subr_bufring.c

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/*-
 * 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. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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("$BSDSUniX$");


#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);
}