linux/include/linux/kfifo.h
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   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
  58struct __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 */
  97struct 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 */
 108struct kfifo_rec_ptr_1 __STRUCT_KFIFO_PTR(unsigned char, 1, void);
 109struct 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
 175static inline unsigned int __must_check
 176__kfifo_uint_must_check_helper(unsigned int val)
 177{
 178        return val;
 179}
 180
 181static 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
 771extern int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
 772        size_t esize, gfp_t gfp_mask);
 773
 774extern void __kfifo_free(struct __kfifo *fifo);
 775
 776extern int __kfifo_init(struct __kfifo *fifo, void *buffer,
 777        unsigned int size, size_t esize);
 778
 779extern unsigned int __kfifo_in(struct __kfifo *fifo,
 780        const void *buf, unsigned int len);
 781
 782extern unsigned int __kfifo_out(struct __kfifo *fifo,
 783        void *buf, unsigned int len);
 784
 785extern int __kfifo_from_user(struct __kfifo *fifo,
 786        const void __user *from, unsigned long len, unsigned int *copied);
 787
 788extern int __kfifo_to_user(struct __kfifo *fifo,
 789        void __user *to, unsigned long len, unsigned int *copied);
 790
 791extern unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
 792        struct scatterlist *sgl, int nents, unsigned int len);
 793
 794extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
 795        struct scatterlist *sgl, int nents, unsigned int len);
 796
 797extern unsigned int __kfifo_out_peek(struct __kfifo *fifo,
 798        void *buf, unsigned int len);
 799
 800extern unsigned int __kfifo_in_r(struct __kfifo *fifo,
 801        const void *buf, unsigned int len, size_t recsize);
 802
 803extern unsigned int __kfifo_out_r(struct __kfifo *fifo,
 804        void *buf, unsigned int len, size_t recsize);
 805
 806extern int __kfifo_from_user_r(struct __kfifo *fifo,
 807        const void __user *from, unsigned long len, unsigned int *copied,
 808        size_t recsize);
 809
 810extern int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
 811        unsigned long len, unsigned int *copied, size_t recsize);
 812
 813extern unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
 814        struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);
 815
 816extern void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
 817        unsigned int len, size_t recsize);
 818
 819extern unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
 820        struct scatterlist *sgl, int nents, unsigned int len, size_t recsize);
 821
 822extern void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize);
 823
 824extern unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize);
 825
 826extern void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize);
 827
 828extern unsigned int __kfifo_out_peek_r(struct __kfifo *fifo,
 829        void *buf, unsigned int len, size_t recsize);
 830
 831extern unsigned int __kfifo_max_r(unsigned int len, size_t recsize);
 832
 833#endif
 834