1 /*
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * $FreeBSD$
26 */
27
28 #ifndef _SYS_CCOMPAT_H
29 #define _SYS_CCOMPAT_H
30
31 struct hlist_node {
32 struct hlist_node *next, **pprev;
33 };
34
35 struct hlist_head {
36 struct hlist_node *first;
37 };
38
39 typedef struct {
40 volatile int counter;
41 } atomic_t;
42
43 #define hlist_for_each(p, head) \
44 for (p = (head)->first; p; p = (p)->next)
45
46 #define hlist_entry(ptr, type, field) container_of(ptr, type, field)
47
48 #define container_of(ptr, type, member) \
49 /* CSTYLED */ \
50 ({ \
51 const __typeof(((type *)0)->member) *__p = (ptr); \
52 (type *)((uintptr_t)__p - offsetof(type, member)); \
53 })
54
55 static inline void
hlist_add_head(struct hlist_node * n,struct hlist_head * h)56 hlist_add_head(struct hlist_node *n, struct hlist_head *h)
57 {
58 n->next = h->first;
59 if (h->first != NULL)
60 h->first->pprev = &n->next;
61 WRITE_ONCE(h->first, n);
62 n->pprev = &h->first;
63 }
64
65 static inline void
hlist_del(struct hlist_node * n)66 hlist_del(struct hlist_node *n)
67 {
68 WRITE_ONCE(*(n->pprev), n->next);
69 if (n->next != NULL)
70 n->next->pprev = n->pprev;
71 }
72 /* BEGIN CSTYLED */
73 #define HLIST_HEAD_INIT { }
74 #define HLIST_HEAD(name) struct hlist_head name = HLIST_HEAD_INIT
75 #define INIT_HLIST_HEAD(head) (head)->first = NULL
76
77 #define INIT_HLIST_NODE(node) \
78 do { \
79 (node)->next = NULL; \
80 (node)->pprev = NULL; \
81 } while (0)
82
83 /* END CSTYLED */
84 static inline int
atomic_read(const atomic_t * v)85 atomic_read(const atomic_t *v)
86 {
87 return (READ_ONCE(v->counter));
88 }
89
90 static inline int
atomic_inc(atomic_t * v)91 atomic_inc(atomic_t *v)
92 {
93 return (atomic_fetchadd_int(&v->counter, 1) + 1);
94 }
95
96 static inline int
atomic_dec(atomic_t * v)97 atomic_dec(atomic_t *v)
98 {
99 return (atomic_fetchadd_int(&v->counter, -1) - 1);
100 }
101 #endif
102