clib/include/bkfifo.h

#ifndef _BKFIFO_H_
#define _BKFIFO_H_

struct _kfifo_ {
	unsigned int	in;
	unsigned int	out;
	unsigned int	mask;
	unsigned int	esize;
	void*			data;
};

#define _SRTUCT_KFIFO_COMMON_(datatype, recsize, ptrtype) \
	union { \
		struct _kfifo_ kfifo; \
	}

#define _SRTUCT_KFIFO_(type, size, recsize, ptrtype) \
{ \
	_STRUCT_KFIFO_COMMON_(type, recsize, ptrtype); \
	type		buf[((size < 2) || (size & (size - 1))) ? -1 : size]; \
}

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * A generic kernel FIFO implementation
 *
 * Copyright (C) 2013 Stefani Seibold <stefani@seibold.net>
 */

#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.
   */

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_empty_spinlocked - returns true if the fifo is empty using
		 * a spinlock for locking
		 * @fifo: address of the fifo to be used
		 * @lock: spinlock to be used for locking
		 */
#define kfifo_is_empty_spinlocked(fifo, lock) \
({ \
	unsigned long __flags; \
	bool __ret; \
	spin_lock_irqsave(lock, __flags); \
	__ret = kfifo_is_empty(fifo); \
	spin_unlock_irqrestore(lock, __flags); \
	__ret; \
})

		 /**
		  * kfifo_is_empty_spinlocked_noirqsave  - returns true if the fifo is empty
		  * using a spinlock for locking, doesn't disable interrupts
		  * @fifo: address of the fifo to be used
		  * @lock: spinlock to be used for locking
		  */
#define kfifo_is_empty_spinlocked_noirqsave(fifo, lock) \
({ \
	bool __ret; \
	spin_lock(lock); \
	__ret = kfifo_is_empty(fifo); \
	spin_unlock(lock); \
	__ret; \
})

		  /**
		   * 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; \
})

					  /**
					   * kfifo_in_spinlocked_noirqsave - put data into fifo using a spinlock for
					   * locking, don't disable interrupts
					   * @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 is a variant of kfifo_in_spinlocked() but uses spin_lock/unlock()
					   * for locking and doesn't disable interrupts.
					   */
#define kfifo_in_spinlocked_noirqsave(fifo, buf, n, lock) \
({ \
	unsigned int __ret; \
	spin_lock(lock); \
	__ret = kfifo_in(fifo, buf, n); \
	spin_unlock(lock); \
	__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; \
}) \
)

  /**
   * kfifo_out_spinlocked_noirqsave - get data from the fifo using a spinlock
   * for locking, don't disable interrupts
   * @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 is a variant of kfifo_out_spinlocked() which uses spin_lock/unlock()
   * for locking and doesn't disable interrupts.
   */
#define kfifo_out_spinlocked_noirqsave(fifo, buf, n, lock) \
__kfifo_uint_must_check_helper( \
({ \
	unsigned int __ret; \
	spin_lock(lock); \
	__ret = kfifo_out(fifo, buf, n); \
	spin_unlock(lock); \
	__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_int_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);

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * A generic kernel FIFO implementation
 *
 * Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
 */

//#include <linux/kernel.h>
//#include <linux/export.h>
//#include <linux/slab.h>
//#include <linux/err.h>
//#include <linux/log2.h>
//#include <linux/uaccess.h>
//#include <linux/kfifo.h>

// /*
//  * internal helper to calculate the unused elements in a fifo
//  */
//static inline unsigned int kfifo_unused(struct __kfifo* fifo)
//{
//	return (fifo->mask + 1) - (fifo->in - fifo->out);
//}
//
//int __kfifo_alloc(struct __kfifo* fifo, unsigned int size,
//	size_t esize, gfp_t gfp_mask)
//{
//	/*
//	 * round up to the next power of 2, since our 'let the indices
//	 * wrap' technique works only in this case.
//	 */
//	size = roundup_pow_of_two(size);
//
//	fifo->in = 0;
//	fifo->out = 0;
//	fifo->esize = esize;
//
//	if (size < 2) {
//		fifo->data = NULL;
//		fifo->mask = 0;
//		return -EINVAL;
//	}
//
//	fifo->data = kmalloc_array(esize, size, gfp_mask);
//
//	if (!fifo->data) {
//		fifo->mask = 0;
//		return -ENOMEM;
//	}
//	fifo->mask = size - 1;
//
//	return 0;
//}
//EXPORT_SYMBOL(__kfifo_alloc);
//
//void __kfifo_free(struct __kfifo* fifo)
//{
//	kfree(fifo->data);
//	fifo->in = 0;
//	fifo->out = 0;
//	fifo->esize = 0;
//	fifo->data = NULL;
//	fifo->mask = 0;
//}
//EXPORT_SYMBOL(__kfifo_free);
//
//int __kfifo_init(struct __kfifo* fifo, void* buffer,
//	unsigned int size, size_t esize)
//{
//	size /= esize;
//
//	if (!is_power_of_2(size))
//		size = rounddown_pow_of_two(size);
//
//	fifo->in = 0;
//	fifo->out = 0;
//	fifo->esize = esize;
//	fifo->data = buffer;
//
//	if (size < 2) {
//		fifo->mask = 0;
//		return -EINVAL;
//	}
//	fifo->mask = size - 1;
//
//	return 0;
//}
//EXPORT_SYMBOL(__kfifo_init);
//
//static void kfifo_copy_in(struct __kfifo* fifo, const void* src,
//	unsigned int len, unsigned int off)
//{
//	unsigned int size = fifo->mask + 1;
//	unsigned int esize = fifo->esize;
//	unsigned int l;
//
//	off &= fifo->mask;
//	if (esize != 1) {
//		off *= esize;
//		size *= esize;
//		len *= esize;
//	}
//	l = min(len, size - off);
//
//	memcpy(fifo->data + off, src, l);
//	memcpy(fifo->data, src + l, len - l);
//	/*
//	 * make sure that the data in the fifo is up to date before
//	 * incrementing the fifo->in index counter
//	 */
//	smp_wmb();
//}
//
//unsigned int __kfifo_in(struct __kfifo* fifo,
//	const void* buf, unsigned int len)
//{
//	unsigned int l;
//
//	l = kfifo_unused(fifo);
//	if (len > l)
//		len = l;
//
//	kfifo_copy_in(fifo, buf, len, fifo->in);
//	fifo->in += len;
//	return len;
//}
//EXPORT_SYMBOL(__kfifo_in);
//
//static void kfifo_copy_out(struct __kfifo* fifo, void* dst,
//	unsigned int len, unsigned int off)
//{
//	unsigned int size = fifo->mask + 1;
//	unsigned int esize = fifo->esize;
//	unsigned int l;
//
//	off &= fifo->mask;
//	if (esize != 1) {
//		off *= esize;
//		size *= esize;
//		len *= esize;
//	}
//	l = min(len, size - off);
//
//	memcpy(dst, fifo->data + off, l);
//	memcpy(dst + l, fifo->data, len - l);
//	/*
//	 * make sure that the data is copied before
//	 * incrementing the fifo->out index counter
//	 */
//	smp_wmb();
//}
//
//unsigned int __kfifo_out_peek(struct __kfifo* fifo,
//	void* buf, unsigned int len)
//{
//	unsigned int l;
//
//	l = fifo->in - fifo->out;
//	if (len > l)
//		len = l;
//
//	kfifo_copy_out(fifo, buf, len, fifo->out);
//	return len;
//}
//EXPORT_SYMBOL(__kfifo_out_peek);
//
//unsigned int __kfifo_out(struct __kfifo* fifo,
//	void* buf, unsigned int len)
//{
//	len = __kfifo_out_peek(fifo, buf, len);
//	fifo->out += len;
//	return len;
//}
//EXPORT_SYMBOL(__kfifo_out);
//
//static unsigned long kfifo_copy_from_user(struct __kfifo* fifo,
//	const void __user* from, unsigned int len, unsigned int off,
//	unsigned int* copied)
//{
//	unsigned int size = fifo->mask + 1;
//	unsigned int esize = fifo->esize;
//	unsigned int l;
//	unsigned long ret;
//
//	off &= fifo->mask;
//	if (esize != 1) {
//		off *= esize;
//		size *= esize;
//		len *= esize;
//	}
//	l = min(len, size - off);
//
//	ret = copy_from_user(fifo->data + off, from, l);
//	if (unlikely(ret))
//		ret = DIV_ROUND_UP(ret + len - l, esize);
//	else {
//		ret = copy_from_user(fifo->data, from + l, len - l);
//		if (unlikely(ret))
//			ret = DIV_ROUND_UP(ret, esize);
//	}
//	/*
//	 * make sure that the data in the fifo is up to date before
//	 * incrementing the fifo->in index counter
//	 */
//	smp_wmb();
//	*copied = len - ret * esize;
//	/* return the number of elements which are not copied */
//	return ret;
//}
//
//int __kfifo_from_user(struct __kfifo* fifo, const void __user* from,
//	unsigned long len, unsigned int* copied)
//{
//	unsigned int l;
//	unsigned long ret;
//	unsigned int esize = fifo->esize;
//	int err;
//
//	if (esize != 1)
//		len /= esize;
//
//	l = kfifo_unused(fifo);
//	if (len > l)
//		len = l;
//
//	ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied);
//	if (unlikely(ret)) {
//		len -= ret;
//		err = -EFAULT;
//	}
//	else
//		err = 0;
//	fifo->in += len;
//	return err;
//}
//EXPORT_SYMBOL(__kfifo_from_user);
//
//static unsigned long kfifo_copy_to_user(struct __kfifo* fifo, void __user* to,
//	unsigned int len, unsigned int off, unsigned int* copied)
//{
//	unsigned int l;
//	unsigned long ret;
//	unsigned int size = fifo->mask + 1;
//	unsigned int esize = fifo->esize;
//
//	off &= fifo->mask;
//	if (esize != 1) {
//		off *= esize;
//		size *= esize;
//		len *= esize;
//	}
//	l = min(len, size - off);
//
//	ret = copy_to_user(to, fifo->data + off, l);
//	if (unlikely(ret))
//		ret = DIV_ROUND_UP(ret + len - l, esize);
//	else {
//		ret = copy_to_user(to + l, fifo->data, len - l);
//		if (unlikely(ret))
//			ret = DIV_ROUND_UP(ret, esize);
//	}
//	/*
//	 * make sure that the data is copied before
//	 * incrementing the fifo->out index counter
//	 */
//	smp_wmb();
//	*copied = len - ret * esize;
//	/* return the number of elements which are not copied */
//	return ret;
//}
//
//int __kfifo_to_user(struct __kfifo* fifo, void __user* to,
//	unsigned long len, unsigned int* copied)
//{
//	unsigned int l;
//	unsigned long ret;
//	unsigned int esize = fifo->esize;
//	int err;
//
//	if (esize != 1)
//		len /= esize;
//
//	l = fifo->in - fifo->out;
//	if (len > l)
//		len = l;
//	ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied);
//	if (unlikely(ret)) {
//		len -= ret;
//		err = -EFAULT;
//	}
//	else
//		err = 0;
//	fifo->out += len;
//	return err;
//}
//EXPORT_SYMBOL(__kfifo_to_user);
//
//static int setup_sgl_buf(struct scatterlist* sgl, void* buf,
//	int nents, unsigned int len)
//{
//	int n;
//	unsigned int l;
//	unsigned int off;
//	struct page* page;
//
//	if (!nents)
//		return 0;
//
//	if (!len)
//		return 0;
//
//	n = 0;
//	page = virt_to_page(buf);
//	off = offset_in_page(buf);
//	l = 0;
//
//	while (len >= l + PAGE_SIZE - off) {
//		struct page* npage;
//
//		l += PAGE_SIZE;
//		buf += PAGE_SIZE;
//		npage = virt_to_page(buf);
//		if (page_to_phys(page) != page_to_phys(npage) - l) {
//			sg_set_page(sgl, page, l - off, off);
//			sgl = sg_next(sgl);
//			if (++n == nents || sgl == NULL)
//				return n;
//			page = npage;
//			len -= l - off;
//			l = off = 0;
//		}
//	}
//	sg_set_page(sgl, page, len, off);
//	return n + 1;
//}
//
//static unsigned int setup_sgl(struct __kfifo* fifo, struct scatterlist* sgl,
//	int nents, unsigned int len, unsigned int off)
//{
//	unsigned int size = fifo->mask + 1;
//	unsigned int esize = fifo->esize;
//	unsigned int l;
//	unsigned int n;
//
//	off &= fifo->mask;
//	if (esize != 1) {
//		off *= esize;
//		size *= esize;
//		len *= esize;
//	}
//	l = min(len, size - off);
//
//	n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
//	n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);
//
//	return n;
//}
//
//unsigned int __kfifo_dma_in_prepare(struct __kfifo* fifo,
//	struct scatterlist* sgl, int nents, unsigned int len)
//{
//	unsigned int l;
//
//	l = kfifo_unused(fifo);
//	if (len > l)
//		len = l;
//
//	return setup_sgl(fifo, sgl, nents, len, fifo->in);
//}
//EXPORT_SYMBOL(__kfifo_dma_in_prepare);
//
//unsigned int __kfifo_dma_out_prepare(struct __kfifo* fifo,
//	struct scatterlist* sgl, int nents, unsigned int len)
//{
//	unsigned int l;
//
//	l = fifo->in - fifo->out;
//	if (len > l)
//		len = l;
//
//	return setup_sgl(fifo, sgl, nents, len, fifo->out);
//}
//EXPORT_SYMBOL(__kfifo_dma_out_prepare);
//
//unsigned int __kfifo_max_r(unsigned int len, size_t recsize)
//{
//	unsigned int max = (1 << (recsize << 3)) - 1;
//
//	if (len > max)
//		return max;
//	return len;
//}
//EXPORT_SYMBOL(__kfifo_max_r);
//
//#define	__KFIFO_PEEK(data, out, mask) \
//	((data)[(out) & (mask)])
///*
// * __kfifo_peek_n internal helper function for determinate the length of
// * the next record in the fifo
// */
//static unsigned int __kfifo_peek_n(struct __kfifo* fifo, size_t recsize)
//{
//	unsigned int l;
//	unsigned int mask = fifo->mask;
//	unsigned char* data = fifo->data;
//
//	l = __KFIFO_PEEK(data, fifo->out, mask);
//
//	if (--recsize)
//		l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8;
//
//	return l;
//}
//
//#define	__KFIFO_POKE(data, in, mask, val) \
//	( \
//	(data)[(in) & (mask)] = (unsigned char)(val) \
//	)
//
///*
// * __kfifo_poke_n internal helper function for storing the length of
// * the record into the fifo
// */
//static void __kfifo_poke_n(struct __kfifo* fifo, unsigned int n, size_t recsize)
//{
//	unsigned int mask = fifo->mask;
//	unsigned char* data = fifo->data;
//
//	__KFIFO_POKE(data, fifo->in, mask, n);
//
//	if (recsize > 1)
//		__KFIFO_POKE(data, fifo->in + 1, mask, n >> 8);
//}
//
//unsigned int __kfifo_len_r(struct __kfifo* fifo, size_t recsize)
//{
//	return __kfifo_peek_n(fifo, recsize);
//}
//EXPORT_SYMBOL(__kfifo_len_r);
//
//unsigned int __kfifo_in_r(struct __kfifo* fifo, const void* buf,
//	unsigned int len, size_t recsize)
//{
//	if (len + recsize > kfifo_unused(fifo))
//		return 0;
//
//	__kfifo_poke_n(fifo, len, recsize);
//
//	kfifo_copy_in(fifo, buf, len, fifo->in + recsize);
//	fifo->in += len + recsize;
//	return len;
//}
//EXPORT_SYMBOL(__kfifo_in_r);
//
//static unsigned int kfifo_out_copy_r(struct __kfifo* fifo,
//	void* buf, unsigned int len, size_t recsize, unsigned int* n)
//{
//	*n = __kfifo_peek_n(fifo, recsize);
//
//	if (len > *n)
//		len = *n;
//
//	kfifo_copy_out(fifo, buf, len, fifo->out + recsize);
//	return len;
//}
//
//unsigned int __kfifo_out_peek_r(struct __kfifo* fifo, void* buf,
//	unsigned int len, size_t recsize)
//{
//	unsigned int n;
//
//	if (fifo->in == fifo->out)
//		return 0;
//
//	return kfifo_out_copy_r(fifo, buf, len, recsize, &n);
//}
//EXPORT_SYMBOL(__kfifo_out_peek_r);
//
//unsigned int __kfifo_out_r(struct __kfifo* fifo, void* buf,
//	unsigned int len, size_t recsize)
//{
//	unsigned int n;
//
//	if (fifo->in == fifo->out)
//		return 0;
//
//	len = kfifo_out_copy_r(fifo, buf, len, recsize, &n);
//	fifo->out += n + recsize;
//	return len;
//}
//EXPORT_SYMBOL(__kfifo_out_r);
//
//void __kfifo_skip_r(struct __kfifo* fifo, size_t recsize)
//{
//	unsigned int n;
//
//	n = __kfifo_peek_n(fifo, recsize);
//	fifo->out += n + recsize;
//}
//EXPORT_SYMBOL(__kfifo_skip_r);
//
//int __kfifo_from_user_r(struct __kfifo* fifo, const void __user* from,
//	unsigned long len, unsigned int* copied, size_t recsize)
//{
//	unsigned long ret;
//
//	len = __kfifo_max_r(len, recsize);
//
//	if (len + recsize > kfifo_unused(fifo)) {
//		*copied = 0;
//		return 0;
//	}
//
//	__kfifo_poke_n(fifo, len, recsize);
//
//	ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied);
//	if (unlikely(ret)) {
//		*copied = 0;
//		return -EFAULT;
//	}
//	fifo->in += len + recsize;
//	return 0;
//}
//EXPORT_SYMBOL(__kfifo_from_user_r);
//
//int __kfifo_to_user_r(struct __kfifo* fifo, void __user* to,
//	unsigned long len, unsigned int* copied, size_t recsize)
//{
//	unsigned long ret;
//	unsigned int n;
//
//	if (fifo->in == fifo->out) {
//		*copied = 0;
//		return 0;
//	}
//
//	n = __kfifo_peek_n(fifo, recsize);
//	if (len > n)
//		len = n;
//
//	ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied);
//	if (unlikely(ret)) {
//		*copied = 0;
//		return -EFAULT;
//	}
//	fifo->out += n + recsize;
//	return 0;
//}
//EXPORT_SYMBOL(__kfifo_to_user_r);
//
//unsigned int __kfifo_dma_in_prepare_r(struct __kfifo* fifo,
//	struct scatterlist* sgl, int nents, unsigned int len, size_t recsize)
//{
//	BUG_ON(!nents);
//
//	len = __kfifo_max_r(len, recsize);
//
//	if (len + recsize > kfifo_unused(fifo))
//		return 0;
//
//	return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);
//}
//EXPORT_SYMBOL(__kfifo_dma_in_prepare_r);
//
//void __kfifo_dma_in_finish_r(struct __kfifo* fifo,
//	unsigned int len, size_t recsize)
//{
//	len = __kfifo_max_r(len, recsize);
//	__kfifo_poke_n(fifo, len, recsize);
//	fifo->in += len + recsize;
//}
//EXPORT_SYMBOL(__kfifo_dma_in_finish_r);
//
//unsigned int __kfifo_dma_out_prepare_r(struct __kfifo* fifo,
//	struct scatterlist* sgl, int nents, unsigned int len, size_t recsize)
//{
//	BUG_ON(!nents);
//
//	len = __kfifo_max_r(len, recsize);
//
//	if (len + recsize > fifo->in - fifo->out)
//		return 0;
//
//	return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);
//}
//EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);
//
//void __kfifo_dma_out_finish_r(struct __kfifo* fifo, size_t recsize)
//{
//	unsigned int len;
//
//	len = __kfifo_peek_n(fifo, recsize);
//	fifo->out += len + recsize;
//}
//EXPORT_SYMBOL(__kfifo_dma_out_finish_r);


#endif


#endif // _BKFIFO_H_