kfifo.h

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * A generic kernel FIFO implementation
   4 *
   5 * Copyright (C) 2013 Stefani Seibold <stefani@seibold.net>
   6 */
   7
   8#ifndef _LINUX_KFIFO_H
   9#define _LINUX_KFIFO_H
  10
  11/*
  12 * How to porting drivers to the new generic FIFO API:
  13 *
  14 * - Modify the declaration of the "struct kfifo *" object into a
  15 *   in-place "struct kfifo" object
  16 * - Init the in-place object with kfifo_alloc() or kfifo_init()
  17 *   Note: The address of the in-place "struct kfifo" object must be
  18 *   passed as the first argument to this functions
  19 * - Replace the use of __kfifo_put into kfifo_in and __kfifo_get
  20 *   into kfifo_out
  21 * - Replace the use of kfifo_put into kfifo_in_spinlocked and kfifo_get
  22 *   into kfifo_out_spinlocked
  23 *   Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc
  24 *   must be passed now to the kfifo_in_spinlocked and kfifo_out_spinlocked
  25 *   as the last parameter
  26 * - The formerly __kfifo_* functions are renamed into kfifo_*
  27 */
  28
  29/*
  30 * Note about locking: There is no locking required until only one reader
  31 * and one writer is using the fifo and no kfifo_reset() will be called.
  32 * kfifo_reset_out() can be safely used, until it will be only called
  33 * in the reader thread.
  34 * For multiple writer and one reader there is only a need to lock the writer.
  35 * And vice versa for only one writer and multiple reader there is only a need
  36 * to lock the reader.
  37 */
  38
  39#include <linux/array_size.h>
  40#include <linux/spinlock.h>
  41#include <linux/stddef.h>
  42#include <linux/types.h>
  43
  44#include <asm/barrier.h>
  45#include <asm/errno.h>
  46
  47struct scatterlist;
  48
  49struct __kfifo {
  50	unsigned int	in;
  51	unsigned int	out;
  52	unsigned int	mask;
  53	unsigned int	esize;
  54	void		*data;
  55};
  56
  57#define __STRUCT_KFIFO_COMMON(datatype, recsize, ptrtype) \
  58	union { \
  59		struct __kfifo	kfifo; \
  60		datatype	*type; \
  61		const datatype	*const_type; \
  62		char		(*rectype)[recsize]; \
  63		ptrtype		*ptr; \
  64		ptrtype const	*ptr_const; \
  65	}
  66
  67#define __STRUCT_KFIFO(type, size, recsize, ptrtype) \
  68{ \
  69	__STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
  70	type		buf[((size < 2) || (size & (size - 1))) ? -1 : size]; \
  71}
  72
  73#define STRUCT_KFIFO(type, size) \
  74	struct __STRUCT_KFIFO(type, size, 0, type)
  75
  76#define __STRUCT_KFIFO_PTR(type, recsize, ptrtype) \
  77{ \
  78	__STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \
  79	type		buf[0]; \
  80}
  81
  82#define STRUCT_KFIFO_PTR(type) \
  83	struct __STRUCT_KFIFO_PTR(type, 0, type)
  84
  85/*
  86 * define compatibility "struct kfifo" for dynamic allocated fifos
  87 */
  88struct kfifo __STRUCT_KFIFO_PTR(unsigned char, 0, void);
  89
  90#define STRUCT_KFIFO_REC_1(size) \
  91	struct __STRUCT_KFIFO(unsigned char, size, 1, void)
  92
  93#define STRUCT_KFIFO_REC_2(size) \
  94	struct __STRUCT_KFIFO(unsigned char, size, 2, void)
  95
  96/*
  97 * define kfifo_rec types
  98 */
  99struct kfifo_rec_ptr_1 __STRUCT_KFIFO_PTR(unsigned char, 1, void);
 100struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR(unsigned char, 2, void);
 101
 102/*
 103 * helper macro to distinguish between real in place fifo where the fifo
 104 * array is a part of the structure and the fifo type where the array is
 105 * outside of the fifo structure.
 106 */
 107#define	__is_kfifo_ptr(fifo) \
 108	(sizeof(*fifo) == sizeof(STRUCT_KFIFO_PTR(typeof(*(fifo)->type))))
 109
 110/**
 111 * DECLARE_KFIFO_PTR - macro to declare a fifo pointer object
 112 * @fifo: name of the declared fifo
 113 * @type: type of the fifo elements
 114 */
 115#define DECLARE_KFIFO_PTR(fifo, type)	STRUCT_KFIFO_PTR(type) fifo
 116
 117/**
 118 * DECLARE_KFIFO - macro to declare a fifo object
 119 * @fifo: name of the declared fifo
 120 * @type: type of the fifo elements
 121 * @size: the number of elements in the fifo, this must be a power of 2
 122 */
 123#define DECLARE_KFIFO(fifo, type, size)	STRUCT_KFIFO(type, size) fifo
 124
 125/**
 126 * INIT_KFIFO - Initialize a fifo declared by DECLARE_KFIFO
 127 * @fifo: name of the declared fifo datatype
 128 */
 129#define INIT_KFIFO(fifo) \
 130(void)({ \
 131	typeof(&(fifo)) __tmp = &(fifo); \
 132	struct __kfifo *__kfifo = &__tmp->kfifo; \
 133	__kfifo->in = 0; \
 134	__kfifo->out = 0; \
 135	__kfifo->mask = __is_kfifo_ptr(__tmp) ? 0 : ARRAY_SIZE(__tmp->buf) - 1;\
 136	__kfifo->esize = sizeof(*__tmp->buf); \
 137	__kfifo->data = __is_kfifo_ptr(__tmp) ?  NULL : __tmp->buf; \
 138})
 139
 140/**
 141 * DEFINE_KFIFO - macro to define and initialize a fifo
 142 * @fifo: name of the declared fifo datatype
 143 * @type: type of the fifo elements
 144 * @size: the number of elements in the fifo, this must be a power of 2
 145 *
 146 * Note: the macro can be used for global and local fifo data type variables.
 147 */
 148#define DEFINE_KFIFO(fifo, type, size) \
 149	DECLARE_KFIFO(fifo, type, size) = \
 150	(typeof(fifo)) { \
 151		{ \
 152			{ \
 153			.in	= 0, \
 154			.out	= 0, \
 155			.mask	= __is_kfifo_ptr(&(fifo)) ? \
 156				  0 : \
 157				  ARRAY_SIZE((fifo).buf) - 1, \
 158			.esize	= sizeof(*(fifo).buf), \
 159			.data	= __is_kfifo_ptr(&(fifo)) ? \
 160				NULL : \
 161				(fifo).buf, \
 162			} \
 163		} \
 164	}
 165
 166
 167static inline unsigned int __must_check
 168__kfifo_uint_must_check_helper(unsigned int val)
 169{
 170	return val;
 171}
 172
 173static inline int __must_check
 174__kfifo_int_must_check_helper(int val)
 175{
 176	return val;
 177}
 178
 179/**
 180 * kfifo_initialized - Check if the fifo is initialized
 181 * @fifo: address of the fifo to check
 182 *
 183 * Return %true if fifo is initialized, otherwise %false.
 184 * Assumes the fifo was 0 before.
 185 */
 186#define kfifo_initialized(fifo) ((fifo)->kfifo.mask)
 187
 188/**
 189 * kfifo_esize - returns the size of the element managed by the fifo
 190 * @fifo: address of the fifo to be used
 191 */
 192#define kfifo_esize(fifo)	((fifo)->kfifo.esize)
 193
 194/**
 195 * kfifo_recsize - returns the size of the record length field
 196 * @fifo: address of the fifo to be used
 197 */
 198#define kfifo_recsize(fifo)	(sizeof(*(fifo)->rectype))
 199
 200/**
 201 * kfifo_size - returns the size of the fifo in elements
 202 * @fifo: address of the fifo to be used
 203 */
 204#define kfifo_size(fifo)	((fifo)->kfifo.mask + 1)
 205
 206/**
 207 * kfifo_reset - removes the entire fifo content
 208 * @fifo: address of the fifo to be used
 209 *
 210 * Note: usage of kfifo_reset() is dangerous. It should be only called when the
 211 * fifo is exclusived locked or when it is secured that no other thread is
 212 * accessing the fifo.
 213 */
 214#define kfifo_reset(fifo) \
 215(void)({ \
 216	typeof((fifo) + 1) __tmp = (fifo); \
 217	__tmp->kfifo.in = __tmp->kfifo.out = 0; \
 218})
 219
 220/**
 221 * kfifo_reset_out - skip fifo content
 222 * @fifo: address of the fifo to be used
 223 *
 224 * Note: The usage of kfifo_reset_out() is safe until it will be only called
 225 * from the reader thread and there is only one concurrent reader. Otherwise
 226 * it is dangerous and must be handled in the same way as kfifo_reset().
 227 */
 228#define kfifo_reset_out(fifo)	\
 229(void)({ \
 230	typeof((fifo) + 1) __tmp = (fifo); \
 231	__tmp->kfifo.out = __tmp->kfifo.in; \
 232})
 233
 234/**
 235 * kfifo_len - returns the number of used elements in the fifo
 236 * @fifo: address of the fifo to be used
 237 */
 238#define kfifo_len(fifo) \
 239({ \
 240	typeof((fifo) + 1) __tmpl = (fifo); \
 241	__tmpl->kfifo.in - __tmpl->kfifo.out; \
 242})
 243
 244/**
 245 * kfifo_is_empty - returns true if the fifo is empty
 246 * @fifo: address of the fifo to be used
 247 */
 248#define	kfifo_is_empty(fifo) \
 249({ \
 250	typeof((fifo) + 1) __tmpq = (fifo); \
 251	__tmpq->kfifo.in == __tmpq->kfifo.out; \
 252})
 253
 254/**
 255 * kfifo_is_empty_spinlocked - returns true if the fifo is empty using
 256 * a spinlock for locking
 257 * @fifo: address of the fifo to be used
 258 * @lock: spinlock to be used for locking
 259 */
 260#define kfifo_is_empty_spinlocked(fifo, lock) \
 261({ \
 262	unsigned long __flags; \
 263	bool __ret; \
 264	spin_lock_irqsave(lock, __flags); \
 265	__ret = kfifo_is_empty(fifo); \
 266	spin_unlock_irqrestore(lock, __flags); \
 267	__ret; \
 268})
 269
 270/**
 271 * kfifo_is_empty_spinlocked_noirqsave  - returns true if the fifo is empty
 272 * using a spinlock for locking, doesn't disable interrupts
 273 * @fifo: address of the fifo to be used
 274 * @lock: spinlock to be used for locking
 275 */
 276#define kfifo_is_empty_spinlocked_noirqsave(fifo, lock) \
 277({ \
 278	bool __ret; \
 279	spin_lock(lock); \
 280	__ret = kfifo_is_empty(fifo); \
 281	spin_unlock(lock); \
 282	__ret; \
 283})
 284
 285/**
 286 * kfifo_is_full - returns true if the fifo is full
 287 * @fifo: address of the fifo to be used
 288 */
 289#define	kfifo_is_full(fifo) \
 290({ \
 291	typeof((fifo) + 1) __tmpq = (fifo); \
 292	kfifo_len(__tmpq) > __tmpq->kfifo.mask; \
 293})
 294
 295/**
 296 * kfifo_avail - returns the number of unused elements in the fifo
 297 * @fifo: address of the fifo to be used
 298 */
 299#define	kfifo_avail(fifo) \
 300__kfifo_uint_must_check_helper( \
 301({ \
 302	typeof((fifo) + 1) __tmpq = (fifo); \
 303	const size_t __recsize = sizeof(*__tmpq->rectype); \
 304	unsigned int __avail = kfifo_size(__tmpq) - kfifo_len(__tmpq); \
 305	(__recsize) ? ((__avail <= __recsize) ? 0 : \
 306	__kfifo_max_r(__avail - __recsize, __recsize)) : \
 307	__avail; \
 308}) \
 309)
 310
 311/**
 312 * kfifo_skip_count - skip output data
 313 * @fifo: address of the fifo to be used
 314 * @count: count of data to skip
 315 */
 316#define	kfifo_skip_count(fifo, count) do { \
 317	typeof((fifo) + 1) __tmp = (fifo); \
 318	const size_t __recsize = sizeof(*__tmp->rectype); \
 319	struct __kfifo *__kfifo = &__tmp->kfifo; \
 320	if (__recsize) \
 321		__kfifo_skip_r(__kfifo, __recsize); \
 322	else \
 323		__kfifo->out += (count); \
 324} while(0)
 325
 326/**
 327 * kfifo_skip - skip output data
 328 * @fifo: address of the fifo to be used
 329 */
 330#define	kfifo_skip(fifo)	kfifo_skip_count(fifo, 1)
 331
 332/**
 333 * kfifo_peek_len - gets the size of the next fifo record
 334 * @fifo: address of the fifo to be used
 335 *
 336 * This function returns the size of the next fifo record in number of bytes.
 337 */
 338#define kfifo_peek_len(fifo) \
 339__kfifo_uint_must_check_helper( \
 340({ \
 341	typeof((fifo) + 1) __tmp = (fifo); \
 342	const size_t __recsize = sizeof(*__tmp->rectype); \
 343	struct __kfifo *__kfifo = &__tmp->kfifo; \
 344	(!__recsize) ? kfifo_len(__tmp) * sizeof(*__tmp->type) : \
 345	__kfifo_len_r(__kfifo, __recsize); \
 346}) \
 347)
 348
 349/**
 350 * kfifo_alloc - dynamically allocates a new fifo buffer
 351 * @fifo: pointer to the fifo
 352 * @size: the number of elements in the fifo, this must be a power of 2
 353 * @gfp_mask: get_free_pages mask, passed to kmalloc()
 354 *
 355 * This macro dynamically allocates a new fifo buffer.
 356 *
 357 * The number of elements will be rounded-up to a power of 2.
 358 * The fifo will be release with kfifo_free().
 359 * Return 0 if no error, otherwise an error code.
 360 */
 361#define kfifo_alloc(fifo, size, gfp_mask) \
 362__kfifo_int_must_check_helper( \
 363({ \
 364	typeof((fifo) + 1) __tmp = (fifo); \
 365	struct __kfifo *__kfifo = &__tmp->kfifo; \
 366	__is_kfifo_ptr(__tmp) ? \
 367	__kfifo_alloc(__kfifo, size, sizeof(*__tmp->type), gfp_mask) : \
 368	-EINVAL; \
 369}) \
 370)
 371
 372/**
 373 * kfifo_alloc_node - dynamically allocates a new fifo buffer on a NUMA node
 374 * @fifo: pointer to the fifo
 375 * @size: the number of elements in the fifo, this must be a power of 2
 376 * @gfp_mask: get_free_pages mask, passed to kmalloc()
 377 * @node: NUMA node to allocate memory on
 378 *
 379 * This macro dynamically allocates a new fifo buffer with NUMA node awareness.
 380 *
 381 * The number of elements will be rounded-up to a power of 2.
 382 * The fifo will be release with kfifo_free().
 383 * Return 0 if no error, otherwise an error code.
 384 */
 385#define kfifo_alloc_node(fifo, size, gfp_mask, node) \
 386__kfifo_int_must_check_helper( \
 387({ \
 388	typeof((fifo) + 1) __tmp = (fifo); \
 389	struct __kfifo *__kfifo = &__tmp->kfifo; \
 390	__is_kfifo_ptr(__tmp) ? \
 391	__kfifo_alloc_node(__kfifo, size, sizeof(*__tmp->type), gfp_mask, node) : \
 392	-EINVAL; \
 393}) \
 394)
 395
 396/**
 397 * kfifo_free - frees the fifo
 398 * @fifo: the fifo to be freed
 399 */
 400#define kfifo_free(fifo) \
 401({ \
 402	typeof((fifo) + 1) __tmp = (fifo); \
 403	struct __kfifo *__kfifo = &__tmp->kfifo; \
 404	if (__is_kfifo_ptr(__tmp)) \
 405		__kfifo_free(__kfifo); \
 406})
 407
 408/**
 409 * kfifo_init - initialize a fifo using a preallocated buffer
 410 * @fifo: the fifo to assign the buffer
 411 * @buffer: the preallocated buffer to be used
 412 * @size: the size of the internal buffer, this have to be a power of 2
 413 *
 414 * This macro initializes a fifo using a preallocated buffer.
 415 *
 416 * The number of elements will be rounded-up to a power of 2.
 417 * Return 0 if no error, otherwise an error code.
 418 */
 419#define kfifo_init(fifo, buffer, size) \
 420({ \
 421	typeof((fifo) + 1) __tmp = (fifo); \
 422	struct __kfifo *__kfifo = &__tmp->kfifo; \
 423	__is_kfifo_ptr(__tmp) ? \
 424	__kfifo_init(__kfifo, buffer, size, sizeof(*__tmp->type)) : \
 425	-EINVAL; \
 426})
 427
 428/**
 429 * kfifo_put - put data into the fifo
 430 * @fifo: address of the fifo to be used
 431 * @val: the data to be added
 432 *
 433 * This macro copies the given value into the fifo.
 434 * It returns 0 if the fifo was full. Otherwise it returns the number
 435 * processed elements.
 436 *
 437 * Note that with only one concurrent reader and one concurrent
 438 * writer, you don't need extra locking to use these macro.
 439 */
 440#define	kfifo_put(fifo, val) \
 441({ \
 442	typeof((fifo) + 1) __tmp = (fifo); \
 443	typeof(*__tmp->const_type) __val = (val); \
 444	unsigned int __ret; \
 445	size_t __recsize = sizeof(*__tmp->rectype); \
 446	struct __kfifo *__kfifo = &__tmp->kfifo; \
 447	if (__recsize) \
 448		__ret = __kfifo_in_r(__kfifo, &__val, sizeof(__val), \
 449			__recsize); \
 450	else { \
 451		__ret = !kfifo_is_full(__tmp); \
 452		if (__ret) { \
 453			(__is_kfifo_ptr(__tmp) ? \
 454			((typeof(__tmp->type))__kfifo->data) : \
 455			(__tmp->buf) \
 456			)[__kfifo->in & __tmp->kfifo.mask] = \
 457				*(typeof(__tmp->type))&__val; \
 458			smp_wmb(); \
 459			__kfifo->in++; \
 460		} \
 461	} \
 462	__ret; \
 463})
 464
 465/**
 466 * kfifo_get - get data from the fifo
 467 * @fifo: address of the fifo to be used
 468 * @val: address where to store the data
 469 *
 470 * This macro reads the data from the fifo.
 471 * It returns 0 if the fifo was empty. Otherwise it returns the number
 472 * processed elements.
 473 *
 474 * Note that with only one concurrent reader and one concurrent
 475 * writer, you don't need extra locking to use these macro.
 476 */
 477#define	kfifo_get(fifo, val) \
 478__kfifo_uint_must_check_helper( \
 479({ \
 480	typeof((fifo) + 1) __tmp = (fifo); \
 481	typeof(__tmp->ptr) __val = (val); \
 482	unsigned int __ret; \
 483	const size_t __recsize = sizeof(*__tmp->rectype); \
 484	struct __kfifo *__kfifo = &__tmp->kfifo; \
 485	if (__recsize) \
 486		__ret = __kfifo_out_r(__kfifo, __val, sizeof(*__val), \
 487			__recsize); \
 488	else { \
 489		__ret = !kfifo_is_empty(__tmp); \
 490		if (__ret) { \
 491			*(typeof(__tmp->type))__val = \
 492				(__is_kfifo_ptr(__tmp) ? \
 493				((typeof(__tmp->type))__kfifo->data) : \
 494				(__tmp->buf) \
 495				)[__kfifo->out & __tmp->kfifo.mask]; \
 496			smp_wmb(); \
 497			__kfifo->out++; \
 498		} \
 499	} \
 500	__ret; \
 501}) \
 502)
 503
 504/**
 505 * kfifo_peek - get data from the fifo without removing
 506 * @fifo: address of the fifo to be used
 507 * @val: address where to store the data
 508 *
 509 * This reads the data from the fifo without removing it from the fifo.
 510 * It returns 0 if the fifo was empty. Otherwise it returns the number
 511 * processed elements.
 512 *
 513 * Note that with only one concurrent reader and one concurrent
 514 * writer, you don't need extra locking to use these macro.
 515 */
 516#define	kfifo_peek(fifo, val) \
 517__kfifo_uint_must_check_helper( \
 518({ \
 519	typeof((fifo) + 1) __tmp = (fifo); \
 520	typeof(__tmp->ptr) __val = (val); \
 521	unsigned int __ret; \
 522	const size_t __recsize = sizeof(*__tmp->rectype); \
 523	struct __kfifo *__kfifo = &__tmp->kfifo; \
 524	if (__recsize) \
 525		__ret = __kfifo_out_peek_r(__kfifo, __val, sizeof(*__val), \
 526			__recsize); \
 527	else { \
 528		__ret = !kfifo_is_empty(__tmp); \
 529		if (__ret) { \
 530			*(typeof(__tmp->type))__val = \
 531				(__is_kfifo_ptr(__tmp) ? \
 532				((typeof(__tmp->type))__kfifo->data) : \
 533				(__tmp->buf) \
 534				)[__kfifo->out & __tmp->kfifo.mask]; \
 535			smp_wmb(); \
 536		} \
 537	} \
 538	__ret; \
 539}) \
 540)
 541
 542/**
 543 * kfifo_in - put data into the fifo
 544 * @fifo: address of the fifo to be used
 545 * @buf: the data to be added
 546 * @n: number of elements to be added
 547 *
 548 * This macro copies the given buffer into the fifo and returns the
 549 * number of copied elements.
 550 *
 551 * Note that with only one concurrent reader and one concurrent
 552 * writer, you don't need extra locking to use these macro.
 553 */
 554#define	kfifo_in(fifo, buf, n) \
 555({ \
 556	typeof((fifo) + 1) __tmp = (fifo); \
 557	typeof(__tmp->ptr_const) __buf = (buf); \
 558	unsigned long __n = (n); \
 559	const size_t __recsize = sizeof(*__tmp->rectype); \
 560	struct __kfifo *__kfifo = &__tmp->kfifo; \
 561	(__recsize) ?\
 562	__kfifo_in_r(__kfifo, __buf, __n, __recsize) : \
 563	__kfifo_in(__kfifo, __buf, __n); \
 564})
 565
 566/**
 567 * kfifo_in_spinlocked - put data into the fifo using a spinlock for locking
 568 * @fifo: address of the fifo to be used
 569 * @buf: the data to be added
 570 * @n: number of elements to be added
 571 * @lock: pointer to the spinlock to use for locking
 572 *
 573 * This macro copies the given values buffer into the fifo and returns the
 574 * number of copied elements.
 575 */
 576#define	kfifo_in_spinlocked(fifo, buf, n, lock) \
 577({ \
 578	unsigned long __flags; \
 579	unsigned int __ret; \
 580	spin_lock_irqsave(lock, __flags); \
 581	__ret = kfifo_in(fifo, buf, n); \
 582	spin_unlock_irqrestore(lock, __flags); \
 583	__ret; \
 584})
 585
 586/**
 587 * kfifo_in_spinlocked_noirqsave - put data into fifo using a spinlock for
 588 * locking, don't disable interrupts
 589 * @fifo: address of the fifo to be used
 590 * @buf: the data to be added
 591 * @n: number of elements to be added
 592 * @lock: pointer to the spinlock to use for locking
 593 *
 594 * This is a variant of kfifo_in_spinlocked() but uses spin_lock/unlock()
 595 * for locking and doesn't disable interrupts.
 596 */
 597#define kfifo_in_spinlocked_noirqsave(fifo, buf, n, lock) \
 598({ \
 599	unsigned int __ret; \
 600	spin_lock(lock); \
 601	__ret = kfifo_in(fifo, buf, n); \
 602	spin_unlock(lock); \
 603	__ret; \
 604})
 605
 606/* alias for kfifo_in_spinlocked, will be removed in a future release */
 607#define kfifo_in_locked(fifo, buf, n, lock) \
 608		kfifo_in_spinlocked(fifo, buf, n, lock)
 609
 610/**
 611 * kfifo_out - get data from the fifo
 612 * @fifo: address of the fifo to be used
 613 * @buf: pointer to the storage buffer
 614 * @n: max. number of elements to get
 615 *
 616 * This macro gets some data from the fifo and returns the numbers of elements
 617 * copied.
 618 *
 619 * Note that with only one concurrent reader and one concurrent
 620 * writer, you don't need extra locking to use these macro.
 621 */
 622#define	kfifo_out(fifo, buf, n) \
 623__kfifo_uint_must_check_helper( \
 624({ \
 625	typeof((fifo) + 1) __tmp = (fifo); \
 626	typeof(__tmp->ptr) __buf = (buf); \
 627	unsigned long __n = (n); \
 628	const size_t __recsize = sizeof(*__tmp->rectype); \
 629	struct __kfifo *__kfifo = &__tmp->kfifo; \
 630	(__recsize) ?\
 631	__kfifo_out_r(__kfifo, __buf, __n, __recsize) : \
 632	__kfifo_out(__kfifo, __buf, __n); \
 633}) \
 634)
 635
 636/**
 637 * kfifo_out_spinlocked - get data from the fifo using a spinlock for locking
 638 * @fifo: address of the fifo to be used
 639 * @buf: pointer to the storage buffer
 640 * @n: max. number of elements to get
 641 * @lock: pointer to the spinlock to use for locking
 642 *
 643 * This macro gets the data from the fifo and returns the numbers of elements
 644 * copied.
 645 */
 646#define	kfifo_out_spinlocked(fifo, buf, n, lock) \
 647__kfifo_uint_must_check_helper( \
 648({ \
 649	unsigned long __flags; \
 650	unsigned int __ret; \
 651	spin_lock_irqsave(lock, __flags); \
 652	__ret = kfifo_out(fifo, buf, n); \
 653	spin_unlock_irqrestore(lock, __flags); \
 654	__ret; \
 655}) \
 656)
 657
 658/**
 659 * kfifo_out_spinlocked_noirqsave - get data from the fifo using a spinlock
 660 * for locking, don't disable interrupts
 661 * @fifo: address of the fifo to be used
 662 * @buf: pointer to the storage buffer
 663 * @n: max. number of elements to get
 664 * @lock: pointer to the spinlock to use for locking
 665 *
 666 * This is a variant of kfifo_out_spinlocked() which uses spin_lock/unlock()
 667 * for locking and doesn't disable interrupts.
 668 */
 669#define kfifo_out_spinlocked_noirqsave(fifo, buf, n, lock) \
 670__kfifo_uint_must_check_helper( \
 671({ \
 672	unsigned int __ret; \
 673	spin_lock(lock); \
 674	__ret = kfifo_out(fifo, buf, n); \
 675	spin_unlock(lock); \
 676	__ret; \
 677}) \
 678)
 679
 680/* alias for kfifo_out_spinlocked, will be removed in a future release */
 681#define kfifo_out_locked(fifo, buf, n, lock) \
 682		kfifo_out_spinlocked(fifo, buf, n, lock)
 683
 684/**
 685 * kfifo_from_user - puts some data from user space into the fifo
 686 * @fifo: address of the fifo to be used
 687 * @from: pointer to the data to be added
 688 * @len: the length of the data to be added
 689 * @copied: pointer to output variable to store the number of copied bytes
 690 *
 691 * This macro copies at most @len bytes from the @from into the
 692 * fifo, depending of the available space and returns -EFAULT/0.
 693 *
 694 * Note that with only one concurrent reader and one concurrent
 695 * writer, you don't need extra locking to use these macro.
 696 */
 697#define	kfifo_from_user(fifo, from, len, copied) \
 698__kfifo_uint_must_check_helper( \
 699({ \
 700	typeof((fifo) + 1) __tmp = (fifo); \
 701	const void __user *__from = (from); \
 702	unsigned int __len = (len); \
 703	unsigned int *__copied = (copied); \
 704	const size_t __recsize = sizeof(*__tmp->rectype); \
 705	struct __kfifo *__kfifo = &__tmp->kfifo; \
 706	(__recsize) ? \
 707	__kfifo_from_user_r(__kfifo, __from, __len,  __copied, __recsize) : \
 708	__kfifo_from_user(__kfifo, __from, __len, __copied); \
 709}) \
 710)
 711
 712/**
 713 * kfifo_to_user - copies data from the fifo into user space
 714 * @fifo: address of the fifo to be used
 715 * @to: where the data must be copied
 716 * @len: the size of the destination buffer
 717 * @copied: pointer to output variable to store the number of copied bytes
 718 *
 719 * This macro copies at most @len bytes from the fifo into the
 720 * @to buffer and returns -EFAULT/0.
 721 *
 722 * Note that with only one concurrent reader and one concurrent
 723 * writer, you don't need extra locking to use these macro.
 724 */
 725#define	kfifo_to_user(fifo, to, len, copied) \
 726__kfifo_int_must_check_helper( \
 727({ \
 728	typeof((fifo) + 1) __tmp = (fifo); \
 729	void __user *__to = (to); \
 730	unsigned int __len = (len); \
 731	unsigned int *__copied = (copied); \
 732	const size_t __recsize = sizeof(*__tmp->rectype); \
 733	struct __kfifo *__kfifo = &__tmp->kfifo; \
 734	(__recsize) ? \
 735	__kfifo_to_user_r(__kfifo, __to, __len, __copied, __recsize) : \
 736	__kfifo_to_user(__kfifo, __to, __len, __copied); \
 737}) \
 738)
 739
 740/**
 741 * kfifo_dma_in_prepare_mapped - setup a scatterlist for DMA input
 742 * @fifo: address of the fifo to be used
 743 * @sgl: pointer to the scatterlist array
 744 * @nents: number of entries in the scatterlist array
 745 * @len: number of elements to transfer
 746 * @dma: mapped dma address to fill into @sgl
 747 *
 748 * This macro fills a scatterlist for DMA input.
 749 * It returns the number entries in the scatterlist array.
 750 *
 751 * Note that with only one concurrent reader and one concurrent
 752 * writer, you don't need extra locking to use these macros.
 753 */
 754#define	kfifo_dma_in_prepare_mapped(fifo, sgl, nents, len, dma) \
 755({ \
 756	typeof((fifo) + 1) __tmp = (fifo); \
 757	struct scatterlist *__sgl = (sgl); \
 758	int __nents = (nents); \
 759	unsigned int __len = (len); \
 760	const size_t __recsize = sizeof(*__tmp->rectype); \
 761	struct __kfifo *__kfifo = &__tmp->kfifo; \
 762	(__recsize) ? \
 763	__kfifo_dma_in_prepare_r(__kfifo, __sgl, __nents, __len, __recsize, \
 764				 dma) : \
 765	__kfifo_dma_in_prepare(__kfifo, __sgl, __nents, __len, dma); \
 766})
 767
 768#define kfifo_dma_in_prepare(fifo, sgl, nents, len) \
 769	kfifo_dma_in_prepare_mapped(fifo, sgl, nents, len, DMA_MAPPING_ERROR)
 770
 771/**
 772 * kfifo_dma_in_finish - finish a DMA IN operation
 773 * @fifo: address of the fifo to be used
 774 * @len: number of bytes to received
 775 *
 776 * This macro finishes a DMA IN operation. The in counter will be updated by
 777 * the len parameter. No error checking will be done.
 778 *
 779 * Note that with only one concurrent reader and one concurrent
 780 * writer, you don't need extra locking to use these macros.
 781 */
 782#define kfifo_dma_in_finish(fifo, len) \
 783(void)({ \
 784	typeof((fifo) + 1) __tmp = (fifo); \
 785	unsigned int __len = (len); \
 786	const size_t __recsize = sizeof(*__tmp->rectype); \
 787	struct __kfifo *__kfifo = &__tmp->kfifo; \
 788	if (__recsize) \
 789		__kfifo_dma_in_finish_r(__kfifo, __len, __recsize); \
 790	else \
 791		__kfifo->in += __len / sizeof(*__tmp->type); \
 792})
 793
 794/**
 795 * kfifo_dma_out_prepare_mapped - setup a scatterlist for DMA output
 796 * @fifo: address of the fifo to be used
 797 * @sgl: pointer to the scatterlist array
 798 * @nents: number of entries in the scatterlist array
 799 * @len: number of elements to transfer
 800 * @dma: mapped dma address to fill into @sgl
 801 *
 802 * This macro fills a scatterlist for DMA output which at most @len bytes
 803 * to transfer.
 804 * It returns the number entries in the scatterlist array.
 805 * A zero means there is no space available and the scatterlist is not filled.
 806 *
 807 * Note that with only one concurrent reader and one concurrent
 808 * writer, you don't need extra locking to use these macros.
 809 */
 810#define	kfifo_dma_out_prepare_mapped(fifo, sgl, nents, len, dma) \
 811({ \
 812	typeof((fifo) + 1) __tmp = (fifo);  \
 813	struct scatterlist *__sgl = (sgl); \
 814	int __nents = (nents); \
 815	unsigned int __len = (len); \
 816	const size_t __recsize = sizeof(*__tmp->rectype); \
 817	struct __kfifo *__kfifo = &__tmp->kfifo; \
 818	(__recsize) ? \
 819	__kfifo_dma_out_prepare_r(__kfifo, __sgl, __nents, __len, __recsize, \
 820				  dma) : \
 821	__kfifo_dma_out_prepare(__kfifo, __sgl, __nents, __len, dma); \
 822})
 823
 824#define	kfifo_dma_out_prepare(fifo, sgl, nents, len) \
 825	kfifo_dma_out_prepare_mapped(fifo, sgl, nents, len, DMA_MAPPING_ERROR)
 826
 827/**
 828 * kfifo_dma_out_finish - finish a DMA OUT operation
 829 * @fifo: address of the fifo to be used
 830 * @len: number of bytes transferred
 831 *
 832 * This macro finishes a DMA OUT operation. The out counter will be updated by
 833 * the len parameter. No error checking will be done.
 834 *
 835 * Note that with only one concurrent reader and one concurrent
 836 * writer, you don't need extra locking to use these macros.
 837 */
 838#define kfifo_dma_out_finish(fifo, len) do { \
 839	typeof((fifo) + 1) ___tmp = (fifo); \
 840	kfifo_skip_count(___tmp, (len) / sizeof(*___tmp->type)); \
 841} while (0)
 842
 843/**
 844 * kfifo_out_peek - gets some data from the fifo
 845 * @fifo: address of the fifo to be used
 846 * @buf: pointer to the storage buffer
 847 * @n: max. number of elements to get
 848 *
 849 * This macro gets the data from the fifo and returns the numbers of elements
 850 * copied. The data is not removed from the fifo.
 851 *
 852 * Note that with only one concurrent reader and one concurrent
 853 * writer, you don't need extra locking to use these macro.
 854 */
 855#define	kfifo_out_peek(fifo, buf, n) \
 856__kfifo_uint_must_check_helper( \
 857({ \
 858	typeof((fifo) + 1) __tmp = (fifo); \
 859	typeof(__tmp->ptr) __buf = (buf); \
 860	unsigned long __n = (n); \
 861	const size_t __recsize = sizeof(*__tmp->rectype); \
 862	struct __kfifo *__kfifo = &__tmp->kfifo; \
 863	(__recsize) ? \
 864	__kfifo_out_peek_r(__kfifo, __buf, __n, __recsize) : \
 865	__kfifo_out_peek(__kfifo, __buf, __n); \
 866}) \
 867)
 868
 869/**
 870 * kfifo_out_linear - gets a tail of/offset to available data
 871 * @fifo: address of the fifo to be used
 872 * @tail: pointer to an unsigned int to store the value of tail
 873 * @n: max. number of elements to point at
 874 *
 875 * This macro obtains the offset (tail) to the available data in the fifo
 876 * buffer and returns the
 877 * numbers of elements available. It returns the available count till the end
 878 * of data or till the end of the buffer. So that it can be used for linear
 879 * data processing (like memcpy() of (@fifo->data + @tail) with count
 880 * returned).
 881 *
 882 * Note that with only one concurrent reader and one concurrent
 883 * writer, you don't need extra locking to use these macro.
 884 */
 885#define kfifo_out_linear(fifo, tail, n) \
 886__kfifo_uint_must_check_helper( \
 887({ \
 888	typeof((fifo) + 1) __tmp = (fifo); \
 889	unsigned int *__tail = (tail); \
 890	unsigned long __n = (n); \
 891	const size_t __recsize = sizeof(*__tmp->rectype); \
 892	struct __kfifo *__kfifo = &__tmp->kfifo; \
 893	(__recsize) ? \
 894	__kfifo_out_linear_r(__kfifo, __tail, __n, __recsize) : \
 895	__kfifo_out_linear(__kfifo, __tail, __n); \
 896}) \
 897)
 898
 899/**
 900 * kfifo_out_linear_ptr - gets a pointer to the available data
 901 * @fifo: address of the fifo to be used
 902 * @ptr: pointer to data to store the pointer to tail
 903 * @n: max. number of elements to point at
 904 *
 905 * Similarly to kfifo_out_linear(), this macro obtains the pointer to the
 906 * available data in the fifo buffer and returns the numbers of elements
 907 * available. It returns the available count till the end of available data or
 908 * till the end of the buffer. So that it can be used for linear data
 909 * processing (like memcpy() of @ptr with count returned).
 910 *
 911 * Note that with only one concurrent reader and one concurrent
 912 * writer, you don't need extra locking to use these macro.
 913 */
 914#define kfifo_out_linear_ptr(fifo, ptr, n) \
 915__kfifo_uint_must_check_helper( \
 916({ \
 917	typeof((fifo) + 1) ___tmp = (fifo); \
 918	unsigned int ___tail; \
 919	unsigned int ___n = kfifo_out_linear(___tmp, &___tail, (n)); \
 920	*(ptr) = ___tmp->kfifo.data + ___tail * kfifo_esize(___tmp); \
 921	___n; \
 922}) \
 923)
 924
 925
 926extern int __kfifo_alloc_node(struct __kfifo *fifo, unsigned int size,
 927	size_t esize, gfp_t gfp_mask, int node);
 928
 929static inline int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
 930				size_t esize, gfp_t gfp_mask)
 931{
 932	return __kfifo_alloc_node(fifo, size, esize, gfp_mask, NUMA_NO_NODE);
 933}
 934
 935extern void __kfifo_free(struct __kfifo *fifo);
 936
 937extern int __kfifo_init(struct __kfifo *fifo, void *buffer,
 938	unsigned int size, size_t esize);
 939
 940extern unsigned int __kfifo_in(struct __kfifo *fifo,
 941	const void *buf, unsigned int len);
 942
 943extern unsigned int __kfifo_out(struct __kfifo *fifo,
 944	void *buf, unsigned int len);
 945
 946extern int __kfifo_from_user(struct __kfifo *fifo,
 947	const void __user *from, unsigned long len, unsigned int *copied);
 948
 949extern int __kfifo_to_user(struct __kfifo *fifo,
 950	void __user *to, unsigned long len, unsigned int *copied);
 951
 952extern unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
 953	struct scatterlist *sgl, int nents, unsigned int len, dma_addr_t dma);
 954
 955extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
 956	struct scatterlist *sgl, int nents, unsigned int len, dma_addr_t dma);
 957
 958extern unsigned int __kfifo_out_peek(struct __kfifo *fifo,
 959	void *buf, unsigned int len);
 960
 961extern unsigned int __kfifo_out_linear(struct __kfifo *fifo,
 962	unsigned int *tail, unsigned int n);
 963
 964extern unsigned int __kfifo_in_r(struct __kfifo *fifo,
 965	const void *buf, unsigned int len, size_t recsize);
 966
 967extern unsigned int __kfifo_out_r(struct __kfifo *fifo,
 968	void *buf, unsigned int len, size_t recsize);
 969
 970extern int __kfifo_from_user_r(struct __kfifo *fifo,
 971	const void __user *from, unsigned long len, unsigned int *copied,
 972	size_t recsize);
 973
 974extern int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
 975	unsigned long len, unsigned int *copied, size_t recsize);
 976
 977extern unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
 978	struct scatterlist *sgl, int nents, unsigned int len, size_t recsize,
 979	dma_addr_t dma);
 980
 981extern void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
 982	unsigned int len, size_t recsize);
 983
 984extern unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
 985	struct scatterlist *sgl, int nents, unsigned int len, size_t recsize,
 986	dma_addr_t dma);
 987
 988extern unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize);
 989
 990extern void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize);
 991
 992extern unsigned int __kfifo_out_peek_r(struct __kfifo *fifo,
 993	void *buf, unsigned int len, size_t recsize);
 994
 995extern unsigned int __kfifo_out_linear_r(struct __kfifo *fifo,
 996	unsigned int *tail, unsigned int n, size_t recsize);
 997
 998extern unsigned int __kfifo_max_r(unsigned int len, size_t recsize);
 999
1000#endif