1 /*-
2 * Copyright (c) 1982, 1986, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)socketvar.h 8.3 (Berkeley) 2/19/95
30 * $FreeBSD: src/sys/sys/socketvar.h,v 1.46.2.10 2003/08/24 08:24:39 hsu Exp $
31 */
32
33 #ifndef _SYS_SOCKETVAR2_H_
34 #define _SYS_SOCKETVAR2_H_
35
36 #ifndef _KERNEL
37 #error "This file should not be included by userland programs."
38 #endif
39
40 #ifndef _SYS_SOCKETVAR_H_
41 #include <sys/socketvar.h>
42 #endif
43 #ifndef _SYS_SYSTM_H_
44 #include <sys/systm.h>
45 #endif
46 #include <machine/atomic.h>
47
48 /*
49 * Acquire a lock on a signalsockbuf, sleep if the lock is already held.
50 * The sleep is interruptable unless SSB_NOINTR is set in the ssb.
51 *
52 * We also acquire the token on success. This token is used to interlock
53 * frontend/backend operations until the sockbuf itself can be made mpsafe.
54 *
55 * Returns 0 on success, non-zero if the lock could not be acquired.
56 */
57 #ifdef MALLOC_DEFINE
58 static __inline int
ssb_lock(struct signalsockbuf * ssb,int wf)59 ssb_lock(struct signalsockbuf *ssb, int wf)
60 {
61 uint32_t flags;
62
63 for (;;) {
64 flags = ssb->ssb_flags;
65 cpu_ccfence();
66 if (flags & SSB_LOCK) {
67 if (wf == M_WAITOK)
68 return _ssb_lock(ssb);
69 return EWOULDBLOCK;
70 }
71 if (atomic_cmpset_int(&ssb->ssb_flags, flags, flags|SSB_LOCK)) {
72 lwkt_gettoken(&ssb->ssb_token);
73 return(0);
74 }
75 }
76 }
77 #endif
78
79 /*
80 * Release a previously acquired lock on a signalsockbuf.
81 *
82 * Interlocked wakeup if SSB_WANT was also set.
83 */
84 static __inline void
ssb_unlock(struct signalsockbuf * ssb)85 ssb_unlock(struct signalsockbuf *ssb)
86 {
87 uint32_t flags;
88
89 KKASSERT(ssb->ssb_flags & SSB_LOCK);
90 lwkt_reltoken(&ssb->ssb_token);
91 for (;;) {
92 flags = ssb->ssb_flags;
93 cpu_ccfence();
94 if (atomic_cmpset_int(&ssb->ssb_flags, flags,
95 flags & ~(SSB_LOCK | SSB_WANT))) {
96 if (flags & SSB_WANT)
97 wakeup(&ssb->ssb_flags);
98 break;
99 }
100 }
101 }
102
103 static __inline void
sosetstate(struct socket * so,short state)104 sosetstate(struct socket *so, short state)
105 {
106 atomic_set_short(&so->so_state, state);
107 }
108
109 static __inline void
soclrstate(struct socket * so,short state)110 soclrstate(struct socket *so, short state)
111 {
112 atomic_clear_short(&so->so_state, state);
113 }
114
115 static __inline void
soreference(struct socket * so)116 soreference(struct socket *so)
117 {
118 /*
119 * 0 -> 1 transition will happen on an aborted
120 * socket, which is left on the so_comp queue,
121 * e.g. accept(2) the aborted socket, or when
122 * the listen(2) socket owning the so_comp queue
123 * is closed.
124 */
125 atomic_add_int(&so->so_refs, 1);
126 }
127
128 #endif
129