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1da177e4 | 1 | /* |
45465487 | 2 | * A generic kernel FIFO implementation. |
1da177e4 | 3 | * |
45465487 | 4 | * Copyright (C) 2009 Stefani Seibold <stefani@seibold.net> |
1da177e4 LT |
5 | * Copyright (C) 2004 Stelian Pop <stelian@popies.net> |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
20 | * | |
21 | */ | |
7acd72eb SS |
22 | |
23 | /* | |
24 | * Howto porting drivers to the new generic fifo API: | |
25 | * | |
26 | * - Modify the declaration of the "struct kfifo *" object into a | |
27 | * in-place "struct kfifo" object | |
28 | * - Init the in-place object with kfifo_alloc() or kfifo_init() | |
29 | * Note: The address of the in-place "struct kfifo" object must be | |
30 | * passed as the first argument to this functions | |
31 | * - Replace the use of __kfifo_put into kfifo_in and __kfifo_get | |
32 | * into kfifo_out | |
33 | * - Replace the use of kfifo_put into kfifo_in_locked and kfifo_get | |
34 | * into kfifo_out_locked | |
35 | * Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc | |
36 | * must be passed now to the kfifo_in_locked and kfifo_out_locked | |
37 | * as the last parameter. | |
38 | * - All formerly name __kfifo_* functions has been renamed into kfifo_* | |
39 | */ | |
40 | ||
1da177e4 LT |
41 | #ifndef _LINUX_KFIFO_H |
42 | #define _LINUX_KFIFO_H | |
43 | ||
1da177e4 LT |
44 | #include <linux/kernel.h> |
45 | #include <linux/spinlock.h> | |
46 | ||
47 | struct kfifo { | |
48 | unsigned char *buffer; /* the buffer holding the data */ | |
49 | unsigned int size; /* the size of the allocated buffer */ | |
50 | unsigned int in; /* data is added at offset (in % size) */ | |
51 | unsigned int out; /* data is extracted from off. (out % size) */ | |
1da177e4 LT |
52 | }; |
53 | ||
37bdfbbf SS |
54 | /* |
55 | * Macros for declaration and initialization of the kfifo datatype | |
56 | */ | |
57 | ||
58 | /* helper macro */ | |
59 | #define __kfifo_initializer(s, b) \ | |
60 | (struct kfifo) { \ | |
61 | .size = s, \ | |
62 | .in = 0, \ | |
63 | .out = 0, \ | |
64 | .buffer = b \ | |
65 | } | |
66 | ||
67 | /** | |
68 | * DECLARE_KFIFO - macro to declare a kfifo and the associated buffer | |
69 | * @name: name of the declared kfifo datatype | |
70 | * @size: size of the fifo buffer | |
71 | * | |
9c717de9 RD |
72 | * Note1: the macro can be used inside struct or union declaration |
73 | * Note2: the macro creates two objects: | |
37bdfbbf SS |
74 | * A kfifo object with the given name and a buffer for the kfifo |
75 | * object named name##kfifo_buffer | |
76 | */ | |
77 | #define DECLARE_KFIFO(name, size) \ | |
78 | union { \ | |
79 | struct kfifo name; \ | |
80 | unsigned char name##kfifo_buffer[size + sizeof(struct kfifo)]; \ | |
81 | } | |
82 | ||
83 | /** | |
ed656d8d | 84 | * INIT_KFIFO - Initialize a kfifo declared by DECLARE_KFIFO |
37bdfbbf | 85 | * @name: name of the declared kfifo datatype |
37bdfbbf SS |
86 | */ |
87 | #define INIT_KFIFO(name) \ | |
88 | name = __kfifo_initializer(sizeof(name##kfifo_buffer) - \ | |
89 | sizeof(struct kfifo), name##kfifo_buffer) | |
90 | ||
91 | /** | |
92 | * DEFINE_KFIFO - macro to define and initialize a kfifo | |
93 | * @name: name of the declared kfifo datatype | |
94 | * @size: size of the fifo buffer | |
95 | * | |
9c717de9 RD |
96 | * Note1: the macro can be used for global and local kfifo data type variables |
97 | * Note2: the macro creates two objects: | |
37bdfbbf SS |
98 | * A kfifo object with the given name and a buffer for the kfifo |
99 | * object named name##kfifo_buffer | |
100 | */ | |
101 | #define DEFINE_KFIFO(name, size) \ | |
102 | unsigned char name##kfifo_buffer[size]; \ | |
103 | struct kfifo name = __kfifo_initializer(size, name##kfifo_buffer) | |
104 | ||
105 | #undef __kfifo_initializer | |
106 | ||
8ecc2951 | 107 | extern void kfifo_init(struct kfifo *fifo, void *buffer, |
c1e13f25 | 108 | unsigned int size); |
45465487 | 109 | extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size, |
c1e13f25 | 110 | gfp_t gfp_mask); |
1da177e4 | 111 | extern void kfifo_free(struct kfifo *fifo); |
9842c38e | 112 | extern unsigned int kfifo_in(struct kfifo *fifo, |
8ecc2951 | 113 | const void *from, unsigned int len); |
7acd72eb | 114 | extern __must_check unsigned int kfifo_out(struct kfifo *fifo, |
8ecc2951 | 115 | void *to, unsigned int len); |
1da177e4 | 116 | |
1da177e4 LT |
117 | /** |
118 | * kfifo_reset - removes the entire FIFO contents | |
119 | * @fifo: the fifo to be emptied. | |
120 | */ | |
121 | static inline void kfifo_reset(struct kfifo *fifo) | |
122 | { | |
e64c026d | 123 | fifo->in = fifo->out = 0; |
c1e13f25 SS |
124 | } |
125 | ||
a121f24a SS |
126 | /** |
127 | * kfifo_reset_out - skip FIFO contents | |
128 | * @fifo: the fifo to be emptied. | |
129 | */ | |
130 | static inline void kfifo_reset_out(struct kfifo *fifo) | |
131 | { | |
132 | smp_mb(); | |
133 | fifo->out = fifo->in; | |
134 | } | |
135 | ||
37bdfbbf SS |
136 | /** |
137 | * kfifo_size - returns the size of the fifo in bytes | |
138 | * @fifo: the fifo to be used. | |
139 | */ | |
140 | static inline __must_check unsigned int kfifo_size(struct kfifo *fifo) | |
141 | { | |
142 | return fifo->size; | |
143 | } | |
144 | ||
c1e13f25 | 145 | /** |
e64c026d | 146 | * kfifo_len - returns the number of used bytes in the FIFO |
c1e13f25 SS |
147 | * @fifo: the fifo to be used. |
148 | */ | |
e64c026d | 149 | static inline unsigned int kfifo_len(struct kfifo *fifo) |
c1e13f25 SS |
150 | { |
151 | register unsigned int out; | |
1da177e4 | 152 | |
c1e13f25 SS |
153 | out = fifo->out; |
154 | smp_rmb(); | |
155 | return fifo->in - out; | |
1da177e4 LT |
156 | } |
157 | ||
37bdfbbf SS |
158 | /** |
159 | * kfifo_is_empty - returns true if the fifo is empty | |
160 | * @fifo: the fifo to be used. | |
161 | */ | |
162 | static inline __must_check int kfifo_is_empty(struct kfifo *fifo) | |
163 | { | |
164 | return fifo->in == fifo->out; | |
165 | } | |
166 | ||
167 | /** | |
168 | * kfifo_is_full - returns true if the fifo is full | |
169 | * @fifo: the fifo to be used. | |
170 | */ | |
171 | static inline __must_check int kfifo_is_full(struct kfifo *fifo) | |
172 | { | |
173 | return kfifo_len(fifo) == kfifo_size(fifo); | |
174 | } | |
175 | ||
176 | /** | |
177 | * kfifo_avail - returns the number of bytes available in the FIFO | |
178 | * @fifo: the fifo to be used. | |
179 | */ | |
180 | static inline __must_check unsigned int kfifo_avail(struct kfifo *fifo) | |
181 | { | |
182 | return kfifo_size(fifo) - kfifo_len(fifo); | |
183 | } | |
184 | ||
1da177e4 | 185 | /** |
7acd72eb | 186 | * kfifo_in_locked - puts some data into the FIFO using a spinlock for locking |
1da177e4 | 187 | * @fifo: the fifo to be used. |
c1e13f25 SS |
188 | * @from: the data to be added. |
189 | * @n: the length of the data to be added. | |
190 | * @lock: pointer to the spinlock to use for locking. | |
1da177e4 | 191 | * |
c1e13f25 | 192 | * This function copies at most @len bytes from the @from buffer into |
1da177e4 LT |
193 | * the FIFO depending on the free space, and returns the number of |
194 | * bytes copied. | |
195 | */ | |
9842c38e | 196 | static inline unsigned int kfifo_in_locked(struct kfifo *fifo, |
8ecc2951 | 197 | const void *from, unsigned int n, spinlock_t *lock) |
1da177e4 LT |
198 | { |
199 | unsigned long flags; | |
200 | unsigned int ret; | |
201 | ||
c1e13f25 | 202 | spin_lock_irqsave(lock, flags); |
1da177e4 | 203 | |
7acd72eb | 204 | ret = kfifo_in(fifo, from, n); |
1da177e4 | 205 | |
c1e13f25 | 206 | spin_unlock_irqrestore(lock, flags); |
1da177e4 LT |
207 | |
208 | return ret; | |
209 | } | |
210 | ||
211 | /** | |
7acd72eb | 212 | * kfifo_out_locked - gets some data from the FIFO using a spinlock for locking |
1da177e4 | 213 | * @fifo: the fifo to be used. |
c1e13f25 SS |
214 | * @to: where the data must be copied. |
215 | * @n: the size of the destination buffer. | |
216 | * @lock: pointer to the spinlock to use for locking. | |
1da177e4 | 217 | * |
72fd4a35 | 218 | * This function copies at most @len bytes from the FIFO into the |
c1e13f25 | 219 | * @to buffer and returns the number of copied bytes. |
1da177e4 | 220 | */ |
7acd72eb | 221 | static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo, |
8ecc2951 | 222 | void *to, unsigned int n, spinlock_t *lock) |
1da177e4 LT |
223 | { |
224 | unsigned long flags; | |
225 | unsigned int ret; | |
226 | ||
c1e13f25 | 227 | spin_lock_irqsave(lock, flags); |
1da177e4 | 228 | |
7acd72eb | 229 | ret = kfifo_out(fifo, to, n); |
1da177e4 | 230 | |
c1e13f25 | 231 | spin_unlock_irqrestore(lock, flags); |
1da177e4 LT |
232 | |
233 | return ret; | |
234 | } | |
235 | ||
a121f24a SS |
236 | extern void kfifo_skip(struct kfifo *fifo, unsigned int len); |
237 | ||
64ce1037 AK |
238 | extern __must_check int kfifo_from_user(struct kfifo *fifo, |
239 | const void __user *from, unsigned int n, unsigned *lenout); | |
a121f24a | 240 | |
64ce1037 AK |
241 | extern __must_check int kfifo_to_user(struct kfifo *fifo, |
242 | void __user *to, unsigned int n, unsigned *lenout); | |
a121f24a | 243 | |
9c717de9 | 244 | /* |
a121f24a SS |
245 | * __kfifo_add_out internal helper function for updating the out offset |
246 | */ | |
247 | static inline void __kfifo_add_out(struct kfifo *fifo, | |
248 | unsigned int off) | |
249 | { | |
250 | smp_mb(); | |
251 | fifo->out += off; | |
252 | } | |
253 | ||
9c717de9 | 254 | /* |
a121f24a SS |
255 | * __kfifo_add_in internal helper function for updating the in offset |
256 | */ | |
257 | static inline void __kfifo_add_in(struct kfifo *fifo, | |
258 | unsigned int off) | |
259 | { | |
260 | smp_wmb(); | |
261 | fifo->in += off; | |
262 | } | |
263 | ||
9c717de9 | 264 | /* |
a121f24a SS |
265 | * __kfifo_off internal helper function for calculating the index of a |
266 | * given offeset | |
267 | */ | |
268 | static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off) | |
269 | { | |
270 | return off & (fifo->size - 1); | |
271 | } | |
272 | ||
9c717de9 | 273 | /* |
86d48803 SS |
274 | * __kfifo_peek_n internal helper function for determinate the length of |
275 | * the next record in the fifo | |
276 | */ | |
277 | static inline unsigned int __kfifo_peek_n(struct kfifo *fifo, | |
278 | unsigned int recsize) | |
279 | { | |
280 | #define __KFIFO_GET(fifo, off, shift) \ | |
281 | ((fifo)->buffer[__kfifo_off((fifo), (fifo)->out+(off))] << (shift)) | |
282 | ||
283 | unsigned int l; | |
284 | ||
285 | l = __KFIFO_GET(fifo, 0, 0); | |
286 | ||
287 | if (--recsize) | |
288 | l |= __KFIFO_GET(fifo, 1, 8); | |
289 | ||
290 | return l; | |
291 | #undef __KFIFO_GET | |
292 | } | |
293 | ||
9c717de9 | 294 | /* |
86d48803 SS |
295 | * __kfifo_poke_n internal helper function for storing the length of |
296 | * the next record into the fifo | |
297 | */ | |
298 | static inline void __kfifo_poke_n(struct kfifo *fifo, | |
299 | unsigned int recsize, unsigned int n) | |
300 | { | |
301 | #define __KFIFO_PUT(fifo, off, val, shift) \ | |
302 | ( \ | |
303 | (fifo)->buffer[__kfifo_off((fifo), (fifo)->in+(off))] = \ | |
304 | (unsigned char)((val) >> (shift)) \ | |
305 | ) | |
306 | ||
307 | __KFIFO_PUT(fifo, 0, n, 0); | |
308 | ||
309 | if (--recsize) | |
310 | __KFIFO_PUT(fifo, 1, n, 8); | |
311 | #undef __KFIFO_PUT | |
312 | } | |
313 | ||
9c717de9 | 314 | /* |
86d48803 SS |
315 | * __kfifo_in_... internal functions for put date into the fifo |
316 | * do not call it directly, use kfifo_in_rec() instead | |
317 | */ | |
318 | extern unsigned int __kfifo_in_n(struct kfifo *fifo, | |
319 | const void *from, unsigned int n, unsigned int recsize); | |
320 | ||
321 | extern unsigned int __kfifo_in_generic(struct kfifo *fifo, | |
322 | const void *from, unsigned int n, unsigned int recsize); | |
323 | ||
324 | static inline unsigned int __kfifo_in_rec(struct kfifo *fifo, | |
325 | const void *from, unsigned int n, unsigned int recsize) | |
326 | { | |
327 | unsigned int ret; | |
328 | ||
329 | ret = __kfifo_in_n(fifo, from, n, recsize); | |
330 | ||
331 | if (likely(ret == 0)) { | |
332 | if (recsize) | |
333 | __kfifo_poke_n(fifo, recsize, n); | |
334 | __kfifo_add_in(fifo, n + recsize); | |
335 | } | |
336 | return ret; | |
337 | } | |
338 | ||
339 | /** | |
340 | * kfifo_in_rec - puts some record data into the FIFO | |
341 | * @fifo: the fifo to be used. | |
342 | * @from: the data to be added. | |
343 | * @n: the length of the data to be added. | |
344 | * @recsize: size of record field | |
345 | * | |
346 | * This function copies @n bytes from the @from into the FIFO and returns | |
347 | * the number of bytes which cannot be copied. | |
348 | * A returned value greater than the @n value means that the record doesn't | |
349 | * fit into the buffer. | |
350 | * | |
351 | * Note that with only one concurrent reader and one concurrent | |
352 | * writer, you don't need extra locking to use these functions. | |
353 | */ | |
354 | static inline __must_check unsigned int kfifo_in_rec(struct kfifo *fifo, | |
355 | void *from, unsigned int n, unsigned int recsize) | |
356 | { | |
357 | if (!__builtin_constant_p(recsize)) | |
358 | return __kfifo_in_generic(fifo, from, n, recsize); | |
359 | return __kfifo_in_rec(fifo, from, n, recsize); | |
360 | } | |
361 | ||
9c717de9 | 362 | /* |
86d48803 SS |
363 | * __kfifo_out_... internal functions for get date from the fifo |
364 | * do not call it directly, use kfifo_out_rec() instead | |
365 | */ | |
366 | extern unsigned int __kfifo_out_n(struct kfifo *fifo, | |
367 | void *to, unsigned int reclen, unsigned int recsize); | |
368 | ||
369 | extern unsigned int __kfifo_out_generic(struct kfifo *fifo, | |
370 | void *to, unsigned int n, | |
371 | unsigned int recsize, unsigned int *total); | |
372 | ||
373 | static inline unsigned int __kfifo_out_rec(struct kfifo *fifo, | |
374 | void *to, unsigned int n, unsigned int recsize, | |
375 | unsigned int *total) | |
376 | { | |
377 | unsigned int l; | |
378 | ||
379 | if (!recsize) { | |
380 | l = n; | |
381 | if (total) | |
382 | *total = l; | |
383 | } else { | |
384 | l = __kfifo_peek_n(fifo, recsize); | |
385 | if (total) | |
386 | *total = l; | |
387 | if (n < l) | |
388 | return l; | |
389 | } | |
390 | ||
391 | return __kfifo_out_n(fifo, to, l, recsize); | |
392 | } | |
393 | ||
394 | /** | |
395 | * kfifo_out_rec - gets some record data from the FIFO | |
396 | * @fifo: the fifo to be used. | |
397 | * @to: where the data must be copied. | |
398 | * @n: the size of the destination buffer. | |
399 | * @recsize: size of record field | |
400 | * @total: pointer where the total number of to copied bytes should stored | |
401 | * | |
402 | * This function copies at most @n bytes from the FIFO to @to and returns the | |
403 | * number of bytes which cannot be copied. | |
404 | * A returned value greater than the @n value means that the record doesn't | |
405 | * fit into the @to buffer. | |
406 | * | |
407 | * Note that with only one concurrent reader and one concurrent | |
408 | * writer, you don't need extra locking to use these functions. | |
409 | */ | |
410 | static inline __must_check unsigned int kfifo_out_rec(struct kfifo *fifo, | |
411 | void *to, unsigned int n, unsigned int recsize, | |
412 | unsigned int *total) | |
413 | ||
414 | { | |
415 | if (!__builtin_constant_p(recsize)) | |
416 | return __kfifo_out_generic(fifo, to, n, recsize, total); | |
417 | return __kfifo_out_rec(fifo, to, n, recsize, total); | |
418 | } | |
419 | ||
9c717de9 | 420 | /* |
86d48803 SS |
421 | * __kfifo_from_user_... internal functions for transfer from user space into |
422 | * the fifo. do not call it directly, use kfifo_from_user_rec() instead | |
423 | */ | |
424 | extern unsigned int __kfifo_from_user_n(struct kfifo *fifo, | |
425 | const void __user *from, unsigned int n, unsigned int recsize); | |
426 | ||
427 | extern unsigned int __kfifo_from_user_generic(struct kfifo *fifo, | |
428 | const void __user *from, unsigned int n, unsigned int recsize); | |
429 | ||
430 | static inline unsigned int __kfifo_from_user_rec(struct kfifo *fifo, | |
431 | const void __user *from, unsigned int n, unsigned int recsize) | |
432 | { | |
433 | unsigned int ret; | |
434 | ||
435 | ret = __kfifo_from_user_n(fifo, from, n, recsize); | |
436 | ||
437 | if (likely(ret == 0)) { | |
438 | if (recsize) | |
439 | __kfifo_poke_n(fifo, recsize, n); | |
440 | __kfifo_add_in(fifo, n + recsize); | |
441 | } | |
442 | return ret; | |
443 | } | |
444 | ||
445 | /** | |
446 | * kfifo_from_user_rec - puts some data from user space into the FIFO | |
447 | * @fifo: the fifo to be used. | |
448 | * @from: pointer to the data to be added. | |
449 | * @n: the length of the data to be added. | |
450 | * @recsize: size of record field | |
451 | * | |
452 | * This function copies @n bytes from the @from into the | |
453 | * FIFO and returns the number of bytes which cannot be copied. | |
454 | * | |
455 | * If the returned value is equal or less the @n value, the copy_from_user() | |
456 | * functions has failed. Otherwise the record doesn't fit into the buffer. | |
457 | * | |
458 | * Note that with only one concurrent reader and one concurrent | |
459 | * writer, you don't need extra locking to use these functions. | |
460 | */ | |
461 | static inline __must_check unsigned int kfifo_from_user_rec(struct kfifo *fifo, | |
462 | const void __user *from, unsigned int n, unsigned int recsize) | |
463 | { | |
464 | if (!__builtin_constant_p(recsize)) | |
465 | return __kfifo_from_user_generic(fifo, from, n, recsize); | |
466 | return __kfifo_from_user_rec(fifo, from, n, recsize); | |
467 | } | |
468 | ||
9c717de9 | 469 | /* |
86d48803 SS |
470 | * __kfifo_to_user_... internal functions for transfer fifo data into user space |
471 | * do not call it directly, use kfifo_to_user_rec() instead | |
472 | */ | |
473 | extern unsigned int __kfifo_to_user_n(struct kfifo *fifo, | |
474 | void __user *to, unsigned int n, unsigned int reclen, | |
475 | unsigned int recsize); | |
476 | ||
477 | extern unsigned int __kfifo_to_user_generic(struct kfifo *fifo, | |
478 | void __user *to, unsigned int n, unsigned int recsize, | |
479 | unsigned int *total); | |
480 | ||
481 | static inline unsigned int __kfifo_to_user_rec(struct kfifo *fifo, | |
482 | void __user *to, unsigned int n, | |
483 | unsigned int recsize, unsigned int *total) | |
484 | { | |
485 | unsigned int l; | |
486 | ||
487 | if (!recsize) { | |
488 | l = n; | |
489 | if (total) | |
490 | *total = l; | |
491 | } else { | |
492 | l = __kfifo_peek_n(fifo, recsize); | |
493 | if (total) | |
494 | *total = l; | |
495 | if (n < l) | |
496 | return l; | |
497 | } | |
498 | ||
499 | return __kfifo_to_user_n(fifo, to, n, l, recsize); | |
500 | } | |
501 | ||
502 | /** | |
503 | * kfifo_to_user_rec - gets data from the FIFO and write it to user space | |
504 | * @fifo: the fifo to be used. | |
505 | * @to: where the data must be copied. | |
506 | * @n: the size of the destination buffer. | |
507 | * @recsize: size of record field | |
508 | * @total: pointer where the total number of to copied bytes should stored | |
509 | * | |
510 | * This function copies at most @n bytes from the FIFO to the @to. | |
511 | * In case of an error, the function returns the number of bytes which cannot | |
512 | * be copied. | |
513 | * If the returned value is equal or less the @n value, the copy_to_user() | |
514 | * functions has failed. Otherwise the record doesn't fit into the @to buffer. | |
515 | * | |
516 | * Note that with only one concurrent reader and one concurrent | |
517 | * writer, you don't need extra locking to use these functions. | |
518 | */ | |
519 | static inline __must_check unsigned int kfifo_to_user_rec(struct kfifo *fifo, | |
520 | void __user *to, unsigned int n, unsigned int recsize, | |
521 | unsigned int *total) | |
522 | { | |
523 | if (!__builtin_constant_p(recsize)) | |
524 | return __kfifo_to_user_generic(fifo, to, n, recsize, total); | |
525 | return __kfifo_to_user_rec(fifo, to, n, recsize, total); | |
526 | } | |
527 | ||
9c717de9 | 528 | /* |
86d48803 SS |
529 | * __kfifo_peek_... internal functions for peek into the next fifo record |
530 | * do not call it directly, use kfifo_peek_rec() instead | |
531 | */ | |
532 | extern unsigned int __kfifo_peek_generic(struct kfifo *fifo, | |
533 | unsigned int recsize); | |
534 | ||
535 | /** | |
536 | * kfifo_peek_rec - gets the size of the next FIFO record data | |
537 | * @fifo: the fifo to be used. | |
538 | * @recsize: size of record field | |
539 | * | |
540 | * This function returns the size of the next FIFO record in number of bytes | |
541 | */ | |
542 | static inline __must_check unsigned int kfifo_peek_rec(struct kfifo *fifo, | |
543 | unsigned int recsize) | |
544 | { | |
545 | if (!__builtin_constant_p(recsize)) | |
546 | return __kfifo_peek_generic(fifo, recsize); | |
547 | if (!recsize) | |
548 | return kfifo_len(fifo); | |
549 | return __kfifo_peek_n(fifo, recsize); | |
550 | } | |
551 | ||
9c717de9 | 552 | /* |
86d48803 SS |
553 | * __kfifo_skip_... internal functions for skip the next fifo record |
554 | * do not call it directly, use kfifo_skip_rec() instead | |
555 | */ | |
556 | extern void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize); | |
557 | ||
558 | static inline void __kfifo_skip_rec(struct kfifo *fifo, | |
559 | unsigned int recsize) | |
560 | { | |
561 | unsigned int l; | |
562 | ||
563 | if (recsize) { | |
564 | l = __kfifo_peek_n(fifo, recsize); | |
565 | ||
566 | if (l + recsize <= kfifo_len(fifo)) { | |
567 | __kfifo_add_out(fifo, l + recsize); | |
568 | return; | |
569 | } | |
570 | } | |
571 | kfifo_reset_out(fifo); | |
572 | } | |
573 | ||
574 | /** | |
575 | * kfifo_skip_rec - skip the next fifo out record | |
576 | * @fifo: the fifo to be used. | |
577 | * @recsize: size of record field | |
578 | * | |
579 | * This function skips the next FIFO record | |
580 | */ | |
581 | static inline void kfifo_skip_rec(struct kfifo *fifo, | |
582 | unsigned int recsize) | |
583 | { | |
584 | if (!__builtin_constant_p(recsize)) | |
585 | __kfifo_skip_generic(fifo, recsize); | |
586 | else | |
587 | __kfifo_skip_rec(fifo, recsize); | |
588 | } | |
589 | ||
590 | /** | |
591 | * kfifo_avail_rec - returns the number of bytes available in a record FIFO | |
592 | * @fifo: the fifo to be used. | |
593 | * @recsize: size of record field | |
594 | */ | |
595 | static inline __must_check unsigned int kfifo_avail_rec(struct kfifo *fifo, | |
596 | unsigned int recsize) | |
597 | { | |
598 | unsigned int l = kfifo_size(fifo) - kfifo_len(fifo); | |
599 | ||
600 | return (l > recsize) ? l - recsize : 0; | |
601 | } | |
602 | ||
1da177e4 | 603 | #endif |