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 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 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 104 sosetstate(struct socket *so, short state) 105 { 106 atomic_set_short(&so->so_state, state); 107 } 108 109 static __inline void 110 soclrstate(struct socket *so, short state) 111 { 112 atomic_clear_short(&so->so_state, state); 113 } 114 115 static __inline void 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