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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Stefani Seibold2e956fb2010-08-10 18:03:38 -07002 * A generic kernel FIFO implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
Stefani Seibold2e956fb2010-08-10 18:03:38 -07004 * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
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
Stefani Seiboldd78a3ed2010-08-11 14:17:27 -070013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 * 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/module.h>
24#include <linux/slab.h>
25#include <linux/err.h>
vignesh babuf84d5a72007-07-15 23:41:34 -070026#include <linux/log2.h>
Stefani Seibolda121f242009-12-21 14:37:31 -080027#include <linux/uaccess.h>
Stefani Seibold2e956fb2010-08-10 18:03:38 -070028#include <linux/kfifo.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Stefani Seibold2e956fb2010-08-10 18:03:38 -070030/*
31 * internal helper to calculate the unused elements in a fifo
32 */
33static inline unsigned int kfifo_unused(struct __kfifo *fifo)
Stefani Seibold45465482009-12-21 14:37:26 -080034{
Stefani Seibold2e956fb2010-08-10 18:03:38 -070035 return (fifo->mask + 1) - (fifo->in - fifo->out);
Stefani Seibold45465482009-12-21 14:37:26 -080036}
37
Stefani Seibold2e956fb2010-08-10 18:03:38 -070038int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
39 size_t esize, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -070040{
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 /*
Stefani Seibold2e956fb2010-08-10 18:03:38 -070042 * round down to the next power of 2, since our 'let the indices
Robert P. J. Dayb33112d2009-06-16 15:33:34 -070043 * wrap' technique works only in this case.
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 */
Stefani Seibold2e956fb2010-08-10 18:03:38 -070045 if (!is_power_of_2(size))
46 size = rounddown_pow_of_two(size);
47
48 fifo->in = 0;
49 fifo->out = 0;
50 fifo->esize = esize;
51
52 if (size < 2) {
53 fifo->data = NULL;
54 fifo->mask = 0;
55 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 }
57
Stefani Seibold2e956fb2010-08-10 18:03:38 -070058 fifo->data = kmalloc(size * esize, gfp_mask);
59
60 if (!fifo->data) {
61 fifo->mask = 0;
Stefani Seibold45465482009-12-21 14:37:26 -080062 return -ENOMEM;
63 }
Stefani Seibold2e956fb2010-08-10 18:03:38 -070064 fifo->mask = size - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Stefani Seibold45465482009-12-21 14:37:26 -080066 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067}
Stefani Seibold2e956fb2010-08-10 18:03:38 -070068EXPORT_SYMBOL(__kfifo_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
Stefani Seibold2e956fb2010-08-10 18:03:38 -070070void __kfifo_free(struct __kfifo *fifo)
Linus Torvalds1da177e2005-04-16 15:20:36 -070071{
Stefani Seibold2e956fb2010-08-10 18:03:38 -070072 kfree(fifo->data);
73 fifo->in = 0;
74 fifo->out = 0;
75 fifo->esize = 0;
76 fifo->data = NULL;
77 fifo->mask = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078}
Stefani Seibold2e956fb2010-08-10 18:03:38 -070079EXPORT_SYMBOL(__kfifo_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
Stefani Seibold2e956fb2010-08-10 18:03:38 -070081int __kfifo_init(struct __kfifo *fifo, void *buffer,
82 unsigned int size, size_t esize)
Stefani Seibolda121f242009-12-21 14:37:31 -080083{
Stefani Seibold2e956fb2010-08-10 18:03:38 -070084 size /= esize;
85
86 if (!is_power_of_2(size))
87 size = rounddown_pow_of_two(size);
88
89 fifo->in = 0;
90 fifo->out = 0;
91 fifo->esize = esize;
92 fifo->data = buffer;
93
94 if (size < 2) {
95 fifo->mask = 0;
96 return -EINVAL;
Stefani Seibolda121f242009-12-21 14:37:31 -080097 }
Stefani Seibold2e956fb2010-08-10 18:03:38 -070098 fifo->mask = size - 1;
Stefani Seibolda121f242009-12-21 14:37:31 -080099
Andi Kleen64ce1032010-01-15 17:01:15 -0800100 return 0;
Stefani Seibold86d48802009-12-21 14:37:32 -0800101}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700102EXPORT_SYMBOL(__kfifo_init);
Stefani Seibold86d48802009-12-21 14:37:32 -0800103
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700104static void kfifo_copy_in(struct __kfifo *fifo, const void *src,
105 unsigned int len, unsigned int off)
Stefani Seibold86d48802009-12-21 14:37:32 -0800106{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700107 unsigned int size = fifo->mask + 1;
108 unsigned int esize = fifo->esize;
109 unsigned int l;
Stefani Seibold86d48802009-12-21 14:37:32 -0800110
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700111 off &= fifo->mask;
112 if (esize != 1) {
113 off *= esize;
114 size *= esize;
115 len *= esize;
116 }
117 l = min(len, size - off);
118
119 memcpy(fifo->data + off, src, l);
120 memcpy(fifo->data, src + l, len - l);
121 /*
122 * make sure that the data in the fifo is up to date before
123 * incrementing the fifo->in index counter
124 */
125 smp_wmb();
Stefani Seibold86d48802009-12-21 14:37:32 -0800126}
Stefani Seibold86d48802009-12-21 14:37:32 -0800127
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700128unsigned int __kfifo_in(struct __kfifo *fifo,
129 const void *buf, unsigned int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700131 unsigned int l;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700133 l = kfifo_unused(fifo);
134 if (len > l)
135 len = l;
136
137 kfifo_copy_in(fifo, buf, len, fifo->in);
138 fifo->in += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 return len;
140}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700141EXPORT_SYMBOL(__kfifo_in);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700143static void kfifo_copy_out(struct __kfifo *fifo, void *dst,
144 unsigned int len, unsigned int off)
Stefani Seibold86d48802009-12-21 14:37:32 -0800145{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700146 unsigned int size = fifo->mask + 1;
147 unsigned int esize = fifo->esize;
148 unsigned int l;
149
150 off &= fifo->mask;
151 if (esize != 1) {
152 off *= esize;
153 size *= esize;
154 len *= esize;
155 }
156 l = min(len, size - off);
157
158 memcpy(dst, fifo->data + off, l);
159 memcpy(dst + l, fifo->data, len - l);
160 /*
161 * make sure that the data is copied before
162 * incrementing the fifo->out index counter
163 */
164 smp_wmb();
Stefani Seibold86d48802009-12-21 14:37:32 -0800165}
Stefani Seibold86d48802009-12-21 14:37:32 -0800166
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700167unsigned int __kfifo_out_peek(struct __kfifo *fifo,
168 void *buf, unsigned int len)
Stefani Seibold86d48802009-12-21 14:37:32 -0800169{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700170 unsigned int l;
Stefani Seibold86d48802009-12-21 14:37:32 -0800171
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700172 l = fifo->in - fifo->out;
173 if (len > l)
174 len = l;
Stefani Seibold86d48802009-12-21 14:37:32 -0800175
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700176 kfifo_copy_out(fifo, buf, len, fifo->out);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 return len;
178}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700179EXPORT_SYMBOL(__kfifo_out_peek);
Stefani Seibolda121f242009-12-21 14:37:31 -0800180
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700181unsigned int __kfifo_out(struct __kfifo *fifo,
182 void *buf, unsigned int len)
Andi Kleena5b9e2c2010-01-15 17:01:16 -0800183{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700184 len = __kfifo_out_peek(fifo, buf, len);
185 fifo->out += len;
Andi Kleena5b9e2c2010-01-15 17:01:16 -0800186 return len;
187}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700188EXPORT_SYMBOL(__kfifo_out);
Andi Kleena5b9e2c2010-01-15 17:01:16 -0800189
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700190static unsigned long kfifo_copy_from_user(struct __kfifo *fifo,
191 const void __user *from, unsigned int len, unsigned int off,
192 unsigned int *copied)
Stefani Seibold86d48802009-12-21 14:37:32 -0800193{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700194 unsigned int size = fifo->mask + 1;
195 unsigned int esize = fifo->esize;
196 unsigned int l;
197 unsigned long ret;
Stefani Seibold86d48802009-12-21 14:37:32 -0800198
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700199 off &= fifo->mask;
200 if (esize != 1) {
201 off *= esize;
202 size *= esize;
203 len *= esize;
204 }
205 l = min(len, size - off);
Andi Kleen64ce1032010-01-15 17:01:15 -0800206
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700207 ret = copy_from_user(fifo->data + off, from, l);
208 if (unlikely(ret))
209 ret = DIV_ROUND_UP(ret + len - l, esize);
210 else {
211 ret = copy_from_user(fifo->data, from + l, len - l);
212 if (unlikely(ret))
213 ret = DIV_ROUND_UP(ret, esize);
214 }
215 /*
216 * make sure that the data in the fifo is up to date before
217 * incrementing the fifo->in index counter
218 */
219 smp_wmb();
220 *copied = len - ret;
221 /* return the number of elements which are not copied */
Andi Kleen64ce1032010-01-15 17:01:15 -0800222 return ret;
Stefani Seibolda121f242009-12-21 14:37:31 -0800223}
Stefani Seibolda121f242009-12-21 14:37:31 -0800224
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700225int __kfifo_from_user(struct __kfifo *fifo, const void __user *from,
226 unsigned long len, unsigned int *copied)
Stefani Seibold86d48802009-12-21 14:37:32 -0800227{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700228 unsigned int l;
229 unsigned long ret;
230 unsigned int esize = fifo->esize;
231 int err;
232
233 if (esize != 1)
234 len /= esize;
235
236 l = kfifo_unused(fifo);
237 if (len > l)
238 len = l;
239
240 ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied);
241 if (unlikely(ret)) {
242 len -= ret;
243 err = -EFAULT;
244 } else
245 err = 0;
246 fifo->in += len;
247 return err;
Stefani Seibold86d48802009-12-21 14:37:32 -0800248}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700249EXPORT_SYMBOL(__kfifo_from_user);
Stefani Seibold86d48802009-12-21 14:37:32 -0800250
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700251static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to,
252 unsigned int len, unsigned int off, unsigned int *copied)
Stefani Seibold86d48802009-12-21 14:37:32 -0800253{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700254 unsigned int l;
255 unsigned long ret;
256 unsigned int size = fifo->mask + 1;
257 unsigned int esize = fifo->esize;
Stefani Seibold86d48802009-12-21 14:37:32 -0800258
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700259 off &= fifo->mask;
260 if (esize != 1) {
261 off *= esize;
262 size *= esize;
263 len *= esize;
264 }
265 l = min(len, size - off);
266
267 ret = copy_to_user(to, fifo->data + off, l);
268 if (unlikely(ret))
269 ret = DIV_ROUND_UP(ret + len - l, esize);
270 else {
271 ret = copy_to_user(to + l, fifo->data, len - l);
272 if (unlikely(ret))
273 ret = DIV_ROUND_UP(ret, esize);
274 }
275 /*
276 * make sure that the data is copied before
277 * incrementing the fifo->out index counter
278 */
279 smp_wmb();
280 *copied = len - ret;
281 /* return the number of elements which are not copied */
282 return ret;
283}
284
285int __kfifo_to_user(struct __kfifo *fifo, void __user *to,
286 unsigned long len, unsigned int *copied)
287{
288 unsigned int l;
289 unsigned long ret;
290 unsigned int esize = fifo->esize;
291 int err;
292
293 if (esize != 1)
294 len /= esize;
295
296 l = fifo->in - fifo->out;
297 if (len > l)
298 len = l;
299 ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied);
300 if (unlikely(ret)) {
301 len -= ret;
302 err = -EFAULT;
303 } else
304 err = 0;
305 fifo->out += len;
306 return err;
307}
308EXPORT_SYMBOL(__kfifo_to_user);
309
310static int setup_sgl_buf(struct scatterlist *sgl, void *buf,
311 int nents, unsigned int len)
312{
313 int n;
314 unsigned int l;
315 unsigned int off;
316 struct page *page;
317
318 if (!nents)
319 return 0;
320
321 if (!len)
322 return 0;
323
324 n = 0;
325 page = virt_to_page(buf);
326 off = offset_in_page(buf);
327 l = 0;
328
329 while (len >= l + PAGE_SIZE - off) {
330 struct page *npage;
331
332 l += PAGE_SIZE;
333 buf += PAGE_SIZE;
334 npage = virt_to_page(buf);
335 if (page_to_phys(page) != page_to_phys(npage) - l) {
Stefani Seiboldd78a3ed2010-08-11 14:17:27 -0700336 sg_set_page(sgl, page, l - off, off);
337 sgl = sg_next(sgl);
338 if (++n == nents || sgl == NULL)
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700339 return n;
340 page = npage;
341 len -= l - off;
342 l = off = 0;
343 }
344 }
Stefani Seiboldd78a3ed2010-08-11 14:17:27 -0700345 sg_set_page(sgl, page, len, off);
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700346 return n + 1;
347}
348
349static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
350 int nents, unsigned int len, unsigned int off)
351{
352 unsigned int size = fifo->mask + 1;
353 unsigned int esize = fifo->esize;
354 unsigned int l;
355 unsigned int n;
356
357 off &= fifo->mask;
358 if (esize != 1) {
359 off *= esize;
360 size *= esize;
361 len *= esize;
362 }
363 l = min(len, size - off);
364
Stefani Seiboldd78a3ed2010-08-11 14:17:27 -0700365 n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700366 n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);
367
368 if (n)
369 sg_mark_end(sgl + n - 1);
370 return n;
371}
372
373unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
374 struct scatterlist *sgl, int nents, unsigned int len)
375{
376 unsigned int l;
377
378 l = kfifo_unused(fifo);
379 if (len > l)
380 len = l;
381
382 return setup_sgl(fifo, sgl, nents, len, fifo->in);
383}
384EXPORT_SYMBOL(__kfifo_dma_in_prepare);
385
386unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
387 struct scatterlist *sgl, int nents, unsigned int len)
388{
389 unsigned int l;
390
391 l = fifo->in - fifo->out;
392 if (len > l)
393 len = l;
394
395 return setup_sgl(fifo, sgl, nents, len, fifo->out);
396}
397EXPORT_SYMBOL(__kfifo_dma_out_prepare);
398
399unsigned int __kfifo_max_r(unsigned int len, size_t recsize)
400{
401 unsigned int max = (1 << (recsize << 3)) - 1;
402
403 if (len > max)
404 return max;
405 return len;
406}
407
408#define __KFIFO_PEEK(data, out, mask) \
409 ((data)[(out) & (mask)])
410/*
411 * __kfifo_peek_n internal helper function for determinate the length of
412 * the next record in the fifo
413 */
414static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize)
415{
416 unsigned int l;
417 unsigned int mask = fifo->mask;
418 unsigned char *data = fifo->data;
419
420 l = __KFIFO_PEEK(data, fifo->out, mask);
421
422 if (--recsize)
423 l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8;
424
425 return l;
426}
427
428#define __KFIFO_POKE(data, in, mask, val) \
429 ( \
430 (data)[(in) & (mask)] = (unsigned char)(val) \
431 )
432
433/*
434 * __kfifo_poke_n internal helper function for storeing the length of
435 * the record into the fifo
436 */
437static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize)
438{
439 unsigned int mask = fifo->mask;
440 unsigned char *data = fifo->data;
441
442 __KFIFO_POKE(data, fifo->in, mask, n);
443
444 if (recsize > 1)
445 __KFIFO_POKE(data, fifo->in + 1, mask, n >> 8);
446}
447
448unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize)
449{
Stefani Seibold86d48802009-12-21 14:37:32 -0800450 return __kfifo_peek_n(fifo, recsize);
451}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700452EXPORT_SYMBOL(__kfifo_len_r);
Stefani Seibold86d48802009-12-21 14:37:32 -0800453
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700454unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf,
455 unsigned int len, size_t recsize)
Stefani Seibold86d48802009-12-21 14:37:32 -0800456{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700457 if (len + recsize > kfifo_unused(fifo))
458 return 0;
Stefani Seibold86d48802009-12-21 14:37:32 -0800459
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700460 __kfifo_poke_n(fifo, len, recsize);
461
462 kfifo_copy_in(fifo, buf, len, fifo->in + recsize);
463 fifo->in += len + recsize;
464 return len;
465}
466EXPORT_SYMBOL(__kfifo_in_r);
467
468static unsigned int kfifo_out_copy_r(struct __kfifo *fifo,
469 void *buf, unsigned int len, size_t recsize, unsigned int *n)
470{
471 *n = __kfifo_peek_n(fifo, recsize);
472
473 if (len > *n)
474 len = *n;
475
476 kfifo_copy_out(fifo, buf, len, fifo->out + recsize);
477 return len;
478}
479
480unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf,
481 unsigned int len, size_t recsize)
482{
483 unsigned int n;
484
485 if (fifo->in == fifo->out)
486 return 0;
487
488 return kfifo_out_copy_r(fifo, buf, len, recsize, &n);
489}
490EXPORT_SYMBOL(__kfifo_out_peek_r);
491
492unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,
493 unsigned int len, size_t recsize)
494{
495 unsigned int n;
496
497 if (fifo->in == fifo->out)
498 return 0;
499
500 len = kfifo_out_copy_r(fifo, buf, len, recsize, &n);
501 fifo->out += n + recsize;
502 return len;
503}
504EXPORT_SYMBOL(__kfifo_out_r);
505
Andrea Righib35de432010-08-19 14:13:27 -0700506void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize)
507{
508 unsigned int n;
509
510 n = __kfifo_peek_n(fifo, recsize);
511 fifo->out += n + recsize;
512}
513EXPORT_SYMBOL(__kfifo_skip_r);
514
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700515int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from,
516 unsigned long len, unsigned int *copied, size_t recsize)
517{
518 unsigned long ret;
519
520 len = __kfifo_max_r(len, recsize);
521
522 if (len + recsize > kfifo_unused(fifo)) {
523 *copied = 0;
524 return 0;
525 }
526
527 __kfifo_poke_n(fifo, len, recsize);
528
529 ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied);
530 if (unlikely(ret)) {
531 *copied = 0;
532 return -EFAULT;
533 }
534 fifo->in += len + recsize;
535 return 0;
536}
537EXPORT_SYMBOL(__kfifo_from_user_r);
538
539int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
540 unsigned long len, unsigned int *copied, size_t recsize)
541{
542 unsigned long ret;
543 unsigned int n;
544
545 if (fifo->in == fifo->out) {
546 *copied = 0;
547 return 0;
548 }
549
550 n = __kfifo_peek_n(fifo, recsize);
551 if (len > n)
552 len = n;
553
554 ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied);
555 if (unlikely(ret)) {
556 *copied = 0;
557 return -EFAULT;
558 }
559 fifo->out += n + recsize;
560 return 0;
561}
562EXPORT_SYMBOL(__kfifo_to_user_r);
563
564unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
565 struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
566{
567 if (!nents)
568 BUG();
569
570 len = __kfifo_max_r(len, recsize);
571
572 if (len + recsize > kfifo_unused(fifo))
573 return 0;
574
575 return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);
576}
577EXPORT_SYMBOL(__kfifo_dma_in_prepare_r);
578
579void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
580 unsigned int len, size_t recsize)
581{
582 len = __kfifo_max_r(len, recsize);
583 __kfifo_poke_n(fifo, len, recsize);
584 fifo->in += len + recsize;
585}
586EXPORT_SYMBOL(__kfifo_dma_in_finish_r);
587
588unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
589 struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
590{
591 if (!nents)
592 BUG();
593
594 len = __kfifo_max_r(len, recsize);
595
596 if (len + recsize > fifo->in - fifo->out)
597 return 0;
598
599 return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);
600}
601EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);
602
603void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize)
604{
605 unsigned int len;
606
607 len = __kfifo_peek_n(fifo, recsize);
608 fifo->out += len + recsize;
609}
610EXPORT_SYMBOL(__kfifo_dma_out_finish_r);