sys/sys/socketvar2.h

   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