drivers/char/nozomi/kfifo.h

   1 /*
   2  * A simple kernel FIFO implementation.
   3  *
   4  * Copyright (C) 2004 Stelian Pop <stelian@popies.net>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  *
  20  */
  21 #ifndef _LINUX_KFIFO_H
  22 #define _LINUX_KFIFO_H
  23
  24 #ifdef __KERNEL__
  25
  26 #include <linux/version.h>
  27
  28 //#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0)
  29 //#warning "Don't include this header in 2.6, use header supplied with kernel"
  30 //#endif
  31
  32 struct kfifo {
  33         unsigned char *buffer;  /* the buffer holding the data */
  34         unsigned int size;      /* the size of the allocated buffer */
  35         unsigned int in;        /* data is added at offset (in % size) */
  36         unsigned int out;       /* data is extracted from off. (out % size) */
  37 };
  38
  39 extern struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size, unsigned int gfp_mask, void *lock);
  40 extern struct kfifo *kfifo_alloc(unsigned int size, unsigned int gfp_mask, void *lock);
  41 extern void kfifo_free(struct kfifo *fifo);
  42 extern unsigned int __kfifo_put(struct kfifo *fifo, unsigned char *buffer, unsigned int len);
  43 extern unsigned int __kfifo_put_user(struct kfifo *fifo, unsigned char *buffer, unsigned int len);
  44 extern unsigned int __kfifo_get(struct kfifo *fifo,     unsigned char *buffer, unsigned int len);
  45
  46 /**
  47  * __kfifo_reset - removes the entire FIFO contents, no locking version
  48  * @fifo: the fifo to be emptied.
  49  */
  50 static inline void __kfifo_reset(struct kfifo *fifo)
  51 {
  52         fifo->in = fifo->out = 0;
  53 }
  54
  55 /**
  56  * __kfifo_len - returns the number of bytes available in the FIFO, no locking version
  57  * @fifo: the fifo to be used.
  58  */
  59 static inline unsigned int __kfifo_len(struct kfifo *fifo)
  60 {
  61         return fifo->in - fifo->out;
  62 }
  63
  64 #else
  65 #warning "don't include kernel headers in userspace"
  66 #endif /* __KERNEL__ */
  67 #endif