/* * A generic kernel FIFO implementation * * Copyright (C) 2013 Stefani Seibold <stefani@seibold.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * */ #ifndef _LINUX_KFIFO_H #define _LINUX_KFIFO_H /* * How to porting drivers to the new generic FIFO API: * * - Modify the declaration of the "struct kfifo *" object into a * in-place "struct kfifo" object * - Init the in-place object with kfifo_alloc() or kfifo_init() * Note: The address of the in-place "struct kfifo" object must be * passed as the first argument to this functions * - Replace the use of __kfifo_put into kfifo_in and __kfifo_get * into kfifo_out * - Replace the use of kfifo_put into kfifo_in_spinlocked and kfifo_get * into kfifo_out_spinlocked * Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc * must be passed now to the kfifo_in_spinlocked and kfifo_out_spinlocked * as the last parameter * - The formerly __kfifo_* functions are renamed into kfifo_* */ /* * Note about locking: There is no locking required until only one reader * and one writer is using the fifo and no kfifo_reset() will be called. * kfifo_reset_out() can be safely used, until it will be only called * in the reader thread. * For multiple writer and one reader there is only a need to lock the writer. * And vice versa for only one writer and multiple reader there is only a need * to lock the reader. */ #include <linux/kernel.h> #include <linux/spinlock.h> #include <linux/stddef.h> #include <linux/scatterlist.h> struct __kfifo { unsigned int in; unsigned int out; unsigned int mask; unsigned int esize; void *data; }; #define __STRUCT_KFIFO_COMMON(datatype, recsize, ptrtype) \ union { \ struct __kfifo kfifo; \ datatype *type; \ const datatype *const_type; \ char (*rectype)[recsize]; \ ptrtype *ptr; \ ptrtype const *ptr_const; \ } #define __STRUCT_KFIFO(type, size, recsize, ptrtype) \ { \ __STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \ type buf[((size < 2) || (size & (size - 1))) ? -1 : size]; \ } #define STRUCT_KFIFO(type, size) \ struct __STRUCT_KFIFO(type, size, 0, type) #define __STRUCT_KFIFO_PTR(type, recsize, ptrtype) \ { \ __STRUCT_KFIFO_COMMON(type, recsize, ptrtype); \ type buf[0]; \ } #define STRUCT_KFIFO_PTR(type) \ struct __STRUCT_KFIFO_PTR(type, 0, type) /* * define compatibility "struct kfifo" for dynamic allocated fifos */ struct kfifo __STRUCT_KFIFO_PTR(unsigned char, 0, void); #define STRUCT_KFIFO_REC_1(size) \ struct __STRUCT_KFIFO(unsigned char, size, 1, void) #define STRUCT_KFIFO_REC_2(size) \ struct __STRUCT_KFIFO(unsigned char, size, 2, void) /* * define kfifo_rec types */ struct kfifo_rec_ptr_1 __STRUCT_KFIFO_PTR(unsigned char, 1, void); struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR(unsigned char, 2, void); /* * helper macro to distinguish between real in place fifo where the fifo * array is a part of the structure and the fifo type where the array is * outside of the fifo structure. */ #define __is_kfifo_ptr(fifo) \ (sizeof(*fifo) == sizeof(STRUCT_KFIFO_PTR(typeof(*(fifo)->type)))) /** * DECLARE_KFIFO_PTR - macro to declare a fifo pointer object * @fifo: name of the declared fifo * @type: type of the fifo elements */ #define DECLARE_KFIFO_PTR(fifo, type) STRUCT_KFIFO_PTR(type) fifo /** * DECLARE_KFIFO - macro to declare a fifo object * @fifo: name of the declared fifo * @type: type of the fifo elements * @size: the number of elements in the fifo, this must be a power of 2 */ #define DECLARE_KFIFO(fifo, type, size) STRUCT_KFIFO(type, size) fifo /** * INIT_KFIFO - Initialize a fifo declared by DECLARE_KFIFO * @fifo: name of the declared fifo datatype */ #define INIT_KFIFO(fifo) \ (void)({ \ typeof(&(fifo)) __tmp = &(fifo); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ __kfifo->in = 0; \ __kfifo->out = 0; \ __kfifo->mask = __is_kfifo_ptr(__tmp) ? 0 : ARRAY_SIZE(__tmp->buf) - 1;\ __kfifo->esize = sizeof(*__tmp->buf); \ __kfifo->data = __is_kfifo_ptr(__tmp) ? NULL : __tmp->buf; \ }) /** * DEFINE_KFIFO - macro to define and initialize a fifo * @fifo: name of the declared fifo datatype * @type: type of the fifo elements * @size: the number of elements in the fifo, this must be a power of 2 * * Note: the macro can be used for global and local fifo data type variables. */ #define DEFINE_KFIFO(fifo, type, size) \ DECLARE_KFIFO(fifo, type, size) = \ (typeof(fifo)) { \ { \ { \ .in = 0, \ .out = 0, \ .mask = __is_kfifo_ptr(&(fifo)) ? \ 0 : \ ARRAY_SIZE((fifo).buf) - 1, \ .esize = sizeof(*(fifo).buf), \ .data = __is_kfifo_ptr(&(fifo)) ? \ NULL : \ (fifo).buf, \ } \ } \ } static inline unsigned int __must_check __kfifo_uint_must_check_helper(unsigned int val) { return val; } static inline int __must_check __kfifo_int_must_check_helper(int val) { return val; } /** * kfifo_initialized - Check if the fifo is initialized * @fifo: address of the fifo to check * * Return %true if fifo is initialized, otherwise %false. * Assumes the fifo was 0 before. */ #define kfifo_initialized(fifo) ((fifo)->kfifo.mask) /** * kfifo_esize - returns the size of the element managed by the fifo * @fifo: address of the fifo to be used */ #define kfifo_esize(fifo) ((fifo)->kfifo.esize) /** * kfifo_recsize - returns the size of the record length field * @fifo: address of the fifo to be used */ #define kfifo_recsize(fifo) (sizeof(*(fifo)->rectype)) /** * kfifo_size - returns the size of the fifo in elements * @fifo: address of the fifo to be used */ #define kfifo_size(fifo) ((fifo)->kfifo.mask + 1) /** * kfifo_reset - removes the entire fifo content * @fifo: address of the fifo to be used * * Note: usage of kfifo_reset() is dangerous. It should be only called when the * fifo is exclusived locked or when it is secured that no other thread is * accessing the fifo. */ #define kfifo_reset(fifo) \ (void)({ \ typeof((fifo) + 1) __tmp = (fifo); \ __tmp->kfifo.in = __tmp->kfifo.out = 0; \ }) /** * kfifo_reset_out - skip fifo content * @fifo: address of the fifo to be used * * Note: The usage of kfifo_reset_out() is safe until it will be only called * from the reader thread and there is only one concurrent reader. Otherwise * it is dangerous and must be handled in the same way as kfifo_reset(). */ #define kfifo_reset_out(fifo) \ (void)({ \ typeof((fifo) + 1) __tmp = (fifo); \ __tmp->kfifo.out = __tmp->kfifo.in; \ }) /** * kfifo_len - returns the number of used elements in the fifo * @fifo: address of the fifo to be used */ #define kfifo_len(fifo) \ ({ \ typeof((fifo) + 1) __tmpl = (fifo); \ __tmpl->kfifo.in - __tmpl->kfifo.out; \ }) /** * kfifo_is_empty - returns true if the fifo is empty * @fifo: address of the fifo to be used */ #define kfifo_is_empty(fifo) \ ({ \ typeof((fifo) + 1) __tmpq = (fifo); \ __tmpq->kfifo.in == __tmpq->kfifo.out; \ }) /** * kfifo_is_full - returns true if the fifo is full * @fifo: address of the fifo to be used */ #define kfifo_is_full(fifo) \ ({ \ typeof((fifo) + 1) __tmpq = (fifo); \ kfifo_len(__tmpq) > __tmpq->kfifo.mask; \ }) /** * kfifo_avail - returns the number of unused elements in the fifo * @fifo: address of the fifo to be used */ #define kfifo_avail(fifo) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmpq = (fifo); \ const size_t __recsize = sizeof(*__tmpq->rectype); \ unsigned int __avail = kfifo_size(__tmpq) - kfifo_len(__tmpq); \ (__recsize) ? ((__avail <= __recsize) ? 0 : \ __kfifo_max_r(__avail - __recsize, __recsize)) : \ __avail; \ }) \ ) /** * kfifo_skip - skip output data * @fifo: address of the fifo to be used */ #define kfifo_skip(fifo) \ (void)({ \ typeof((fifo) + 1) __tmp = (fifo); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ if (__recsize) \ __kfifo_skip_r(__kfifo, __recsize); \ else \ __kfifo->out++; \ }) /** * kfifo_peek_len - gets the size of the next fifo record * @fifo: address of the fifo to be used * * This function returns the size of the next fifo record in number of bytes. */ #define kfifo_peek_len(fifo) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (!__recsize) ? kfifo_len(__tmp) * sizeof(*__tmp->type) : \ __kfifo_len_r(__kfifo, __recsize); \ }) \ ) /** * kfifo_alloc - dynamically allocates a new fifo buffer * @fifo: pointer to the fifo * @size: the number of elements in the fifo, this must be a power of 2 * @gfp_mask: get_free_pages mask, passed to kmalloc() * * This macro dynamically allocates a new fifo buffer. * * The number of elements will be rounded-up to a power of 2. * The fifo will be release with kfifo_free(). * Return 0 if no error, otherwise an error code. */ #define kfifo_alloc(fifo, size, gfp_mask) \ __kfifo_int_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ __is_kfifo_ptr(__tmp) ? \ __kfifo_alloc(__kfifo, size, sizeof(*__tmp->type), gfp_mask) : \ -EINVAL; \ }) \ ) /** * kfifo_free - frees the fifo * @fifo: the fifo to be freed */ #define kfifo_free(fifo) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ if (__is_kfifo_ptr(__tmp)) \ __kfifo_free(__kfifo); \ }) /** * kfifo_init - initialize a fifo using a preallocated buffer * @fifo: the fifo to assign the buffer * @buffer: the preallocated buffer to be used * @size: the size of the internal buffer, this have to be a power of 2 * * This macro initializes a fifo using a preallocated buffer. * * The number of elements will be rounded-up to a power of 2. * Return 0 if no error, otherwise an error code. */ #define kfifo_init(fifo, buffer, size) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ __is_kfifo_ptr(__tmp) ? \ __kfifo_init(__kfifo, buffer, size, sizeof(*__tmp->type)) : \ -EINVAL; \ }) /** * kfifo_put - put data into the fifo * @fifo: address of the fifo to be used * @val: the data to be added * * This macro copies the given value into the fifo. * It returns 0 if the fifo was full. Otherwise it returns the number * processed elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_put(fifo, val) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ typeof(*__tmp->const_type) __val = (val); \ unsigned int __ret; \ size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ if (__recsize) \ __ret = __kfifo_in_r(__kfifo, &__val, sizeof(__val), \ __recsize); \ else { \ __ret = !kfifo_is_full(__tmp); \ if (__ret) { \ (__is_kfifo_ptr(__tmp) ? \ ((typeof(__tmp->type))__kfifo->data) : \ (__tmp->buf) \ )[__kfifo->in & __tmp->kfifo.mask] = \ *(typeof(__tmp->type))&__val; \ smp_wmb(); \ __kfifo->in++; \ } \ } \ __ret; \ }) /** * kfifo_get - get data from the fifo * @fifo: address of the fifo to be used * @val: address where to store the data * * This macro reads the data from the fifo. * It returns 0 if the fifo was empty. Otherwise it returns the number * processed elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_get(fifo, val) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ typeof(__tmp->ptr) __val = (val); \ unsigned int __ret; \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ if (__recsize) \ __ret = __kfifo_out_r(__kfifo, __val, sizeof(*__val), \ __recsize); \ else { \ __ret = !kfifo_is_empty(__tmp); \ if (__ret) { \ *(typeof(__tmp->type))__val = \ (__is_kfifo_ptr(__tmp) ? \ ((typeof(__tmp->type))__kfifo->data) : \ (__tmp->buf) \ )[__kfifo->out & __tmp->kfifo.mask]; \ smp_wmb(); \ __kfifo->out++; \ } \ } \ __ret; \ }) \ ) /** * kfifo_peek - get data from the fifo without removing * @fifo: address of the fifo to be used * @val: address where to store the data * * This reads the data from the fifo without removing it from the fifo. * It returns 0 if the fifo was empty. Otherwise it returns the number * processed elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_peek(fifo, val) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ typeof(__tmp->ptr) __val = (val); \ unsigned int __ret; \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ if (__recsize) \ __ret = __kfifo_out_peek_r(__kfifo, __val, sizeof(*__val), \ __recsize); \ else { \ __ret = !kfifo_is_empty(__tmp); \ if (__ret) { \ *(typeof(__tmp->type))__val = \ (__is_kfifo_ptr(__tmp) ? \ ((typeof(__tmp->type))__kfifo->data) : \ (__tmp->buf) \ )[__kfifo->out & __tmp->kfifo.mask]; \ smp_wmb(); \ } \ } \ __ret; \ }) \ ) /** * kfifo_in - put data into the fifo * @fifo: address of the fifo to be used * @buf: the data to be added * @n: number of elements to be added * * This macro copies the given buffer into the fifo and returns the * number of copied elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_in(fifo, buf, n) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ typeof(__tmp->ptr_const) __buf = (buf); \ unsigned long __n = (n); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (__recsize) ?\ __kfifo_in_r(__kfifo, __buf, __n, __recsize) : \ __kfifo_in(__kfifo, __buf, __n); \ }) /** * kfifo_in_spinlocked - put data into the fifo using a spinlock for locking * @fifo: address of the fifo to be used * @buf: the data to be added * @n: number of elements to be added * @lock: pointer to the spinlock to use for locking * * This macro copies the given values buffer into the fifo and returns the * number of copied elements. */ #define kfifo_in_spinlocked(fifo, buf, n, lock) \ ({ \ unsigned long __flags; \ unsigned int __ret; \ spin_lock_irqsave(lock, __flags); \ __ret = kfifo_in(fifo, buf, n); \ spin_unlock_irqrestore(lock, __flags); \ __ret; \ }) /* alias for kfifo_in_spinlocked, will be removed in a future release */ #define kfifo_in_locked(fifo, buf, n, lock) \ kfifo_in_spinlocked(fifo, buf, n, lock) /** * kfifo_out - get data from the fifo * @fifo: address of the fifo to be used * @buf: pointer to the storage buffer * @n: max. number of elements to get * * This macro get some data from the fifo and return the numbers of elements * copied. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_out(fifo, buf, n) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ typeof(__tmp->ptr) __buf = (buf); \ unsigned long __n = (n); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (__recsize) ?\ __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \ __kfifo_out(__kfifo, __buf, __n); \ }) \ ) /** * kfifo_out_spinlocked - get data from the fifo using a spinlock for locking * @fifo: address of the fifo to be used * @buf: pointer to the storage buffer * @n: max. number of elements to get * @lock: pointer to the spinlock to use for locking * * This macro get the data from the fifo and return the numbers of elements * copied. */ #define kfifo_out_spinlocked(fifo, buf, n, lock) \ __kfifo_uint_must_check_helper( \ ({ \ unsigned long __flags; \ unsigned int __ret; \ spin_lock_irqsave(lock, __flags); \ __ret = kfifo_out(fifo, buf, n); \ spin_unlock_irqrestore(lock, __flags); \ __ret; \ }) \ ) /* alias for kfifo_out_spinlocked, will be removed in a future release */ #define kfifo_out_locked(fifo, buf, n, lock) \ kfifo_out_spinlocked(fifo, buf, n, lock) /** * kfifo_from_user - puts some data from user space into the fifo * @fifo: address of the fifo to be used * @from: pointer to the data to be added * @len: the length of the data to be added * @copied: pointer to output variable to store the number of copied bytes * * This macro copies at most @len bytes from the @from into the * fifo, depending of the available space and returns -EFAULT/0. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_from_user(fifo, from, len, copied) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ const void __user *__from = (from); \ unsigned int __len = (len); \ unsigned int *__copied = (copied); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (__recsize) ? \ __kfifo_from_user_r(__kfifo, __from, __len, __copied, __recsize) : \ __kfifo_from_user(__kfifo, __from, __len, __copied); \ }) \ ) /** * kfifo_to_user - copies data from the fifo into user space * @fifo: address of the fifo to be used * @to: where the data must be copied * @len: the size of the destination buffer * @copied: pointer to output variable to store the number of copied bytes * * This macro copies at most @len bytes from the fifo into the * @to buffer and returns -EFAULT/0. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_to_user(fifo, to, len, copied) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ void __user *__to = (to); \ unsigned int __len = (len); \ unsigned int *__copied = (copied); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (__recsize) ? \ __kfifo_to_user_r(__kfifo, __to, __len, __copied, __recsize) : \ __kfifo_to_user(__kfifo, __to, __len, __copied); \ }) \ ) /** * kfifo_dma_in_prepare - setup a scatterlist for DMA input * @fifo: address of the fifo to be used * @sgl: pointer to the scatterlist array * @nents: number of entries in the scatterlist array * @len: number of elements to transfer * * This macro fills a scatterlist for DMA input. * It returns the number entries in the scatterlist array. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_in_prepare(fifo, sgl, nents, len) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ struct scatterlist *__sgl = (sgl); \ int __nents = (nents); \ unsigned int __len = (len); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (__recsize) ? \ __kfifo_dma_in_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \ __kfifo_dma_in_prepare(__kfifo, __sgl, __nents, __len); \ }) /** * kfifo_dma_in_finish - finish a DMA IN operation * @fifo: address of the fifo to be used * @len: number of bytes to received * * This macro finish a DMA IN operation. The in counter will be updated by * the len parameter. No error checking will be done. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_in_finish(fifo, len) \ (void)({ \ typeof((fifo) + 1) __tmp = (fifo); \ unsigned int __len = (len); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ if (__recsize) \ __kfifo_dma_in_finish_r(__kfifo, __len, __recsize); \ else \ __kfifo->in += __len / sizeof(*__tmp->type); \ }) /** * kfifo_dma_out_prepare - setup a scatterlist for DMA output * @fifo: address of the fifo to be used * @sgl: pointer to the scatterlist array * @nents: number of entries in the scatterlist array * @len: number of elements to transfer * * This macro fills a scatterlist for DMA output which at most @len bytes * to transfer. * It returns the number entries in the scatterlist array. * A zero means there is no space available and the scatterlist is not filled. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_out_prepare(fifo, sgl, nents, len) \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ struct scatterlist *__sgl = (sgl); \ int __nents = (nents); \ unsigned int __len = (len); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (__recsize) ? \ __kfifo_dma_out_prepare_r(__kfifo, __sgl, __nents, __len, __recsize) : \ __kfifo_dma_out_prepare(__kfifo, __sgl, __nents, __len); \ }) /** * kfifo_dma_out_finish - finish a DMA OUT operation * @fifo: address of the fifo to be used * @len: number of bytes transferred * * This macro finish a DMA OUT operation. The out counter will be updated by * the len parameter. No error checking will be done. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_out_finish(fifo, len) \ (void)({ \ typeof((fifo) + 1) __tmp = (fifo); \ unsigned int __len = (len); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ if (__recsize) \ __kfifo_dma_out_finish_r(__kfifo, __recsize); \ else \ __kfifo->out += __len / sizeof(*__tmp->type); \ }) /** * kfifo_out_peek - gets some data from the fifo * @fifo: address of the fifo to be used * @buf: pointer to the storage buffer * @n: max. number of elements to get * * This macro get the data from the fifo and return the numbers of elements * copied. The data is not removed from the fifo. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_out_peek(fifo, buf, n) \ __kfifo_uint_must_check_helper( \ ({ \ typeof((fifo) + 1) __tmp = (fifo); \ typeof(__tmp->ptr) __buf = (buf); \ unsigned long __n = (n); \ const size_t __recsize = sizeof(*__tmp->rectype); \ struct __kfifo *__kfifo = &__tmp->kfifo; \ (__recsize) ? \ __kfifo_out_peek_r(__kfifo, __buf, __n, __recsize) : \ __kfifo_out_peek(__kfifo, __buf, __n); \ }) \ ) extern int __kfifo_alloc(struct __kfifo *fifo, unsigned int size, size_t esize, gfp_t gfp_mask); extern void __kfifo_free(struct __kfifo *fifo); extern int __kfifo_init(struct __kfifo *fifo, void *buffer, unsigned int size, size_t esize); extern unsigned int __kfifo_in(struct __kfifo *fifo, const void *buf, unsigned int len); extern unsigned int __kfifo_out(struct __kfifo *fifo, void *buf, unsigned int len); extern int __kfifo_from_user(struct __kfifo *fifo, const void __user *from, unsigned long len, unsigned int *copied); extern int __kfifo_to_user(struct __kfifo *fifo, void __user *to, unsigned long len, unsigned int *copied); extern unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len); extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len); extern unsigned int __kfifo_out_peek(struct __kfifo *fifo, void *buf, unsigned int len); extern unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf, unsigned int len, size_t recsize); extern unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf, unsigned int len, size_t recsize); extern int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from, unsigned long len, unsigned int *copied, size_t recsize); extern int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to, unsigned long len, unsigned int *copied, size_t recsize); extern unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len, size_t recsize); extern void __kfifo_dma_in_finish_r(struct __kfifo *fifo, unsigned int len, size_t recsize); extern unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len, size_t recsize); extern void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize); extern unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize); extern void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize); extern unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf, unsigned int len, size_t recsize); extern unsigned int __kfifo_max_r(unsigned int len, size_t recsize); #endif