1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (C) 2013-2014 Vincenzo Maffione
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/*
30 * $FreeBSD$
31 */
32
33
34#ifndef _NET_NETMAP_MBQ_H__
35#define _NET_NETMAP_MBQ_H__
36
37/*
38 * These function implement an mbuf tailq with an optional lock.
39 * The base functions act ONLY ON THE QUEUE, whereas the "safe"
40 * variants (mbq_safe_*) also handle the lock.
41 */
42
43/* XXX probably rely on a previous definition of SPINLOCK_T */
44#ifdef linux
45#define SPINLOCK_T  safe_spinlock_t
46#elif defined (_WIN32)
47#define SPINLOCK_T 	win_spinlock_t
48#else
49#define SPINLOCK_T  struct mtx
50#endif
51
52/* A FIFO queue of mbufs with an optional lock. */
53struct mbq {
54    struct mbuf *head;
55    struct mbuf *tail;
56    int count;
57    SPINLOCK_T lock;
58};
59
60/* We should clarify whether init can be used while
61 * holding a lock, and whether mbq_safe_destroy() is a NOP.
62 */
63void mbq_init(struct mbq *q);
64void mbq_fini(struct mbq *q);
65void mbq_enqueue(struct mbq *q, struct mbuf *m);
66struct mbuf *mbq_dequeue(struct mbq *q);
67void mbq_purge(struct mbq *q);
68
69static inline struct mbuf *
70mbq_peek(struct mbq *q)
71{
72	return q->head;
73}
74
75static inline void
76mbq_lock(struct mbq *q)
77{
78	mtx_lock_spin(&q->lock);
79}
80
81static inline void
82mbq_unlock(struct mbq *q)
83{
84	mtx_unlock_spin(&q->lock);
85}
86
87
88void mbq_safe_init(struct mbq *q);
89void mbq_safe_fini(struct mbq *q);
90void mbq_safe_enqueue(struct mbq *q, struct mbuf *m);
91struct mbuf *mbq_safe_dequeue(struct mbq *q);
92void mbq_safe_purge(struct mbq *q);
93
94static inline unsigned int mbq_len(struct mbq *q)
95{
96    return q->count;
97}
98
99#endif /* _NET_NETMAP_MBQ_H_ */
100