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TOMOYO Linux Cross Reference
Linux/include/linux/kfifo.h

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Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * A generic kernel FIFO implementation
  3  *
  4  * Copyright (C) 2013 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 #ifndef _LINUX_KFIFO_H
 23 #define _LINUX_KFIFO_H
 24 
 25 /*
 26  * How to porting drivers to the new generic FIFO API:
 27  *
 28  * - Modify the declaration of the "struct kfifo *" object into a
 29  *   in-place "struct kfifo" object
 30  * - Init the in-place object with kfifo_alloc() or kfifo_init()
 31  *   Note: The address of the in-place "struct kfifo" object must be
 32  *   passed as the first argument to this functions
 33  * - Replace the use of __kfifo_put into kfifo_in and __kfifo_get
 34  *   into kfifo_out
 35  * - Replace the use of kfifo_put into kfifo_in_spinlocked and kfifo_get
 36  *   into kfifo_out_spinlocked
 37  *   Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc
 38  *   must be passed now to the kfifo_in_spinlocked and kfifo_out_spinlocked
 39  *   as the last parameter
 40  * - The formerly __kfifo_* functions are renamed into kfifo_*
 41  */
 42 
 43 /*
 44  * Note about locking : There is no locking required until only * one reader
 45  * and one writer is using the fifo and no kfifo_reset() will be * called
 46  *  kfifo_reset_out() can be safely used, until it will be only called
 47  * in the reader thread.
 48  *  For multiple writer and one reader there is only a need to lock the writer.
 49  * And vice versa for only one writer and multiple reader there is only a need
 50  * to lock the reader.
 51  */
 52 
 53 #include <linux/kernel.h>
 54 #include <linux/spinlock.h>
 55 #include <linux/stddef.h>
 56 #include <linux/scatterlist.h>
 57 
 58 struct __kfifo {
 59         unsigned int    in;
 60         unsigned int    out;
 61         unsigned int    mask;
 62         unsigned int    esize;
 63         void            *data;
 64 };
 65 
 66 #define __STRUCT_KFIFO_COMMON(datatype, recsize, ptrtype) \
 67         union { \
 68                 struct __kfifo  kfifo; \
 69                 datatype        *type; \
 70                 const datatype  *const_type; \
 71                 char            (*rectype)[recsize]; \
 72                 ptrtype         *ptr; \
 73                 ptrtype const   *ptr_const; \
 74         }
 75 
 76 #define __STRUCT_KFIFO(type, size, recsize, ptrtype) \
 77 { \
 78         __STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
 79         type            buf[((size < 2) || (size & (size - 1))) ? -1 : size]; \
 80 }
 81 
 82 #define STRUCT_KFIFO(type, size) \
 83         struct __STRUCT_KFIFO(type, size, 0, type)
 84 
 85 #define __STRUCT_KFIFO_PTR(type, recsize, ptrtype) \
 86 { \
 87         __STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
 88         type            buf[0]; \
 89 }
 90 
 91 #define STRUCT_KFIFO_PTR(type) \
 92         struct __STRUCT_KFIFO_PTR(type, 0, type)
 93 
 94 /*
 95  * define compatibility "struct kfifo" for dynamic allocated fifos
 96  */
 97 struct kfifo __STRUCT_KFIFO_PTR(unsigned char, 0, void);
 98 
 99 #define STRUCT_KFIFO_REC_1(size) \
100         struct __STRUCT_KFIFO(unsigned char, size, 1, void)
101 
102 #define STRUCT_KFIFO_REC_2(size) \
103         struct __STRUCT_KFIFO(unsigned char, size, 2, void)
104 
105 /*
106  * define kfifo_rec types
107  */
108 struct kfifo_rec_ptr_1 __STRUCT_KFIFO_PTR(unsigned char, 1, void);
109 struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR(unsigned char, 2, void);
110 
111 /*
112  * helper macro to distinguish between real in place fifo where the fifo
113  * array is a part of the structure and the fifo type where the array is
114  * outside of the fifo structure.
115  */
116 #define __is_kfifo_ptr(fifo)    (sizeof(*fifo) == sizeof(struct __kfifo))
117 
118 /**
119  * DECLARE_KFIFO_PTR - macro to declare a fifo pointer object
120  * @fifo: name of the declared fifo
121  * @type: type of the fifo elements
122  */
123 #define DECLARE_KFIFO_PTR(fifo, type)   STRUCT_KFIFO_PTR(type) fifo
124 
125 /**
126  * DECLARE_KFIFO - macro to declare a fifo object
127  * @fifo: name of the declared fifo
128  * @type: type of the fifo elements
129  * @size: the number of elements in the fifo, this must be a power of 2
130  */
131 #define DECLARE_KFIFO(fifo, type, size) STRUCT_KFIFO(type, size) fifo
132 
133 /**
134  * INIT_KFIFO - Initialize a fifo declared by DECLARE_KFIFO
135  * @fifo: name of the declared fifo datatype
136  */
137 #define INIT_KFIFO(fifo) \
138 (void)({ \
139         typeof(&(fifo)) __tmp = &(fifo); \
140         struct __kfifo *__kfifo = &__tmp->kfifo; \
141         __kfifo->in = 0; \
142         __kfifo->out = 0; \
143         __kfifo->mask = __is_kfifo_ptr(__tmp) ? 0 : ARRAY_SIZE(__tmp->buf) - 1;\
144         __kfifo->esize = sizeof(*__tmp->buf); \
145         __kfifo->data = __is_kfifo_ptr(__tmp) ?  NULL : __tmp->buf; \
146 })
147 
148 /**
149  * DEFINE_KFIFO - macro to define and initialize a fifo
150  * @fifo: name of the declared fifo datatype
151  * @type: type of the fifo elements
152  * @size: the number of elements in the fifo, this must be a power of 2
153  *
154  * Note: the macro can be used for global and local fifo data type variables.
155  */
156 #define DEFINE_KFIFO(fifo, type, size) \
157         DECLARE_KFIFO(fifo, type, size) = \
158         (typeof(fifo)) { \
159                 { \
160                         { \
161                         .in     = 0, \
162                         .out    = 0, \
163                         .mask   = __is_kfifo_ptr(&(fifo)) ? \
164                                   0 : \
165                                   ARRAY_SIZE((fifo).buf) - 1, \
166                         .esize  = sizeof(*(fifo).buf), \
167                         .data   = __is_kfifo_ptr(&(fifo)) ? \
168                                 NULL : \
169                                 (fifo).buf, \
170                         } \
171                 } \
172         }
173 
174 
175 static inline unsigned int __must_check
176 __kfifo_uint_must_check_helper(unsigned int val)
177 {
178         return val;
179 }
180 
181 static inline int __must_check
182 __kfifo_int_must_check_helper(int val)
183 {
184         return val;
185 }
186 
187 /**
188  * kfifo_initialized - Check if the fifo is initialized
189  * @fifo: address of the fifo to check
190  *
191  * Return %true if fifo is initialized, otherwise %false.
192  * Assumes the fifo was 0 before.
193  */
194 #define kfifo_initialized(fifo) ((fifo)->kfifo.mask)
195 
196 /**
197  * kfifo_esize - returns the size of the element managed by the fifo
198  * @fifo: address of the fifo to be used
199  */
200 #define kfifo_esize(fifo)       ((fifo)->kfifo.esize)
201 
202 /**
203  * kfifo_recsize - returns the size of the record length field
204  * @fifo: address of the fifo to be used
205  */
206 #define kfifo_recsize(fifo)     (sizeof(*(fifo)->rectype))
207 
208 /**
209  * kfifo_size - returns the size of the fifo in elements
210  * @fifo: address of the fifo to be used
211  */
212 #define kfifo_size(fifo)        ((fifo)->kfifo.mask + 1)
213 
214 /**
215  * kfifo_reset - removes the entire fifo content
216  * @fifo: address of the fifo to be used
217  *
218  * Note: usage of kfifo_reset() is dangerous. It should be only called when the
219  * fifo is exclusived locked or when it is secured that no other thread is
220  * accessing the fifo.
221  */
222 #define kfifo_reset(fifo) \
223 (void)({ \
224         typeof((fifo) + 1) __tmp = (fifo); \
225         __tmp->kfifo.in = __tmp->kfifo.out = 0; \
226 })
227 
228 /**
229  * kfifo_reset_out - skip fifo content
230  * @fifo: address of the fifo to be used
231  *
232  * Note: The usage of kfifo_reset_out() is safe until it will be only called
233  * from the reader thread and there is only one concurrent reader. Otherwise
234  * it is dangerous and must be handled in the same way as kfifo_reset().
235  */
236 #define kfifo_reset_out(fifo)   \
237 (void)({ \
238         typeof((fifo) + 1) __tmp = (fifo); \
239         __tmp->kfifo.out = __tmp->kfifo.in; \
240 })
241 
242 /**
243  * kfifo_len - returns the number of used elements in the fifo
244  * @fifo: address of the fifo to be used
245  */
246 #define kfifo_len(fifo) \
247 ({ \
248         typeof((fifo) + 1) __tmpl = (fifo); \
249         __tmpl->kfifo.in - __tmpl->kfifo.out; \
250 })
251 
252 /**
253  * kfifo_is_empty - returns true if the fifo is empty
254  * @fifo: address of the fifo to be used
255  */
256 #define kfifo_is_empty(fifo) \
257 ({ \
258         typeof((fifo) + 1) __tmpq = (fifo); \
259         __tmpq->kfifo.in == __tmpq->kfifo.out; \
260 })
261 
262 /**
263  * kfifo_is_full - returns true if the fifo is full
264  * @fifo: address of the fifo to be used
265  */
266 #define kfifo_is_full(fifo) \
267 ({ \
268         typeof((fifo) + 1) __tmpq = (fifo); \
269         kfifo_len(__tmpq) > __tmpq->kfifo.mask; \
270 })
271 
272 /**
273  * kfifo_avail - returns the number of unused elements in the fifo
274  * @fifo: address of the fifo to be used
275  */
276 #define kfifo_avail(fifo) \
277 __kfifo_uint_must_check_helper( \
278 ({ \
279         typeof((fifo) + 1) __tmpq = (fifo); \
280         const size_t __recsize = sizeof(*__tmpq->rectype); \
281         unsigned int __avail = kfifo_size(__tmpq) - kfifo_len(__tmpq); \
282         (__recsize) ? ((__avail <= __recsize) ? 0 : \
283         __kfifo_max_r(__avail - __recsize, __recsize)) : \
284         __avail; \
285 }) \
286 )
287 
288 /**
289  * kfifo_skip - skip output data
290  * @fifo: address of the fifo to be used
291  */
292 #define kfifo_skip(fifo) \
293 (void)({ \
294         typeof((fifo) + 1) __tmp = (fifo); \
295         const size_t __recsize = sizeof(*__tmp->rectype); \
296         struct __kfifo *__kfifo = &__tmp->kfifo; \
297         if (__recsize) \
298                 __kfifo_skip_r(__kfifo, __recsize); \
299         else \
300                 __kfifo->out++; \
301 })
302 
303 /**
304  * kfifo_peek_len - gets the size of the next fifo record
305  * @fifo: address of the fifo to be used
306  *
307  * This function returns the size of the next fifo record in number of bytes.
308  */
309 #define kfifo_peek_len(fifo) \
310 __kfifo_uint_must_check_helper( \
311 ({ \
312         typeof((fifo) + 1) __tmp = (fifo); \
313         const size_t __recsize = sizeof(*__tmp->rectype); \
314         struct __kfifo *__kfifo = &__tmp->kfifo; \
315         (!__recsize) ? kfifo_len(__tmp) * sizeof(*__tmp->type) : \
316         __kfifo_len_r(__kfifo, __recsize); \
317 }) \
318 )
319 
320 /**
321  * kfifo_alloc - dynamically allocates a new fifo buffer
322  * @fifo: pointer to the fifo
323  * @size: the number of elements in the fifo, this must be a power of 2
324  * @gfp_mask: get_free_pages mask, passed to kmalloc()
325  *
326  * This macro dynamically allocates a new fifo buffer.
327  *
328  * The numer of elements will be rounded-up to a power of 2.
329  * The fifo will be release with kfifo_free().
330  * Return 0 if no error, otherwise an error code.
331  */
332 #define kfifo_alloc(fifo, size, gfp_mask) \
333 __kfifo_int_must_check_helper( \
334 ({ \
335         typeof((fifo) + 1) __tmp = (fifo); \
336         struct __kfifo *__kfifo = &__tmp->kfifo; \
337         __is_kfifo_ptr(__tmp) ? \
338         __kfifo_alloc(__kfifo, size, sizeof(*__tmp->type), gfp_mask) : \
339         -EINVAL; \
340 }) \
341 )
342 
343 /**
344  * kfifo_free - frees the fifo
345  * @fifo: the fifo to be freed
346  */
347 #define kfifo_free(fifo) \
348 ({ \
349         typeof((fifo) + 1) __tmp = (fifo); \
350         struct __kfifo *__kfifo = &__tmp->kfifo; \
351         if (__is_kfifo_ptr(__tmp)) \
352                 __kfifo_free(__kfifo); \
353 })
354 
355 /**
356  * kfifo_init - initialize a fifo using a preallocated buffer
357  * @fifo: the fifo to assign the buffer
358  * @buffer: the preallocated buffer to be used
359  * @size: the size of the internal buffer, this have to be a power of 2
360  *
361  * This macro initialize a fifo using a preallocated buffer.
362  *
363  * The numer of elements will be rounded-up to a power of 2.
364  * Return 0 if no error, otherwise an error code.
365  */
366 #define kfifo_init(fifo, buffer, size) \
367 ({ \
368         typeof((fifo) + 1) __tmp = (fifo); \
369         struct __kfifo *__kfifo = &__tmp->kfifo; \
370         __is_kfifo_ptr(__tmp) ? \
371         __kfifo_init(__kfifo, buffer, size, sizeof(*__tmp->type)) : \
372         -EINVAL; \
373 })
374 
375 /**
376  * kfifo_put - put data into the fifo
377  * @fifo: address of the fifo to be used
378  * @val: the data to be added
379  *
380  * This macro copies the given value into the fifo.
381  * It returns 0 if the fifo was full. Otherwise it returns the number
382  * processed elements.
383  *
384  * Note that with only one concurrent reader and one concurrent
385  * writer, you don't need extra locking to use these macro.
386  */
387 #define kfifo_put(fifo, val) \
388 ({ \
389         typeof((fifo) + 1) __tmp = (fifo); \
390         typeof(*__tmp->const_type) __val = (val); \
391         unsigned int __ret; \
392         size_t __recsize = sizeof(*__tmp->rectype); \
393         struct __kfifo *__kfifo = &__tmp->kfifo; \
394         if (__recsize) \
395                 __ret = __kfifo_in_r(__kfifo, &__val, sizeof(__val), \
396                         __recsize); \
397         else { \
398                 __ret = !kfifo_is_full(__tmp); \
399                 if (__ret) { \
400                         (__is_kfifo_ptr(__tmp) ? \
401                         ((typeof(__tmp->type))__kfifo->data) : \
402                         (__tmp->buf) \
403                         )[__kfifo->in & __tmp->kfifo.mask] = \
404                                 *(typeof(__tmp->type))&__val; \
405                         smp_wmb(); \
406                         __kfifo->in++; \
407                 } \
408         } \
409         __ret; \
410 })
411 
412 /**
413  * kfifo_get - get data from the fifo
414  * @fifo: address of the fifo to be used
415  * @val: address where to store the data
416  *
417  * This macro reads the data from the fifo.
418  * It returns 0 if the fifo was empty. Otherwise it returns the number
419  * processed elements.
420  *
421  * Note that with only one concurrent reader and one concurrent
422  * writer, you don't need extra locking to use these macro.
423  */
424 #define kfifo_get(fifo, val) \
425 __kfifo_uint_must_check_helper( \
426 ({ \
427         typeof((fifo) + 1) __tmp = (fifo); \
428         typeof(__tmp->ptr) __val = (val); \
429         unsigned int __ret; \
430         const size_t __recsize = sizeof(*__tmp->rectype); \
431         struct __kfifo *__kfifo = &__tmp->kfifo; \
432         if (__recsize) \
433                 __ret = __kfifo_out_r(__kfifo, __val, sizeof(*__val), \
434                         __recsize); \
435         else { \
436                 __ret = !kfifo_is_empty(__tmp); \
437                 if (__ret) { \
438                         *(typeof(__tmp->type))__val = \
439                                 (__is_kfifo_ptr(__tmp) ? \
440                                 ((typeof(__tmp->type))__kfifo->data) : \
441                                 (__tmp->buf) \
442                                 )[__kfifo->out & __tmp->kfifo.mask]; \
443                         smp_wmb(); \
444                         __kfifo->out++; \
445                 } \
446         } \
447         __ret; \
448 }) \
449 )
450 
451 /**
452  * kfifo_peek - get data from the fifo without removing
453  * @fifo: address of the fifo to be used
454  * @val: address where to store the data
455  *
456  * This reads the data from the fifo without removing it from the fifo.
457  * It returns 0 if the fifo was empty. Otherwise it returns the number
458  * processed elements.
459  *
460  * Note that with only one concurrent reader and one concurrent
461  * writer, you don't need extra locking to use these macro.
462  */
463 #define kfifo_peek(fifo, val) \
464 __kfifo_uint_must_check_helper( \
465 ({ \
466         typeof((fifo) + 1) __tmp = (fifo); \
467         typeof(__tmp->ptr) __val = (val); \
468         unsigned int __ret; \
469         const size_t __recsize = sizeof(*__tmp->rectype); \
470         struct __kfifo *__kfifo = &__tmp->kfifo; \
471         if (__recsize) \
472                 __ret = __kfifo_out_peek_r(__kfifo, __val, sizeof(*__val), \
473                         __recsize); \
474         else { \
475                 __ret = !kfifo_is_empty(__tmp); \
476                 if (__ret) { \
477                         *(typeof(__tmp->type))__val = \
478                                 (__is_kfifo_ptr(__tmp) ? \
479                                 ((typeof(__tmp->type))__kfifo->data) : \
480                                 (__tmp->buf) \
481                                 )[__kfifo->out & __tmp->kfifo.mask]; \
482                         smp_wmb(); \
483                 } \
484         } \
485         __ret; \
486 }) \
487 )
488 
489 /**
490  * kfifo_in - put data into the fifo
491  * @fifo: address of the fifo to be used
492  * @buf: the data to be added
493  * @n: number of elements to be added
494  *
495  * This macro copies the given buffer into the fifo and returns the
496  * number of copied elements.
497  *
498  * Note that with only one concurrent reader and one concurrent
499  * writer, you don't need extra locking to use these macro.
500  */
501 #define kfifo_in(fifo, buf, n) \
502 ({ \
503         typeof((fifo) + 1) __tmp = (fifo); \
504         typeof(__tmp->ptr_const) __buf = (buf); \
505         unsigned long __n = (n); \
506         const size_t __recsize = sizeof(*__tmp->rectype); \
507         struct __kfifo *__kfifo = &__tmp->kfifo; \
508         (__recsize) ?\
509         __kfifo_in_r(__kfifo, __buf, __n, __recsize) : \
510         __kfifo_in(__kfifo, __buf, __n); \
511 })
512 
513 /**
514  * kfifo_in_spinlocked - put data into the fifo using a spinlock for locking
515  * @fifo: address of the fifo to be used
516  * @buf: the data to be added
517  * @n: number of elements to be added
518  * @lock: pointer to the spinlock to use for locking
519  *
520  * This macro copies the given values buffer into the fifo and returns the
521  * number of copied elements.
522  */
523 #define kfifo_in_spinlocked(fifo, buf, n, lock) \
524 ({ \
525         unsigned long __flags; \
526         unsigned int __ret; \
527         spin_lock_irqsave(lock, __flags); \
528         __ret = kfifo_in(fifo, buf, n); \
529         spin_unlock_irqrestore(lock, __flags); \
530         __ret; \
531 })
532 
533 /* alias for kfifo_in_spinlocked, will be removed in a future release */
534 #define kfifo_in_locked(fifo, buf, n, lock) \
535                 kfifo_in_spinlocked(fifo, buf, n, lock)
536 
537 /**
538  * kfifo_out - get data from the fifo
539  * @fifo: address of the fifo to be used
540  * @buf: pointer to the storage buffer
541  * @n: max. number of elements to get
542  *
543  * This macro get some data from the fifo and return the numbers of elements
544  * copied.
545  *
546  * Note that with only one concurrent reader and one concurrent
547  * writer, you don't need extra locking to use these macro.
548  */
549 #define kfifo_out(fifo, buf, n) \
550 __kfifo_uint_must_check_helper( \
551 ({ \
552         typeof((fifo) + 1) __tmp = (fifo); \
553         typeof(__tmp->ptr) __buf = (buf); \
554         unsigned long __n = (n); \
555         const size_t __recsize = sizeof(*__tmp->rectype); \
556         struct __kfifo *__kfifo = &__tmp->kfifo; \
557         (__recsize) ?\
558         __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \
559         __kfifo_out(__kfifo, __buf, __n); \
560 }) \
561 )
562 
563 /**
564  * kfifo_out_spinlocked - get data from the fifo using a spinlock for locking
565  * @fifo: address of the fifo to be used
566  * @buf: pointer to the storage buffer
567  * @n: max. number of elements to get
568  * @lock: pointer to the spinlock to use for locking
569  *
570  * This macro get the data from the fifo and return the numbers of elements
571  * copied.
572  */
573 #define kfifo_out_spinlocked(fifo, buf, n, lock) \
574 __kfifo_uint_must_check_helper( \
575 ({ \
576         unsigned long __flags; \
577         unsigned int __ret; \
578         spin_lock_irqsave(lock, __flags); \
579         __ret = kfifo_out(fifo, buf, n); \
580         spin_unlock_irqrestore(lock, __flags); \
581         __ret; \
582 }) \
583 )
584 
585 /* alias for kfifo_out_spinlocked, will be removed in a future release */
586 #define kfifo_out_locked(fifo, buf, n, lock) \
587                 kfifo_out_spinlocked(fifo, buf, n, lock)
588 
589 /**
590  * kfifo_from_user - puts some data from user space into the fifo
591  * @fifo: address of the fifo to be used
592  * @from: pointer to the data to be added
593  * @len: the length of the data to be added
594  * @copied: pointer to output variable to store the number of copied bytes
595  *
596  * This macro copies at most @len bytes from the @from into the
597  * fifo, depending of the available space and returns -EFAULT/0.
598  *
599  * Note that with only one concurrent reader and one concurrent
600  * writer, you don't need extra locking to use these macro.
601  */
602 #define kfifo_from_user(fifo, from, len, copied) \
603 __kfifo_uint_must_check_helper( \
604 ({ \
605         typeof((fifo) + 1) __tmp = (fifo); \
606         const void __user *__from = (from); \
607         unsigned int __len = (len); \
608         unsigned int *__copied = (copied); \
609         const size_t __recsize = sizeof(*__tmp->rectype); \
610         struct __kfifo *__kfifo = &__tmp->kfifo; \
611         (__recsize) ? \
612         __kfifo_from_user_r(__kfifo, __from, __len,  __copied, __recsize) : \
613         __kfifo_from_user(__kfifo, __from, __len, __copied); \
614 }) \
615 )
616 
617 /**
618  * kfifo_to_user - copies data from the fifo into user space
619  * @fifo: address of the fifo to be used
620  * @to: where the data must be copied
621  * @len: the size of the destination buffer
622  * @copied: pointer to output variable to store the number of copied bytes
623  *
624  * This macro copies at most @len bytes from the fifo into the
625  * @to buffer and returns -EFAULT/0.
626  *
627  * Note that with only one concurrent reader and one concurrent
628  * writer, you don't need extra locking to use these macro.
629  */
630 #define kfifo_to_user(fifo, to, len, copied) \
631 __kfifo_uint_must_check_helper( \
632 ({ \
633         typeof((fifo) + 1) __tmp = (fifo); \
634         void __user *__to = (to); \
635         unsigned int __len = (len); \
636         unsigned int *__copied = (copied); \
637         const size_t __recsize = sizeof(*__tmp->rectype); \
638         struct __kfifo *__kfifo = &__tmp->kfifo; \
639         (__recsize) ? \
640         __kfifo_to_user_r(__kfifo, __to, __len, __copied, __recsize) : \
641         __kfifo_to_user(__kfifo, __to, __len, __copied); \
642 }) \
643 )
644 
645 /**
646  * kfifo_dma_in_prepare - setup a scatterlist for DMA input
647  * @fifo: address of the fifo to be used
648  * @sgl: pointer to the scatterlist array
649  * @nents: number of entries in the scatterlist array
650  * @len: number of elements to transfer
651  *
652  * This macro fills a scatterlist for DMA input.
653  * It returns the number entries in the scatterlist array.
654  *
655  * Note that with only one concurrent reader and one concurrent
656  * writer, you don't need extra locking to use these macros.
657  */
658 #define kfifo_dma_in_prepare(fifo, sgl, nents, len) \
659 ({ \
660         typeof((fifo) + 1) __tmp = (fifo); \
661         struct scatterlist *__sgl = (sgl); \
662         int __nents = (nents); \
663         unsigned int __len = (len); \
664         const size_t __recsize = sizeof(*__tmp->rectype); \
665         struct __kfifo *__kfifo = &__tmp->kfifo; \
666         (__recsize) ? \
667         __kfifo_dma_in_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \
668         __kfifo_dma_in_prepare(__kfifo, __sgl, __nents, __len); \
669 })
670 
671 /**
672  * kfifo_dma_in_finish - finish a DMA IN operation
673  * @fifo: address of the fifo to be used
674  * @len: number of bytes to received
675  *
676  * This macro finish a DMA IN operation. The in counter will be updated by
677  * the len parameter. No error checking will be done.
678  *
679  * Note that with only one concurrent reader and one concurrent
680  * writer, you don't need extra locking to use these macros.
681  */
682 #define kfifo_dma_in_finish(fifo, len) \
683 (void)({ \
684         typeof((fifo) + 1) __tmp = (fifo); \
685         unsigned int __len = (len); \
686         const size_t __recsize = sizeof(*__tmp->rectype); \
687         struct __kfifo *__kfifo = &__tmp->kfifo; \
688         if (__recsize) \
689                 __kfifo_dma_in_finish_r(__kfifo, __len, __recsize); \
690         else \
691                 __kfifo->in += __len / sizeof(*__tmp->type); \
692 })
693 
694 /**
695  * kfifo_dma_out_prepare - setup a scatterlist for DMA output
696  * @fifo: address of the fifo to be used
697  * @sgl: pointer to the scatterlist array
698  * @nents: number of entries in the scatterlist array
699  * @len: number of elements to transfer
700  *
701  * This macro fills a scatterlist for DMA output which at most @len bytes
702  * to transfer.
703  * It returns the number entries in the scatterlist array.
704  * A zero means there is no space available and the scatterlist is not filled.
705  *
706  * Note that with only one concurrent reader and one concurrent
707  * writer, you don't need extra locking to use these macros.
708  */
709 #define kfifo_dma_out_prepare(fifo, sgl, nents, len) \
710 ({ \
711         typeof((fifo) + 1) __tmp = (fifo);  \
712         struct scatterlist *__sgl = (sgl); \
713         int __nents = (nents); \
714         unsigned int __len = (len); \
715         const size_t __recsize = sizeof(*__tmp->rectype); \
716         struct __kfifo *__kfifo = &__tmp->kfifo; \
717         (__recsize) ? \
718         __kfifo_dma_out_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \
719         __kfifo_dma_out_prepare(__kfifo, __sgl, __nents, __len); \
720 })
721 
722 /**
723  * kfifo_dma_out_finish - finish a DMA OUT operation
724  * @fifo: address of the fifo to be used
725  * @len: number of bytes transferred
726  *
727  * This macro finish a DMA OUT operation. The out counter will be updated by
728  * the len parameter. No error checking will be done.
729  *
730  * Note that with only one concurrent reader and one concurrent
731  * writer, you don't need extra locking to use these macros.
732  */
733 #define kfifo_dma_out_finish(fifo, len) \
734 (void)({ \
735         typeof((fifo) + 1) __tmp = (fifo); \
736         unsigned int __len = (len); \
737         const size_t __recsize = sizeof(*__tmp->rectype); \
738         struct __kfifo *__kfifo = &__tmp->kfifo; \
739         if (__recsize) \
740                 __kfifo_dma_out_finish_r(__kfifo, __recsize); \
741         else \
742                 __kfifo->out += __len / sizeof(*__tmp->type); \
743 })
744 
745 /**
746  * kfifo_out_peek - gets some data from the fifo
747  * @fifo: address of the fifo to be used
748  * @buf: pointer to the storage buffer
749  * @n: max. number of elements to get
750  *
751  * This macro get the data from the fifo and return the numbers of elements
752  * copied. The data is not removed from the fifo.
753  *
754  * Note that with only one concurrent reader and one concurrent
755  * writer, you don't need extra locking to use these macro.
756  */
757 #define kfifo_out_peek(fifo, buf, n) \
758 __kfifo_uint_must_check_helper( \
759 ({ \
760         typeof((fifo) + 1) __tmp = (fifo); \
761         typeof(__tmp->ptr) __buf = (buf); \
762         unsigned long __n = (n); \
763         const size_t __recsize = sizeof(*__tmp->rectype); \
764         struct __kfifo *__kfifo = &__tmp->kfifo; \
765         (__recsize) ? \
766         __kfifo_out_peek_r(__kfifo, __buf, __n, __recsize) : \
767         __kfifo_out_peek(__kfifo, __buf, __n); \
768 }) \
769 )
770 
771 extern int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
772         size_t esize, gfp_t gfp_mask);
773 
774 extern void __kfifo_free(struct __kfifo *fifo);
775 
776 extern int __kfifo_init(struct __kfifo *fifo, void *buffer,
777         unsigned int size, size_t esize);
778 
779 extern unsigned int __kfifo_in(struct __kfifo *fifo,
780         const void *buf, unsigned int len);
781 
782 extern unsigned int __kfifo_out(struct __kfifo *fifo,
783         void *buf, unsigned int len);
784 
785 extern int __kfifo_from_user(struct __kfifo *fifo,
786         const void __user *from, unsigned long len, unsigned int *copied);
787 
788 extern int __kfifo_to_user(struct __kfifo *fifo,
789         void __user *to, unsigned long len, unsigned int *copied);
790 
791 extern unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
792         struct scatterlist *sgl, int nents, unsigned int len);
793 
794 extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
795         struct scatterlist *sgl, int nents, unsigned int len);
796 
797 extern unsigned int __kfifo_out_peek(struct __kfifo *fifo,
798         void *buf, unsigned int len);
799 
800 extern unsigned int __kfifo_in_r(struct __kfifo *fifo,
801         const void *buf, unsigned int len, size_t recsize);
802 
803 extern unsigned int __kfifo_out_r(struct __kfifo *fifo,
804         void *buf, unsigned int len, size_t recsize);
805 
806 extern int __kfifo_from_user_r(struct __kfifo *fifo,
807         const void __user *from, unsigned long len, unsigned int *copied,
808         size_t recsize);
809 
810 extern int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
811         unsigned long len, unsigned int *copied, size_t recsize);
812 
813 extern unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
814         struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);
815 
816 extern void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
817         unsigned int len, size_t recsize);
818 
819 extern unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
820         struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);
821 
822 extern void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize);
823 
824 extern unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize);
825 
826 extern void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize);
827 
828 extern unsigned int __kfifo_out_peek_r(struct __kfifo *fifo,
829         void *buf, unsigned int len, size_t recsize);
830 
831 extern unsigned int __kfifo_max_r(unsigned int len, size_t recsize);
832 
833 #endif
834 

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