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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 * esize; | |
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 * esize; | |
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 | BUG_ON(!nents); | |
565 | ||
566 | len = __kfifo_max_r(len, recsize); | |
567 | ||
568 | if (len + recsize > kfifo_unused(fifo)) | |
569 | return 0; | |
570 | ||
571 | return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize); | |
572 | } | |
573 | EXPORT_SYMBOL(__kfifo_dma_in_prepare_r); | |
574 | ||
575 | void __kfifo_dma_in_finish_r(struct __kfifo *fifo, | |
576 | unsigned int len, size_t recsize) | |
577 | { | |
578 | len = __kfifo_max_r(len, recsize); | |
579 | __kfifo_poke_n(fifo, len, recsize); | |
580 | fifo->in += len + recsize; | |
581 | } | |
582 | EXPORT_SYMBOL(__kfifo_dma_in_finish_r); | |
583 | ||
584 | unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo, | |
585 | struct scatterlist *sgl, int nents, unsigned int len, size_t recsize) | |
586 | { | |
587 | BUG_ON(!nents); | |
588 | ||
589 | len = __kfifo_max_r(len, recsize); | |
590 | ||
591 | if (len + recsize > fifo->in - fifo->out) | |
592 | return 0; | |
593 | ||
594 | return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize); | |
595 | } | |
596 | EXPORT_SYMBOL(__kfifo_dma_out_prepare_r); | |
597 | ||
598 | void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize) | |
599 | { | |
600 | unsigned int len; | |
601 | ||
602 | len = __kfifo_peek_n(fifo, recsize); | |
603 | fifo->out += len + recsize; | |
604 | } | |
605 | EXPORT_SYMBOL(__kfifo_dma_out_finish_r); |