/*
* A generic kernel FIFO implementation.
*
* Copyright (C) 2009 Stefani Seibold/Munich/Germany <stef...@seibold.net>
* Copyright (C) 2004 Stelian Pop <stel...@popies.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
#include <linux/kernel.h>
#define KFIFO_F_NOTRIM 1 /* do not cut of the record */
struct kfifo {
unsigned long size; /* the size of the allocated buffer */
unsigned long in; /* data is added at offset (in&(size-1)) */
unsigned long out; /* data is extracted from off. (out&(size-1)) */
unsigned char *buffer; /* the buffer holding the data */
};
#define KFIFO_INIT(s, b) \
(struct kfifo) { \
.size = s, \
.in = 0, \
.out = 0, \
.buffer = b \
}
#define DECLARE_KFIFO(name, size) \
union { \
struct kfifo name; \
unsigned char name##_buffer[size + sizeof(struct kfifo)]; \
}
#define DEFINE_KFIFO(name, size) \
DECLARE_KFIFO(name, size) = KFIFO_INIT(name, size)
#define INIT_KFIFO(name) \
name = KFIFO_INIT(sizeof(name##_buffer) - sizeof(struct kfifo), \
name##_buffer)
/**
* 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.
*
* The buffer will be release with kfifo_free().
*/
extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer,
unsigned int size);
/**
* kfifo_alloc - allocates a new FIFO internal buffer
* @fifo: the fifo to assign then new buffer
* @size: the size of the buffer to be allocated, this have to be a power of 2.
* @gfp_mask: get_free_pages mask, passed to kmalloc()
*
* This function dynamically allocates a new fifo internal buffer
*/
extern int kfifo_alloc(struct kfifo *fifo, unsigned long size, gfp_t gfp_mask);
/**
* kfifo_free - frees a dynamic allocated FIFO buffer
* @fifo: the fifo which buffer should be freed.
*/
extern void kfifo_free(struct kfifo *fifo);
/**
* kfifo_reset - removes the entire FIFO contents
* @fifo: the fifo to be emptied.
*/
static inline void kfifo_reset(struct kfifo *fifo)
{
fifo->out = fifo->in;
}
/**
* kfifo_used - returns the number of bytes currently used in the FIFO
* @fifo: the fifo to be used.
*/
static inline __must_check unsigned long kfifo_used(struct kfifo *fifo)
{
return fifo->in - fifo->out;
}
/**
* kfifo_size - returns the size of the fifo in bytes
* @fifo: the fifo to be used.
*/
static inline __must_check unsigned long kfifo_size(struct kfifo *fifo)
{
return fifo->size;
}
/**
* kfifo_empty - returns true if the fifo is empty
* @fifo: the fifo to be used.
*/
static inline __must_check int kfifo_empty(struct kfifo *fifo)
{
return fifo->in == fifo->out;
}
/**
* kfifo_is_full - returns true if the fifo is full
* @fifo: the fifo to be used.
*/
static inline __must_check int kfifo_is_full(struct kfifo *fifo)
{
return kfifo_used(fifo) == kfifo_size(fifo);
}
/**
* kfifo_avail - returns the number of bytes available in the FIFO
* @fifo: the fifo to be used.
*/
static inline __must_check unsigned long kfifo_avail(struct kfifo *fifo)
{
return kfifo_size(fifo) - kfifo_used(fifo);
}
/**
* __kfifo_add_out internal helper function for updating the out offset
*/
static inline void __kfifo_add_out(struct kfifo *fifo,
unsigned long off)
{
smp_mb();
fifo->out += off;
}
/**
* __kfifo_add_in internal helper function for updating the in offset
*/
static inline void __kfifo_add_in(struct kfifo *fifo,
unsigned long off)
{
smp_wmb();
fifo->in += off;
}
/**
* __kfifo_off internal helper function for calculating the index of a
* given offeset
*/
static inline unsigned long __kfifo_off(struct kfifo *fifo, unsigned long off)
{
return off & (fifo->size-1);
}
/**
* __kfifo_peek_n internal helper function for determinate the length of
* the next record in the fifo
*/
static inline unsigned long __kfifo_peek_n(struct kfifo *fifo,
unsigned long recsize)
{
#define KFIFO_GET_MOD(fifo, off, shift) \
((fifo)->buffer[__kfifo_off((fifo), (fifo)->out+(off))] <<
(shift))
unsigned long l;
l = KFIFO_GET_MOD(fifo, 0, 0);
if (unlikely(--recsize))
l |= KFIFO_GET_MOD(fifo, 1, 8);
return l;
}
/**
* __kfifo_poke_n internal helper function for storing the length of
* the next record into the fifo
*/
static inline void __kfifo_poke_n(struct kfifo *fifo,
unsigned long recsize, unsigned long n)
{
#define KFIFO_PUT(fifo, off, val, shift) \
(fifo)->buffer[__kfifo_off((fifo), (fifo)->in+(off))] = \
(unsigned char)((val) >> (shift))
KFIFO_PUT(fifo, 0, n, 0);
if (unlikely(--recsize))
KFIFO_PUT(fifo, 1, n, 8);
}
/**
* __kfifo_put... internal functions for put date into the fifo
* do not call it directly, use kfifo_put() instead
*/
extern unsigned long __kfifo_put_notrim(struct kfifo *fifo,
const unsigned char *from, unsigned long n, unsigned long recsize,
unsigned long *total);
extern unsigned long __kfifo_put_trim(struct kfifo *fifo,
const unsigned char *from, unsigned long n, unsigned long recsize,
unsigned long *total);
extern unsigned long __kfifo_put_generic(struct kfifo *fifo,
const unsigned char *from, unsigned long n, unsigned long recsize,
unsigned long flags, unsigned long *total);
static inline unsigned long __kfifo_put(struct kfifo *fifo,
const unsigned char *from, unsigned long n,
unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
if (!total)
total = &t;
if (flags)
ret = __kfifo_put_notrim(fifo, from, n, 0, total);
else
ret = __kfifo_put_trim(fifo, from, n, 0, total);
if (likely(ret == 0))
__kfifo_add_in(fifo, *total);
return ret;
}
static inline unsigned long __kfifo_put_n(struct kfifo *fifo,
const unsigned char *from, unsigned long n,
unsigned long recsize, unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
if (!total)
total = &t;
if (flags)
ret = __kfifo_put_notrim(fifo, from, n, recsize, total);
else
ret = __kfifo_put_trim(fifo, from, n, recsize, total);
if (likely(ret == 0)) {
__kfifo_poke_n(fifo, recsize, *total);
__kfifo_add_in(fifo, recsize + *total);
}
return ret;
}
/**
* kfifo_put - puts some data into the FIFO without locking
* @fifo: the fifo to be used.
* @from: the data to be added.
* @n: the length of the data to be added.
*
* This function copies at most @n bytes from the @from into
* the FIFO depending and returns the number of copied bytes.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
* This function is for compatibility reasons due the old kfifo API
*/
extern __must_check unsigned long kfifo_put(struct kfifo *fifo,
unsigned char *from, unsigned long n);
/**
* kfifo_put_rec - puts some record data into the FIFO without locking
* @fifo: the fifo to be used.
* @from: the data to be added.
* @n: the length of the data to be added.
* @recsize: size of record field
* @flags: KFIFO_F_NOTRIM = do not cut off if the record is to long
* @total: pointer where the total number of copied bytes should stored
*
* This function copies at most @n bytes from the @from into
* the FIFO depending @flags argument, and returns the number of
* bytes which cannot be copied.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned long kfifo_put_rec(struct kfifo *fifo,
unsigned char *from, unsigned long n, unsigned long recsize,
unsigned long flags, unsigned long *total)
{
if (__builtin_constant_p(recsize) && __builtin_constant_p(flags)) {
if (!recsize)
return __kfifo_put(fifo, from, n, flags, total);
return __kfifo_put_n(fifo, from, n, recsize, flags, total);
}
return __kfifo_put_generic(fifo, from, n, recsize, flags, total);
}
/**
* __kfifo_get... internal functions for get date from the fifo
* do not call it directly, use kfifo_get() instead
*/
extern unsigned long __kfifo_get_notrim(struct kfifo *fifo,
unsigned char *to, unsigned long n, unsigned long reclen,
unsigned long recsize, unsigned long *total);
extern unsigned long __kfifo_get_trim(struct kfifo *fifo,
unsigned char *to, unsigned long n, unsigned long reclen,
unsigned long recsize, unsigned long *total);
extern unsigned long __kfifo_get_generic(struct kfifo *fifo,
unsigned char *to, unsigned long n, unsigned long reclen,
unsigned long recsize, unsigned long *total);
static inline unsigned long __kfifo_get(struct kfifo *fifo,
unsigned char *to, unsigned long n,
unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
unsigned long l = kfifo_used(fifo);
if (!total)
total = &t;
if (unlikely(flags))
ret = __kfifo_get_notrim(fifo, to, n, l, 0, total);
else
ret = __kfifo_get_trim(fifo, to, n, l, 0, total);
if (likely(ret == 0))
__kfifo_add_out(fifo, *total);
return ret;
}
static inline unsigned long __kfifo_get_n(struct kfifo *fifo,
unsigned char *to, unsigned long n,
unsigned long recsize, unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
unsigned long l;
if (!total)
total = &t;
l = __kfifo_peek_n(fifo, recsize);
if (flags)
ret = __kfifo_get_notrim(fifo, to, n, l, recsize, total);
else
ret = __kfifo_get_trim(fifo, to, n, l, recsize, total);
if (likely(ret == 0))
__kfifo_add_out(fifo, recsize + l);
return ret;
}
/**
* kfifo_get - gets some data from the FIFO without locking
* @fifo: the fifo to be used.
* @to: where the data must be copied.
* @n: the size of the destination buffer.
*
* This function copies at most @n bytes from the @to into and returns
* the number of copied bytes
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
* This function is for compatibility reasons due the old kfifo API
*/
extern __must_check unsigned long kfifo_get(struct kfifo *fifo,
unsigned char *to, unsigned long n);
/**
* kfifo_get_rec - gets some record data from the FIFO without locking
* @fifo: the fifo to be used.
* @to: where the data must be copied.
* @n: the size of the destination buffer.
* @recsize: size of record field
* @flags: KFIFO_F_NOTRIM = do not cut off if the record is to long
* @total: pointer where the total number of copied bytes should stored
*
* This function copies at most @n bytes from the @to into
* the FIFO depending on @flags argument, and returns the number of
* bytes which cannot be copied.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned long kfifo_get_rec(struct kfifo *fifo,
unsigned char *to, unsigned long n, unsigned long recsize,
unsigned long flags, unsigned long *total)
{
if (__builtin_constant_p(recsize) && __builtin_constant_p(flags)) {
if (!recsize)
return __kfifo_get(fifo, to, n, flags, total);
return __kfifo_get_n(fifo, to, n, recsize, flags, total);
}
return __kfifo_get_generic(fifo, to, n, recsize, flags, total);
}
/**
* __kfifo_from_user... internal functions for transfer from user space into the
* fifo. do not call it directly, use kfifo_from_user() instead
*/
extern unsigned long __kfifo_from_user_notrim(struct kfifo *fifo,
const void __user *from, unsigned long n, unsigned long recsize,
unsigned long *total);
extern unsigned long __kfifo_from_user_trim(struct kfifo *fifo,
const void __user *from, unsigned long n, unsigned long recsize,
unsigned long *total);
extern unsigned long __kfifo_from_user_generic(struct kfifo *fifo,
const void __user *from, unsigned long n, unsigned long recsize,
unsigned long flags, unsigned long *total);
static inline unsigned long __kfifo_from_user(struct kfifo *fifo,
const void __user *from, unsigned long n,
unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
if (!total)
total = &t;
if (flags)
ret = __kfifo_from_user_notrim(fifo, from, n, 0, total);
else
ret = __kfifo_from_user_trim(fifo, from, n, 0, total);
if (likely(ret == 0))
__kfifo_add_in(fifo, *total);
return ret;
}
static inline unsigned long __kfifo_from_user_n(struct kfifo *fifo,
const void __user *from, unsigned long n,
unsigned long recsize, unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
if (!total)
total = &t;
if (flags)
ret = __kfifo_from_user_notrim(fifo, from, n, recsize, total);
else
ret = __kfifo_from_user_trim(fifo, from, n, recsize, total);
if (likely(ret == 0)) {
__kfifo_poke_n(fifo, recsize, *total);
__kfifo_add_in(fifo, recsize + *total);
}
return ret;
}
/**
* kfifo_from_user - puts some data from user space into the FIFO
* @fifo: the fifo to be used.
* @from: pointer to the data to be added.
* @n: the length of the data to be added.
* @recsize: size of record field
* @flags: KFIFO_F_NOTRIM = do not cut off if the record is to long
* @total: pointer where the total number of copied bytes should stored
*
* This function copies at most @n bytes from the @from into
* the FIFO depending on @flags argument, and returns the number of
* bytes which cannot be copied.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned long kfifo_from_user(struct kfifo *fifo,
const void __user *from, unsigned long n, unsigned long recsize,
unsigned long flags, unsigned long *total)
{
if (__builtin_constant_p(recsize) && __builtin_constant_p(flags)) {
if (!recsize)
return __kfifo_from_user(fifo, from, n, flags, total);
return __kfifo_from_user_n(fifo, from, n, recsize, flags,
total);
}
return __kfifo_from_user_generic(fifo, from, n, recsize, flags, total);
}
/**
* __kfifo_to_user... internal functions for transfer fifo data into user space
* do not call it directly, use kfifo_to_user() instead
*/
extern unsigned long __kfifo_to_user_notrim(struct kfifo *fifo,
void __user *to, unsigned long n, unsigned long reclen,
unsigned long recsize, unsigned long *total);
extern unsigned long __kfifo_to_user_trim(struct kfifo *fifo,
void __user *to, unsigned long n, unsigned long reclen,
unsigned long recsize, unsigned long *total);
extern unsigned long __kfifo_to_user_generic(struct kfifo *fifo,
void __user *to, unsigned long n, unsigned long recsize,
unsigned long flags, unsigned long *total);
static inline unsigned long __kfifo_to_user(struct kfifo *fifo,
void __user *to, unsigned long n,
unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
unsigned long l = kfifo_used(fifo);
if (!total)
total = &t;
if (unlikely(flags))
ret = __kfifo_to_user_notrim(fifo, to, n, l, 0, total);
else
ret = __kfifo_to_user_trim(fifo, to, n, l, 0, total);
if (likely(ret == 0))
__kfifo_add_out(fifo, *total);
return ret;
}
static inline unsigned long __kfifo_to_user_n(struct kfifo *fifo,
void __user *to, unsigned long n,
unsigned long recsize, unsigned long flags, unsigned long *total)
{
unsigned long ret;
unsigned long t;
unsigned long l;
if (!total)
total = &t;
l = __kfifo_peek_n(fifo, recsize);
if (flags)
ret = __kfifo_to_user_notrim(fifo, to, n, l, recsize, total);
else
ret = __kfifo_to_user_trim(fifo, to, n, l, recsize, total);
if (likely(ret == 0))
__kfifo_add_out(fifo, recsize + l);
return ret;
}
/**
* kfifo_to_user - gets data from the FIFO and write it to user space
* @fifo: the fifo to be used.
* @to: where the data must be copied.
* @n: the size of the destination buffer.
* @recsize: size of record field
* @flags: KFIFO_F_NOTRIM = do not cut off if the record is to long
* @total: pointer where the total number of copied bytes should stored
*
* This function copies at most @n bytes from the FIFO into the
* @to depending on @flags argument.
* In case of an error, the function returns the number of bytes which cannot
* be copied.
* - If the flags KFIFO_F_NOTRIM is set and the returned value is greater than
* the n parameter this means that there is not enough space to copy the
* whole record
* - Otherwise this means that the copy_to_user() functions has failed.
*
* Note that with only one concurrent reader and one concurrent
* writer, you don't need extra locking to use these functions.
*/
static inline __must_check unsigned long kfifo_to_user(struct kfifo *fifo,
void __user *to, unsigned long n, unsigned long recsize,
unsigned long flags, unsigned long *total)
{
if (__builtin_constant_p(recsize) && __builtin_constant_p(flags)) {
if (!recsize)
return __kfifo_to_user(fifo, to, n, flags, total);
return __kfifo_to_user_n(fifo, to, n, recsize, flags, total);
}
return __kfifo_to_user_generic(fifo, to, n, recsize, flags, total);
}
/**
* __kfifo_peek... internal functions for peek into the next fifo record
* do not call it directly, use kfifo_peek() instead
*/
extern unsigned long __kfifo_peek_generic(struct kfifo *fifo,
unsigned long recsize);
static inline unsigned long __kfifo_peek(struct kfifo *fifo)
{
return kfifo_used(fifo);
}
/**
* kfifo_peek - gets the size of the next FIFO record data
* @fifo: the fifo to be used.
* @recsize: size of record field
*
* This function returns the size of the next FIFO record in number of bytes
*/
static inline __must_check unsigned long kfifo_peek(struct kfifo *fifo,
unsigned long recsize)
{
if (__builtin_constant_p(recsize)) {
if (!recsize)
return __kfifo_peek(fifo);
return __kfifo_peek_n(fifo, recsize);
}
return __kfifo_peek_generic(fifo, recsize);
}
#endif
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"open-iscsi" group.
To post to this group, send email to open-iscsi@googlegroups.com
To unsubscribe from this group, send email to
open-iscsi+unsubscr...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/open-iscsi
-~----------~----~----~----~------~----~------~--~---
