blob: 12f5a347aa137088a5364c3dcb0919a316fd7e88 [file] [log] [blame]
Thomas Gleixner74ba9202019-05-20 09:19:02 +02001// SPDX-License-Identifier: GPL-2.0-or-later
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
Stefani Seibold2e956fb2010-08-10 18:03:38 -07003 * A generic kernel FIFO implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
Stefani Seibold2e956fb2010-08-10 18:03:38 -07005 * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 */
7
8#include <linux/kernel.h>
Paul Gortmaker9984de12011-05-23 14:51:41 -04009#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/slab.h>
11#include <linux/err.h>
vignesh babuf84d5a72007-07-15 23:41:34 -070012#include <linux/log2.h>
Stefani Seibolda121f242009-12-21 14:37:31 -080013#include <linux/uaccess.h>
Stefani Seibold2e956fb2010-08-10 18:03:38 -070014#include <linux/kfifo.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
Stefani Seibold2e956fb2010-08-10 18:03:38 -070016/*
17 * internal helper to calculate the unused elements in a fifo
18 */
19static inline unsigned int kfifo_unused(struct __kfifo *fifo)
Stefani Seibold45465482009-12-21 14:37:26 -080020{
Stefani Seibold2e956fb2010-08-10 18:03:38 -070021 return (fifo->mask + 1) - (fifo->in - fifo->out);
Stefani Seibold45465482009-12-21 14:37:26 -080022}
23
Stefani Seibold2e956fb2010-08-10 18:03:38 -070024int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
25 size_t esize, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -070026{
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 /*
Martin Kelly75a24b82018-03-26 11:18:23 -070028 * round up to the next power of 2, since our 'let the indices
Robert P. J. Dayb33112d2009-06-16 15:33:34 -070029 * wrap' technique works only in this case.
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 */
Stefani Seibolddfe2a772013-02-27 17:05:51 -080031 size = roundup_pow_of_two(size);
Stefani Seibold2e956fb2010-08-10 18:03:38 -070032
33 fifo->in = 0;
34 fifo->out = 0;
35 fifo->esize = esize;
36
37 if (size < 2) {
38 fifo->data = NULL;
39 fifo->mask = 0;
40 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 }
42
Kees Cook6da2ec52018-06-12 13:55:00 -070043 fifo->data = kmalloc_array(esize, size, gfp_mask);
Stefani Seibold2e956fb2010-08-10 18:03:38 -070044
45 if (!fifo->data) {
46 fifo->mask = 0;
Stefani Seibold45465482009-12-21 14:37:26 -080047 return -ENOMEM;
48 }
Stefani Seibold2e956fb2010-08-10 18:03:38 -070049 fifo->mask = size - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Stefani Seibold45465482009-12-21 14:37:26 -080051 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052}
Stefani Seibold2e956fb2010-08-10 18:03:38 -070053EXPORT_SYMBOL(__kfifo_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
Stefani Seibold2e956fb2010-08-10 18:03:38 -070055void __kfifo_free(struct __kfifo *fifo)
Linus Torvalds1da177e2005-04-16 15:20:36 -070056{
Stefani Seibold2e956fb2010-08-10 18:03:38 -070057 kfree(fifo->data);
58 fifo->in = 0;
59 fifo->out = 0;
60 fifo->esize = 0;
61 fifo->data = NULL;
62 fifo->mask = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063}
Stefani Seibold2e956fb2010-08-10 18:03:38 -070064EXPORT_SYMBOL(__kfifo_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Stefani Seibold2e956fb2010-08-10 18:03:38 -070066int __kfifo_init(struct __kfifo *fifo, void *buffer,
67 unsigned int size, size_t esize)
Stefani Seibolda121f242009-12-21 14:37:31 -080068{
Stefani Seibold2e956fb2010-08-10 18:03:38 -070069 size /= esize;
70
Linus Torvaldsab9bb632019-08-30 18:47:15 -070071 if (!is_power_of_2(size))
72 size = rounddown_pow_of_two(size);
Stefani Seibold2e956fb2010-08-10 18:03:38 -070073
74 fifo->in = 0;
75 fifo->out = 0;
76 fifo->esize = esize;
77 fifo->data = buffer;
78
79 if (size < 2) {
80 fifo->mask = 0;
81 return -EINVAL;
Stefani Seibolda121f242009-12-21 14:37:31 -080082 }
Stefani Seibold2e956fb2010-08-10 18:03:38 -070083 fifo->mask = size - 1;
Stefani Seibolda121f242009-12-21 14:37:31 -080084
Andi Kleen64ce1032010-01-15 17:01:15 -080085 return 0;
Stefani Seibold86d48802009-12-21 14:37:32 -080086}
Stefani Seibold2e956fb2010-08-10 18:03:38 -070087EXPORT_SYMBOL(__kfifo_init);
Stefani Seibold86d48802009-12-21 14:37:32 -080088
Stefani Seibold2e956fb2010-08-10 18:03:38 -070089static void kfifo_copy_in(struct __kfifo *fifo, const void *src,
90 unsigned int len, unsigned int off)
Stefani Seibold86d48802009-12-21 14:37:32 -080091{
Stefani Seibold2e956fb2010-08-10 18:03:38 -070092 unsigned int size = fifo->mask + 1;
93 unsigned int esize = fifo->esize;
94 unsigned int l;
Stefani Seibold86d48802009-12-21 14:37:32 -080095
Stefani Seibold2e956fb2010-08-10 18:03:38 -070096 off &= fifo->mask;
97 if (esize != 1) {
98 off *= esize;
99 size *= esize;
100 len *= esize;
101 }
102 l = min(len, size - off);
103
104 memcpy(fifo->data + off, src, l);
105 memcpy(fifo->data, src + l, len - l);
106 /*
107 * make sure that the data in the fifo is up to date before
108 * incrementing the fifo->in index counter
109 */
110 smp_wmb();
Stefani Seibold86d48802009-12-21 14:37:32 -0800111}
Stefani Seibold86d48802009-12-21 14:37:32 -0800112
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700113unsigned int __kfifo_in(struct __kfifo *fifo,
114 const void *buf, unsigned int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700116 unsigned int l;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700118 l = kfifo_unused(fifo);
119 if (len > l)
120 len = l;
121
122 kfifo_copy_in(fifo, buf, len, fifo->in);
123 fifo->in += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 return len;
125}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700126EXPORT_SYMBOL(__kfifo_in);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700128static void kfifo_copy_out(struct __kfifo *fifo, void *dst,
129 unsigned int len, unsigned int off)
Stefani Seibold86d48802009-12-21 14:37:32 -0800130{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700131 unsigned int size = fifo->mask + 1;
132 unsigned int esize = fifo->esize;
133 unsigned int l;
134
135 off &= fifo->mask;
136 if (esize != 1) {
137 off *= esize;
138 size *= esize;
139 len *= esize;
140 }
141 l = min(len, size - off);
142
143 memcpy(dst, fifo->data + off, l);
144 memcpy(dst + l, fifo->data, len - l);
145 /*
146 * make sure that the data is copied before
147 * incrementing the fifo->out index counter
148 */
149 smp_wmb();
Stefani Seibold86d48802009-12-21 14:37:32 -0800150}
Stefani Seibold86d48802009-12-21 14:37:32 -0800151
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700152unsigned int __kfifo_out_peek(struct __kfifo *fifo,
153 void *buf, unsigned int len)
Stefani Seibold86d48802009-12-21 14:37:32 -0800154{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700155 unsigned int l;
Stefani Seibold86d48802009-12-21 14:37:32 -0800156
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700157 l = fifo->in - fifo->out;
158 if (len > l)
159 len = l;
Stefani Seibold86d48802009-12-21 14:37:32 -0800160
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700161 kfifo_copy_out(fifo, buf, len, fifo->out);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 return len;
163}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700164EXPORT_SYMBOL(__kfifo_out_peek);
Stefani Seibolda121f242009-12-21 14:37:31 -0800165
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700166unsigned int __kfifo_out(struct __kfifo *fifo,
167 void *buf, unsigned int len)
Andi Kleena5b9e2c2010-01-15 17:01:16 -0800168{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700169 len = __kfifo_out_peek(fifo, buf, len);
170 fifo->out += len;
Andi Kleena5b9e2c2010-01-15 17:01:16 -0800171 return len;
172}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700173EXPORT_SYMBOL(__kfifo_out);
Andi Kleena5b9e2c2010-01-15 17:01:16 -0800174
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700175static unsigned long kfifo_copy_from_user(struct __kfifo *fifo,
176 const void __user *from, unsigned int len, unsigned int off,
177 unsigned int *copied)
Stefani Seibold86d48802009-12-21 14:37:32 -0800178{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700179 unsigned int size = fifo->mask + 1;
180 unsigned int esize = fifo->esize;
181 unsigned int l;
182 unsigned long ret;
Stefani Seibold86d48802009-12-21 14:37:32 -0800183
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700184 off &= fifo->mask;
185 if (esize != 1) {
186 off *= esize;
187 size *= esize;
188 len *= esize;
189 }
190 l = min(len, size - off);
Andi Kleen64ce1032010-01-15 17:01:15 -0800191
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700192 ret = copy_from_user(fifo->data + off, from, l);
193 if (unlikely(ret))
194 ret = DIV_ROUND_UP(ret + len - l, esize);
195 else {
196 ret = copy_from_user(fifo->data, from + l, len - l);
197 if (unlikely(ret))
198 ret = DIV_ROUND_UP(ret, esize);
199 }
200 /*
201 * make sure that the data in the fifo is up to date before
202 * incrementing the fifo->in index counter
203 */
204 smp_wmb();
Lars-Peter Clausena019e482013-11-14 14:32:16 -0800205 *copied = len - ret * esize;
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700206 /* return the number of elements which are not copied */
Andi Kleen64ce1032010-01-15 17:01:15 -0800207 return ret;
Stefani Seibolda121f242009-12-21 14:37:31 -0800208}
Stefani Seibolda121f242009-12-21 14:37:31 -0800209
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700210int __kfifo_from_user(struct __kfifo *fifo, const void __user *from,
211 unsigned long len, unsigned int *copied)
Stefani Seibold86d48802009-12-21 14:37:32 -0800212{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700213 unsigned int l;
214 unsigned long ret;
215 unsigned int esize = fifo->esize;
216 int err;
217
218 if (esize != 1)
219 len /= esize;
220
221 l = kfifo_unused(fifo);
222 if (len > l)
223 len = l;
224
225 ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied);
226 if (unlikely(ret)) {
227 len -= ret;
228 err = -EFAULT;
229 } else
230 err = 0;
231 fifo->in += len;
232 return err;
Stefani Seibold86d48802009-12-21 14:37:32 -0800233}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700234EXPORT_SYMBOL(__kfifo_from_user);
Stefani Seibold86d48802009-12-21 14:37:32 -0800235
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700236static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to,
237 unsigned int len, unsigned int off, unsigned int *copied)
Stefani Seibold86d48802009-12-21 14:37:32 -0800238{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700239 unsigned int l;
240 unsigned long ret;
241 unsigned int size = fifo->mask + 1;
242 unsigned int esize = fifo->esize;
Stefani Seibold86d48802009-12-21 14:37:32 -0800243
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700244 off &= fifo->mask;
245 if (esize != 1) {
246 off *= esize;
247 size *= esize;
248 len *= esize;
249 }
250 l = min(len, size - off);
251
252 ret = copy_to_user(to, fifo->data + off, l);
253 if (unlikely(ret))
254 ret = DIV_ROUND_UP(ret + len - l, esize);
255 else {
256 ret = copy_to_user(to + l, fifo->data, len - l);
257 if (unlikely(ret))
258 ret = DIV_ROUND_UP(ret, esize);
259 }
260 /*
261 * make sure that the data is copied before
262 * incrementing the fifo->out index counter
263 */
264 smp_wmb();
Lars-Peter Clausena019e482013-11-14 14:32:16 -0800265 *copied = len - ret * esize;
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700266 /* return the number of elements which are not copied */
267 return ret;
268}
269
270int __kfifo_to_user(struct __kfifo *fifo, void __user *to,
271 unsigned long len, unsigned int *copied)
272{
273 unsigned int l;
274 unsigned long ret;
275 unsigned int esize = fifo->esize;
276 int err;
277
278 if (esize != 1)
279 len /= esize;
280
281 l = fifo->in - fifo->out;
282 if (len > l)
283 len = l;
284 ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied);
285 if (unlikely(ret)) {
286 len -= ret;
287 err = -EFAULT;
288 } else
289 err = 0;
290 fifo->out += len;
291 return err;
292}
293EXPORT_SYMBOL(__kfifo_to_user);
294
295static int setup_sgl_buf(struct scatterlist *sgl, void *buf,
296 int nents, unsigned int len)
297{
298 int n;
299 unsigned int l;
300 unsigned int off;
301 struct page *page;
302
303 if (!nents)
304 return 0;
305
306 if (!len)
307 return 0;
308
309 n = 0;
310 page = virt_to_page(buf);
311 off = offset_in_page(buf);
312 l = 0;
313
314 while (len >= l + PAGE_SIZE - off) {
315 struct page *npage;
316
317 l += PAGE_SIZE;
318 buf += PAGE_SIZE;
319 npage = virt_to_page(buf);
320 if (page_to_phys(page) != page_to_phys(npage) - l) {
Stefani Seiboldd78a3ed2010-08-11 14:17:27 -0700321 sg_set_page(sgl, page, l - off, off);
322 sgl = sg_next(sgl);
323 if (++n == nents || sgl == NULL)
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700324 return n;
325 page = npage;
326 len -= l - off;
327 l = off = 0;
328 }
329 }
Stefani Seiboldd78a3ed2010-08-11 14:17:27 -0700330 sg_set_page(sgl, page, len, off);
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700331 return n + 1;
332}
333
334static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
335 int nents, unsigned int len, unsigned int off)
336{
337 unsigned int size = fifo->mask + 1;
338 unsigned int esize = fifo->esize;
339 unsigned int l;
340 unsigned int n;
341
342 off &= fifo->mask;
343 if (esize != 1) {
344 off *= esize;
345 size *= esize;
346 len *= esize;
347 }
348 l = min(len, size - off);
349
Stefani Seiboldd78a3ed2010-08-11 14:17:27 -0700350 n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700351 n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);
352
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700353 return n;
354}
355
356unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
357 struct scatterlist *sgl, int nents, unsigned int len)
358{
359 unsigned int l;
360
361 l = kfifo_unused(fifo);
362 if (len > l)
363 len = l;
364
365 return setup_sgl(fifo, sgl, nents, len, fifo->in);
366}
367EXPORT_SYMBOL(__kfifo_dma_in_prepare);
368
369unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
370 struct scatterlist *sgl, int nents, unsigned int len)
371{
372 unsigned int l;
373
374 l = fifo->in - fifo->out;
375 if (len > l)
376 len = l;
377
378 return setup_sgl(fifo, sgl, nents, len, fifo->out);
379}
380EXPORT_SYMBOL(__kfifo_dma_out_prepare);
381
382unsigned int __kfifo_max_r(unsigned int len, size_t recsize)
383{
384 unsigned int max = (1 << (recsize << 3)) - 1;
385
386 if (len > max)
387 return max;
388 return len;
389}
Srinivas Kandagatla30059d92012-04-11 05:01:56 -0300390EXPORT_SYMBOL(__kfifo_max_r);
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700391
392#define __KFIFO_PEEK(data, out, mask) \
393 ((data)[(out) & (mask)])
394/*
395 * __kfifo_peek_n internal helper function for determinate the length of
396 * the next record in the fifo
397 */
398static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize)
399{
400 unsigned int l;
401 unsigned int mask = fifo->mask;
402 unsigned char *data = fifo->data;
403
404 l = __KFIFO_PEEK(data, fifo->out, mask);
405
406 if (--recsize)
407 l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8;
408
409 return l;
410}
411
412#define __KFIFO_POKE(data, in, mask, val) \
413 ( \
414 (data)[(in) & (mask)] = (unsigned char)(val) \
415 )
416
417/*
Zhen Lei9dbbc3b2021-07-07 18:07:31 -0700418 * __kfifo_poke_n internal helper function for storing the length of
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700419 * the record into the fifo
420 */
421static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize)
422{
423 unsigned int mask = fifo->mask;
424 unsigned char *data = fifo->data;
425
426 __KFIFO_POKE(data, fifo->in, mask, n);
427
428 if (recsize > 1)
429 __KFIFO_POKE(data, fifo->in + 1, mask, n >> 8);
430}
431
432unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize)
433{
Stefani Seibold86d48802009-12-21 14:37:32 -0800434 return __kfifo_peek_n(fifo, recsize);
435}
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700436EXPORT_SYMBOL(__kfifo_len_r);
Stefani Seibold86d48802009-12-21 14:37:32 -0800437
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700438unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf,
439 unsigned int len, size_t recsize)
Stefani Seibold86d48802009-12-21 14:37:32 -0800440{
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700441 if (len + recsize > kfifo_unused(fifo))
442 return 0;
Stefani Seibold86d48802009-12-21 14:37:32 -0800443
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700444 __kfifo_poke_n(fifo, len, recsize);
445
446 kfifo_copy_in(fifo, buf, len, fifo->in + recsize);
447 fifo->in += len + recsize;
448 return len;
449}
450EXPORT_SYMBOL(__kfifo_in_r);
451
452static unsigned int kfifo_out_copy_r(struct __kfifo *fifo,
453 void *buf, unsigned int len, size_t recsize, unsigned int *n)
454{
455 *n = __kfifo_peek_n(fifo, recsize);
456
457 if (len > *n)
458 len = *n;
459
460 kfifo_copy_out(fifo, buf, len, fifo->out + recsize);
461 return len;
462}
463
464unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf,
465 unsigned int len, size_t recsize)
466{
467 unsigned int n;
468
469 if (fifo->in == fifo->out)
470 return 0;
471
472 return kfifo_out_copy_r(fifo, buf, len, recsize, &n);
473}
474EXPORT_SYMBOL(__kfifo_out_peek_r);
475
476unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,
477 unsigned int len, size_t recsize)
478{
479 unsigned int n;
480
481 if (fifo->in == fifo->out)
482 return 0;
483
484 len = kfifo_out_copy_r(fifo, buf, len, recsize, &n);
485 fifo->out += n + recsize;
486 return len;
487}
488EXPORT_SYMBOL(__kfifo_out_r);
489
Andrea Righib35de432010-08-19 14:13:27 -0700490void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize)
491{
492 unsigned int n;
493
494 n = __kfifo_peek_n(fifo, recsize);
495 fifo->out += n + recsize;
496}
497EXPORT_SYMBOL(__kfifo_skip_r);
498
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700499int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from,
500 unsigned long len, unsigned int *copied, size_t recsize)
501{
502 unsigned long ret;
503
504 len = __kfifo_max_r(len, recsize);
505
506 if (len + recsize > kfifo_unused(fifo)) {
507 *copied = 0;
508 return 0;
509 }
510
511 __kfifo_poke_n(fifo, len, recsize);
512
513 ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied);
514 if (unlikely(ret)) {
515 *copied = 0;
516 return -EFAULT;
517 }
518 fifo->in += len + recsize;
519 return 0;
520}
521EXPORT_SYMBOL(__kfifo_from_user_r);
522
523int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
524 unsigned long len, unsigned int *copied, size_t recsize)
525{
526 unsigned long ret;
527 unsigned int n;
528
529 if (fifo->in == fifo->out) {
530 *copied = 0;
531 return 0;
532 }
533
534 n = __kfifo_peek_n(fifo, recsize);
535 if (len > n)
536 len = n;
537
538 ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied);
539 if (unlikely(ret)) {
540 *copied = 0;
541 return -EFAULT;
542 }
543 fifo->out += n + recsize;
544 return 0;
545}
546EXPORT_SYMBOL(__kfifo_to_user_r);
547
548unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
549 struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
550{
Himangi Saraogi89b3ac62014-08-08 14:22:44 -0700551 BUG_ON(!nents);
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700552
553 len = __kfifo_max_r(len, recsize);
554
555 if (len + recsize > kfifo_unused(fifo))
556 return 0;
557
558 return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);
559}
560EXPORT_SYMBOL(__kfifo_dma_in_prepare_r);
561
562void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
563 unsigned int len, size_t recsize)
564{
565 len = __kfifo_max_r(len, recsize);
566 __kfifo_poke_n(fifo, len, recsize);
567 fifo->in += len + recsize;
568}
569EXPORT_SYMBOL(__kfifo_dma_in_finish_r);
570
571unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
572 struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
573{
Himangi Saraogi89b3ac62014-08-08 14:22:44 -0700574 BUG_ON(!nents);
Stefani Seibold2e956fb2010-08-10 18:03:38 -0700575
576 len = __kfifo_max_r(len, recsize);
577
578 if (len + recsize > fifo->in - fifo->out)
579 return 0;
580
581 return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);
582}
583EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);
584
585void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize)
586{
587 unsigned int len;
588
589 len = __kfifo_peek_n(fifo, recsize);
590 fifo->out += len + recsize;
591}
592EXPORT_SYMBOL(__kfifo_dma_out_finish_r);