xref: /freebsd/sys/kern/subr_bufring.c (revision db7f0b974f2ab273540a458ab50929ccbb1aa581)

/**************************************************************************
 *
 * Copyright (c) 2007,2008 Kip Macy kmacy@freebsd.org
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. The name of Kip Macy nor the names of other
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *
 ***************************************************************************/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");


#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/ktr.h>
#include <sys/buf_ring.h>


struct buf_ring *
buf_ring_alloc(int count, struct malloc_type *type, int flags, struct mtx *lock)
{
	struct buf_ring *br;

	KASSERT(powerof2(count), ("buf ring must be size power of 2"));

	br = malloc(sizeof(struct buf_ring) + count*sizeof(caddr_t),
	    type, flags|M_ZERO);
	if (br == NULL)
		return (NULL);
#ifdef DEBUG_BUFRING
	br->br_lock = lock;
#endif
	br->br_prod_size = br->br_cons_size = count;
	br->br_prod_mask = br->br_cons_mask = count-1;
	br->br_prod_head = br->br_cons_head = 0;
	br->br_prod_tail = br->br_cons_tail = 0;

	return (br);
}

void
buf_ring_free(struct buf_ring *br, struct malloc_type *type)
{
	free(br, type);
}