subr_bufring.c revision 185162 
1/**************************************************************************
2 *
3 * Copyright (c) 2007,2008 Kip Macy kmacy@freebsd.org
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright notice,
10 *    this list of conditions and the following disclaimer.
11 *
12 * 2. The name of Kip Macy nor the names of other
13 *    contributors may be used to endorse or promote products derived from
14 *    this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 *
29 ***************************************************************************/
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/sys/kern/subr_bufring.c 185162 2008-11-22 05:55:56Z kmacy $");
32
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/kernel.h>
37#include <sys/malloc.h>
38#include <sys/ktr.h>
39#include <sys/buf_ring.h>
40
41
42struct buf_ring *
43buf_ring_alloc(int count, struct malloc_type *type, int flags, struct mtx *lock)
44{
45	struct buf_ring *br;
46
47	KASSERT(powerof2(count), ("buf ring must be size power of 2"));
48
49	br = malloc(sizeof(struct buf_ring) + count*sizeof(caddr_t),
50	    type, flags|M_ZERO);
51	if (br == NULL)
52		return (NULL);
53#ifdef DEBUG_BUFRING
54	br->br_lock = lock;
55#endif
56	br->br_prod_size = br->br_cons_size = count;
57	br->br_prod_mask = br->br_cons_mask = count-1;
58	br->br_prod_head = br->br_cons_head = 0;
59	br->br_prod_tail = br->br_cons_tail = 0;
60
61	return (br);
62}
63
64void
65buf_ring_free(struct buf_ring *br, struct malloc_type *type)
66{
67	free(br, type);
68}
69