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* fs/Kconfig: move configfs outAlexey Dobriyan2009-01-22
* fs/Kconfig: move sysfs outAlexey Dobriyan2009-01-22
* fs/Kconfig: move ntfs outAlexey Dobriyan2009-01-22
* fs/Kconfig: move fat outAlexey Dobriyan2009-01-22
* fs/Kconfig: move iso9660, udf outAlexey Dobriyan2009-01-22
* fs/Kconfig: move fuse outAlexey Dobriyan2009-01-22
* fs/Kconfig: move autofs, autofs4 outAlexey Dobriyan2009-01-22
* fs/Kconfig: move btrfs outAlexey Dobriyan2009-01-22
* fs/Kconfig: move ocfs2 outAlexey Dobriyan2009-01-22
* fs/Kconfig: move jfs outAlexey Dobriyan2009-01-22
* fs/Kconfig: move reiserfs outAlexey Dobriyan2009-01-22
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds2009-01-16
|\
| * Btrfs: fix ioctl arg size (userland incompatible change!)Chris Mason2009-01-16
| * Btrfs: Clear the device->running_pending flag before bailing on congestionChris Mason2009-01-16
* | ext2: also update the inode on disk when dir is IS_DIRSYNCJan Kara2009-01-15
* | btrfs & squashfs: Move btrfs and squashfsto's magic number to <linux/magic.h>Qinghuang Feng2009-01-15
* | Merge branch 'syscalls' of git://git390.osdl.marist.edu/pub/scm/linux-2.6Linus Torvalds2009-01-14
|\ \
| * | [CVE-2009-0029] System call wrappers part 33Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 32Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 31Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 30Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 29Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 28Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 27Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 23Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 21Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 20Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 19Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 17Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 16Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 15Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 14Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 13Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 12Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 11Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 10Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrappers part 09Heiko Carstens2009-01-14
| * | [CVE-2009-0029] System call wrapper special casesHeiko Carstens2009-01-14
| * | [CVE-2009-0029] Make sys_pselect7 staticHeiko Carstens2009-01-14
| * | [CVE-2009-0029] Remove __attribute__((weak)) from sys_pipe/sys_pipe2Heiko Carstens2009-01-14
| * | [CVE-2009-0029] Rename old_readdir to sys_old_readdirHeiko Carstens2009-01-14
| * | [CVE-2009-0029] Convert all system calls to return a longHeiko Carstens2009-01-14
* | | Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into f...Lachlan McIlroy2009-01-14
|\| |
| * | Fix timeouts in sys_pselect7Bernd Schmidt2009-01-13
| * | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tei...Linus Torvalds2009-01-12
| |\ \
| | * | dlm: change rsbtbl rwlock to spinlockDavid Teigland2009-01-08
| | * | dlm: fix seq_file usage in debugfs lock dumpDavid Teigland2009-01-08
| * | | btrfs: fix for write_super_lockfs/unlockfs error handlingLinus Torvalds2009-01-10
| * | | filesystem freeze: remove XFS specific ioctl interfaces for freeze featureTakashi Sato2009-01-09
| * | | filesystem freeze: implement generic freeze featureTakashi Sato2009-01-09
                                                                












                                                                  






                                                                






                                                                        






                                                             











                                                                 

                                                                 










                                                                 






                                                               






                                                                           






                                                                  




                           
/*
 * A simple kernel FIFO implementation.
 *
 * Copyright (C) 2004 Stelian Pop <stelian@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.
 *
 */

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

/**
 * kfifo_init - allocates a new FIFO using a preallocated buffer
 * @buffer: the preallocated buffer to be used.
 * @size: the size of the internal buffer, this have to be a power of 2.
 * @gfp_mask: get_free_pages mask, passed to kmalloc()
 * @lock: the lock to be used to protect the fifo buffer
 *
 * Do NOT pass the kfifo to kfifo_free() after use! Simply free the
 * &struct kfifo with kfree().
 */
struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size,
			 gfp_t gfp_mask, spinlock_t *lock)
{
	struct kfifo *fifo;

	/* size must be a power of 2 */
	BUG_ON(!is_power_of_2(size));

	fifo = kmalloc(sizeof(struct kfifo), gfp_mask);
	if (!fifo)
		return ERR_PTR(-ENOMEM);

	fifo->buffer = buffer;
	fifo->size = size;
	fifo->in = fifo->out = 0;
	fifo->lock = lock;

	return fifo;
}
EXPORT_SYMBOL(kfifo_init);

/**
 * kfifo_alloc - allocates a new FIFO and its internal buffer
 * @size: the size of the internal buffer to be allocated.
 * @gfp_mask: get_free_pages mask, passed to kmalloc()
 * @lock: the lock to be used to protect the fifo buffer
 *
 * The size will be rounded-up to a power of 2.
 */
struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, spinlock_t *lock)
{
	unsigned char *buffer;
	struct kfifo *ret;

	/*
	 * round up to the next power of 2, since our 'let the indices
	 * wrap' tachnique works only in this case.
	 */
	if (size & (size - 1)) {
		BUG_ON(size > 0x80000000);
		size = roundup_pow_of_two(size);
	}

	buffer = kmalloc(size, gfp_mask);
	if (!buffer)
		return ERR_PTR(-ENOMEM);

	ret = kfifo_init(buffer, size, gfp_mask, lock);

	if (IS_ERR(ret))
		kfree(buffer);

	return ret;
}
EXPORT_SYMBOL(kfifo_alloc);

/**
 * kfifo_free - frees the FIFO
 * @fifo: the fifo to be freed.
 */
void kfifo_free(struct kfifo *fifo)
{
	kfree(fifo->buffer);
	kfree(fifo);
}
EXPORT_SYMBOL(kfifo_free);

/**
 * __kfifo_put - puts some data into the FIFO, no locking version
 * @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.
 *
 * Note that with only one concurrent reader and one concurrent
 * writer, you don't need extra locking to use these functions.
 */
unsigned int __kfifo_put(struct kfifo *fifo,
			 unsigned char *buffer, unsigned int len)
{
	unsigned int l;

	len = min(len, fifo->size - fifo->in + fifo->out);

	/*
	 * Ensure that we sample the fifo->out index -before- we
	 * start putting bytes into the kfifo.
	 */

	smp_mb();

	/* first put the data starting from fifo->in to buffer end */
	l = min(len, fifo->size - (fifo->in & (fifo->size - 1)));
	memcpy(fifo->buffer + (fifo->in & (fifo->size - 1)), buffer, l);

	/* then put the rest (if any) at the beginning of the buffer */
	memcpy(fifo->buffer, buffer + l, len - l);

	/*
	 * Ensure that we add the bytes to the kfifo -before-
	 * we update the fifo->in index.
	 */

	smp_wmb();

	fifo->in += len;

	return len;
}
EXPORT_SYMBOL(__kfifo_put);

/**
 * __kfifo_get - gets some data from the FIFO, no locking version
 * @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.
 *
 * Note that with only one concurrent reader and one concurrent
 * writer, you don't need extra locking to use these functions.
 */
unsigned int __kfifo_get(struct kfifo *fifo,
			 unsigned char *buffer, unsigned int len)
{
	unsigned int l;

	len = min(len, fifo->in - fifo->out);

	/*
	 * Ensure that we sample the fifo->in index -before- we
	 * start removing bytes from the kfifo.
	 */

	smp_rmb();

	/* first get the data from fifo->out until the end of the buffer */
	l = min(len, fifo->size - (fifo->out & (fifo->size - 1)));
	memcpy(buffer, fifo->buffer + (fifo->out & (fifo->size - 1)), l);

	/* then get the rest (if any) from the beginning of the buffer */
	memcpy(buffer + l, fifo->buffer, len - l);

	/*
	 * Ensure that we remove the bytes from the kfifo -before-
	 * we update the fifo->out index.
	 */

	smp_mb();

	fifo->out += len;

	return len;
}
EXPORT_SYMBOL(__kfifo_get);