From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- include/linux/kfifo.h | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 157 insertions(+) create mode 100644 include/linux/kfifo.h (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h new file mode 100644 index 000000000000..c27cd428d269 --- /dev/null +++ b/include/linux/kfifo.h @@ -0,0 +1,157 @@ +/* + * A simple kernel FIFO implementation. + * + * Copyright (C) 2004 Stelian Pop + * + * 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 + +#ifdef __KERNEL__ + +#include +#include + +struct kfifo { + unsigned char *buffer; /* the buffer holding the data */ + unsigned int size; /* the size of the allocated buffer */ + unsigned int in; /* data is added at offset (in % size) */ + unsigned int out; /* data is extracted from off. (out % size) */ + spinlock_t *lock; /* protects concurrent modifications */ +}; + +extern struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size, + unsigned int __nocast gfp_mask, spinlock_t *lock); +extern struct kfifo *kfifo_alloc(unsigned int size, unsigned int __nocast gfp_mask, + spinlock_t *lock); +extern void kfifo_free(struct kfifo *fifo); +extern unsigned int __kfifo_put(struct kfifo *fifo, + unsigned char *buffer, unsigned int len); +extern unsigned int __kfifo_get(struct kfifo *fifo, + unsigned char *buffer, unsigned int len); + +/** + * __kfifo_reset - removes the entire FIFO contents, no locking version + * @fifo: the fifo to be emptied. + */ +static inline void __kfifo_reset(struct kfifo *fifo) +{ + fifo->in = fifo->out = 0; +} + +/** + * kfifo_reset - removes the entire FIFO contents + * @fifo: the fifo to be emptied. + */ +static inline void kfifo_reset(struct kfifo *fifo) +{ + unsigned long flags; + + spin_lock_irqsave(fifo->lock, flags); + + __kfifo_reset(fifo); + + spin_unlock_irqrestore(fifo->lock, flags); +} + +/** + * kfifo_put - puts some data into the FIFO + * @fifo: the fifo to be used. + * @buffer: the data to be added. + * @len: the length of the data to be added. + * + * This function copies at most 'len' bytes from the 'buffer' into + * the FIFO depending on the free space, and returns the number of + * bytes copied. + */ +static inline unsigned int kfifo_put(struct kfifo *fifo, + unsigned char *buffer, unsigned int len) +{ + unsigned long flags; + unsigned int ret; + + spin_lock_irqsave(fifo->lock, flags); + + ret = __kfifo_put(fifo, buffer, len); + + spin_unlock_irqrestore(fifo->lock, flags); + + return ret; +} + +/** + * kfifo_get - gets some data from the FIFO + * @fifo: the fifo to be used. + * @buffer: where the data must be copied. + * @len: the size of the destination buffer. + * + * This function copies at most 'len' bytes from the FIFO into the + * 'buffer' and returns the number of copied bytes. + */ +static inline unsigned int kfifo_get(struct kfifo *fifo, + unsigned char *buffer, unsigned int len) +{ + unsigned long flags; + unsigned int ret; + + spin_lock_irqsave(fifo->lock, flags); + + ret = __kfifo_get(fifo, buffer, len); + + /* + * optimization: if the FIFO is empty, set the indices to 0 + * so we don't wrap the next time + */ + if (fifo->in == fifo->out) + fifo->in = fifo->out = 0; + + spin_unlock_irqrestore(fifo->lock, flags); + + return ret; +} + +/** + * __kfifo_len - returns the number of bytes available in the FIFO, no locking version + * @fifo: the fifo to be used. + */ +static inline unsigned int __kfifo_len(struct kfifo *fifo) +{ + return fifo->in - fifo->out; +} + +/** + * kfifo_len - returns the number of bytes available in the FIFO + * @fifo: the fifo to be used. + */ +static inline unsigned int kfifo_len(struct kfifo *fifo) +{ + unsigned long flags; + unsigned int ret; + + spin_lock_irqsave(fifo->lock, flags); + + ret = __kfifo_len(fifo); + + spin_unlock_irqrestore(fifo->lock, flags); + + return ret; +} + +#else +#warning "don't include kernel headers in userspace" +#endif /* __KERNEL__ */ +#endif -- cgit v1.2.1