len -= l - off; |
340 | l = off = 0; |
341 | } |
342 | } |
343 | sg_set_page(sgl, page, len, off); |
344 | return n + 1; |
345 | } |
346 | |
347 | static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl, |
348 | int nents, unsigned int len, unsigned int off) |
349 | { |
350 | unsigned int size = fifo->mask + 1; |
351 | unsigned int esize = fifo->esize; |
352 | unsigned int l; |
353 | unsigned int n; |
354 | |
355 | off &= fifo->mask; |
356 | if (esize != 1) { |
357 | off *= esize; |
358 | size *= esize; |
359 | len *= esize; |
360 | } |
361 | l = min(len, size - off); |
362 | |
363 | n = setup_sgl_buf(sgl, fifo->data + off, nents, l); |
364 | n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l); |
365 | |
366 | return n; |
367 | } |
368 | |
369 | unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo, |
370 | struct scatterlist *sgl, int nents, unsigned int len) |
371 | { |
372 | unsigned int l; |
373 | |
374 | l = kfifo_unused(fifo); |
375 | if (len > l) |
376 | len = l; |
377 | |
378 | return setup_sgl(fifo, sgl, nents, len, fifo->in); |
379 | } |
380 | EXPORT_SYMBOL(__kfifo_dma_in_prepare); |
381 | |
382 | unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo, |
383 | struct scatterlist *sgl, int nents, unsigned int len) |
384 | { |
385 | unsigned int l; |
386 | |
387 | l = fifo->in - fifo->out; |
388 | if (len > l) |
389 | len = l; |
390 | |
391 | return setup_sgl(fifo, sgl, nents, len, fifo->out); |
392 | } |
393 | EXPORT_SYMBOL(__kfifo_dma_out_prepare); |
394 | |
395 | unsigned int __kfifo_max_r(unsigned int len, size_t recsize) |
396 | { |
397 | unsigned int max = (1 << (recsize << 3)) - 1; |
398 | |
399 | if (len > max) |
400 | return max; |
401 | return len; |
402 | } |
403 | EXPORT_SYMBOL(__kfifo_max_r); |
404 | |
405 | #define __KFIFO_PEEK(data, out, mask) \ |
406 | ((data)[(out) & (mask)]) |
407 | /* |
408 | * __kfifo_peek_n internal helper function for determinate the length of |
409 | * the next record in the fifo |
410 | */ |
411 | static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize) |
412 | { |
413 | unsigned int l; |
414 | unsigned int mask = fifo->mask; |
415 | unsigned char *data = fifo->data; |
416 | |
417 | l = __KFIFO_PEEK(data, fifo->out, mask); |
418 | |
419 | if (--recsize) |
420 | l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8; |
421 | |
422 | return l; |
423 | } |
424 | |
425 | #define __KFIFO_POKE(data, in, mask, val) \ |
426 | ( \ |
427 | (data)[(in) & (mask)] = (unsigned char)(val) \ |
428 | ) |
429 | |
430 | /* |
431 | * __kfifo_poke_n internal helper function for storeing the length of |
432 | * the record into the fifo |
433 | */ |
434 | static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize) |
435 | { |
436 | unsigned int mask = fifo->mask; |
437 | unsigned char *data = fifo->data; |
438 | |
439 | __KFIFO_POKE(data, fifo->in, mask, n); |
440 | |
441 | if (recsize > 1) |
442 | __KFIFO_POKE(data, fifo->in + 1, mask, n >> 8); |
443 | } |
444 | |
445 | unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize) |
446 | { |
447 | return __kfifo_peek_n(fifo, recsize); |
448 | } |
449 | EXPORT_SYMBOL(__kfifo_len_r); |
450 | |
451 | unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf, |
452 | unsigned int len, size_t recsize) |
453 | { |
454 | if (len + recsize > kfifo_unused(fifo)) |
455 | return 0; |
456 | |
457 | __kfifo_poke_n(fifo, len, recsize); |
458 | |
459 | kfifo_copy_in(fifo, buf, len, fifo->in + recsize); |
460 | fifo->in += len + recsize; |
461 | return len; |
462 | } |
463 | EXPORT_SYMBOL(__kfifo_in_r); |
464 | |
465 | static unsigned int kfifo_out_copy_r(struct __kfifo *fifo, |
466 | void *buf, unsigned int len, size_t recsize, unsigned int *n) |
467 | { |
468 | *n = __kfifo_peek_n(fifo, recsize); |
469 | |
470 | if (len > *n) |
471 | len = *n; |
472 | |
473 | kfifo_copy_out(fifo, buf, len, fifo->out + recsize); |
474 | return len; |
475 | } |
476 | |
477 | unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf, |
478 | unsigned int len, size_t recsize) |
479 | { |
480 | unsigned int n; |
481 | |
482 | if (fifo->in == fifo->out) |
483 | return 0; |
484 | |
485 | return kfifo_out_copy_r(fifo, buf, len, recsize, &n); |
486 | } |
487 | EXPORT_SYMBOL(__kfifo_out_peek_r); |
488 | |
489 | unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf, |
490 | unsigned int len, size_t recsize) |
491 | { |
492 | unsigned int n; |
493 | |
494 | if (fifo->in == fifo->out) |
495 | return 0; |
496 | |
497 | len = kfifo_out_copy_r(fifo, buf, len, recsize, &n); |
498 | fifo->out += n + recsize; |
499 | return len; |
500 | } |
501 | EXPORT_SYMBOL(__kfifo_out_r); |
502 | |
503 | void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize) |
504 | { |
505 | unsigned int n; |
506 | |
507 | n = __kfifo_peek_n(fifo, recsize); |
508 | fifo->out += n + recsize; |
509 | } |
510 | EXPORT_SYMBOL(__kfifo_skip_r); |
511 | |
512 | int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from, |
513 | unsigned long len, unsigned int *copied, size_t recsize) |
514 | { |
515 | unsigned long ret; |
516 | |
517 | len = __kfifo_max_r(len, recsize); |
518 | |
519 | if (len + recsize > kfifo_unused(fifo)) { |
520 | *copied = 0; |
521 | return 0; |
522 | } |
523 | |
524 | __kfifo_poke_n(fifo, len, recsize); |
525 | |
526 | ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied); |
527 | if (unlikely(ret)) { |
528 | *copied = 0; |
529 | return -EFAULT; |
530 | } |
531 | fifo->in += len + recsize; |
532 | return 0; |
533 | } |
534 | EXPORT_SYMBOL(__kfifo_from_user_r); |
535 | |
536 | int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to, |
537 | unsigned long len, unsigned int *copied, size_t recsize) |
538 | { |
539 | unsigned long ret; |
540 | unsigned int n; |
541 | |
542 | if (fifo->in == fifo->out) { |
543 | *copied = 0; |
544 | return 0; |
545 | } |
546 | |
547 | n = __kfifo_peek_n(fifo, recsize); |
548 | if (len > n) |
549 | len = n; |
550 | |
551 | ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied); |
552 | if (unlikely(ret)) { |
553 | *copied = 0; |
554 | return -EFAULT; |
555 | } |
556 | fifo->out += n + recsize; |
557 | return 0; |
558 | } |
559 | EXPORT_SYMBOL(__kfifo_to_user_r); |
560 | |
561 | unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo, |
562 | struct scatterlist *sgl, int nents, unsigned int len, size_t recsize) |
563 | { |
564 | if (!nents) |
565 | BUG(); |
566 | |
567 | len = __kfifo_max_r(len, recsize); |
568 | |
569 | if (len + recsize > kfifo_unused(fifo)) |
570 | return 0; |
571 | |
572 | return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize); |
573 | } |
574 | EXPORT_SYMBOL(__kfifo_dma_in_prepare_r); |
575 | |
576 | void __kfifo_dma_in_finish_r(struct __kfifo *fifo, |
577 | unsigned int len, size_t recsize) |
578 | { |
579 | len = __kfifo_max_r(len, recsize); |
580 | __kfifo_poke_n(fifo, len, recsize); |
581 | fifo->in += len + recsize; |
582 | } |
583 | EXPORT_SYMBOL(__kfifo_dma_in_finish_r); |
584 | |
585 | unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo, |
586 | struct scatterlist *sgl, int nents, unsigned int len, size_t recsize) |
587 | { |
588 | if (!nents) |
589 | BUG(); |
590 | |
591 | len = __kfifo_max_r(len, recsize); |
592 | |
593 | if (len + recsize > fifo->in - fifo->out) |
594 | return 0; |
595 | |
596 | return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize); |
597 | } |
598 | EXPORT_SYMBOL(__kfifo_dma_out_prepare_r); |
599 | |
600 | void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize) |
601 | { |
602 | unsigned int len; |
603 | |
604 | len = __kfifo_peek_n(fifo, recsize); |
605 | fifo->out += len + recsize; |
606 | } |
607 | EXPORT_SYMBOL(__kfifo_dma_out_finish_r); |
608 |
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