xref: /freebsd/sys/kern/subr_bufring.c (revision d7d962ead0b6e5e8a39202d0590022082bf5bfb6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2007, 2008 Kip Macy <kmacy@freebsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * 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 AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/ktr.h>
37 #include <sys/buf_ring.h>
38 
39 struct buf_ring *
40 buf_ring_alloc(int count, struct malloc_type *type, int flags, struct mtx *lock)
41 {
42 	struct buf_ring *br;
43 
44 	KASSERT(powerof2(count), ("buf ring must be size power of 2"));
45 
46 	br = malloc(sizeof(struct buf_ring) + count*sizeof(caddr_t),
47 	    type, flags|M_ZERO);
48 	if (br == NULL)
49 		return (NULL);
50 #ifdef DEBUG_BUFRING
51 	br->br_lock = lock;
52 #endif
53 	br->br_prod_size = br->br_cons_size = count;
54 	br->br_prod_mask = br->br_cons_mask = count-1;
55 	br->br_prod_head = br->br_cons_head = 0;
56 	br->br_prod_tail = br->br_cons_tail = 0;
57 
58 	return (br);
59 }
60 
61 void
62 buf_ring_free(struct buf_ring *br, struct malloc_type *type)
63 {
64 	free(br, type);
65 }
66