xref: /freebsd/sys/kern/subr_bufring.c (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/malloc.h>
33 #include <sys/ktr.h>
34 #include <sys/buf_ring.h>
35 
36 struct buf_ring *
37 buf_ring_alloc(int count, struct malloc_type *type, int flags, struct mtx *lock)
38 {
39 	struct buf_ring *br;
40 
41 	KASSERT(powerof2(count), ("buf ring must be size power of 2"));
42 
43 	br = malloc(sizeof(struct buf_ring) + count*sizeof(caddr_t),
44 	    type, flags|M_ZERO);
45 	if (br == NULL)
46 		return (NULL);
47 #ifdef DEBUG_BUFRING
48 	br->br_lock = lock;
49 #endif
50 	br->br_prod_size = br->br_cons_size = count;
51 	br->br_prod_mask = br->br_cons_mask = count-1;
52 	br->br_prod_head = br->br_cons_head = 0;
53 	br->br_prod_tail = br->br_cons_tail = 0;
54 
55 	return (br);
56 }
57 
58 void
59 buf_ring_free(struct buf_ring *br, struct malloc_type *type)
60 {
61 	free(br, type);
62 }
63