netmap_mbq.h revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (C) 2013-2014 Vincenzo Maffione. 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
8 * are met:
9 *   1. Redistributions of source code must retain the above copyright
10 *      notice, this list of conditions and the following disclaimer.
11 *   2. Redistributions in binary form must reproduce the above copyright
12 *      notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28/*
29 * $FreeBSD: stable/11/sys/dev/netmap/netmap_mbq.h 330897 2018-03-14 03:19:51Z eadler $
30 */
31
32
33#ifndef __NETMAP_MBQ_H__
34#define __NETMAP_MBQ_H__
35
36/*
37 * These function implement an mbuf tailq with an optional lock.
38 * The base functions act ONLY ON THE QUEUE, whereas the "safe"
39 * variants (mbq_safe_*) also handle the lock.
40 */
41
42/* XXX probably rely on a previous definition of SPINLOCK_T */
43#ifdef linux
44#define SPINLOCK_T  safe_spinlock_t
45#else
46#define SPINLOCK_T  struct mtx
47#endif
48
49/* A FIFO queue of mbufs with an optional lock. */
50struct mbq {
51    struct mbuf *head;
52    struct mbuf *tail;
53    int count;
54    SPINLOCK_T lock;
55};
56
57/* XXX "destroy" does not match "init" as a name.
58 * We should also clarify whether init can be used while
59 * holding a lock, and whether mbq_safe_destroy() is a NOP.
60 */
61void mbq_init(struct mbq *q);
62void mbq_destroy(struct mbq *q);
63void mbq_enqueue(struct mbq *q, struct mbuf *m);
64struct mbuf *mbq_dequeue(struct mbq *q);
65void mbq_purge(struct mbq *q);
66
67static inline void
68mbq_lock(struct mbq *q)
69{
70	mtx_lock_spin(&q->lock);
71}
72
73static inline void
74mbq_unlock(struct mbq *q)
75{
76	mtx_unlock_spin(&q->lock);
77}
78
79
80void mbq_safe_init(struct mbq *q);
81void mbq_safe_destroy(struct mbq *q);
82void mbq_safe_enqueue(struct mbq *q, struct mbuf *m);
83struct mbuf *mbq_safe_dequeue(struct mbq *q);
84void mbq_safe_purge(struct mbq *q);
85
86static inline unsigned int mbq_len(struct mbq *q)
87{
88    return q->count;
89}
90
91#endif /* __NETMAP_MBQ_H_ */
92