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 _SYS_SOCKETVAR_H_
  37 #include <sys/socketvar.h>
  38 #endif
  39 #ifndef _SYS_SYSTM_H_
  40 #include <sys/systm.h>
  41 #endif
  42 #ifndef _SYS_MALLOC_H_
  43 #include <sys/malloc.h>
  44 #endif
  45 #include <machine/atomic.h>
  46
  47 /*
  48  * Acquire a lock on a signalsockbuf, sleep if the lock is already held.
  49  * The sleep is interruptable unless SSB_NOINTR is set in the ssb.
  50  *
  51  * We also acquire the token on success.  This token is used to interlock
  52  * frontend/backend operations until the sockbuf itself can be made mpsafe.
  53  *
  54  * Returns 0 on success, non-zero if the lock could not be acquired.
  55  */
  56 static __inline int
  57 ssb_lock(struct signalsockbuf *ssb, int wf)
  58 {
  59         uint32_t flags;
  60
  61         for (;;) {
  62                 flags = ssb->ssb_flags;
  63                 cpu_ccfence();
  64                 if (flags & SSB_LOCK) {
  65                         if (wf == M_WAITOK)
  66                                 return _ssb_lock(ssb);
  67                         return EWOULDBLOCK;
  68                 }
  69                 if (atomic_cmpset_int(&ssb->ssb_flags, flags, flags|SSB_LOCK)) {
  70                         lwkt_gettoken(&ssb->ssb_token);
  71                         return(0);
  72                 }
  73         }
  74 }
  75
  76 /*
  77  * Release a previously acquired lock on a signalsockbuf.
  78  *
  79  * Interlocked wakeup if SSB_WANT was also set.
  80  */
  81 static __inline void
  82 ssb_unlock(struct signalsockbuf *ssb)
  83 {
  84         uint32_t flags;
  85
  86         KKASSERT(ssb->ssb_flags & SSB_LOCK);
  87         lwkt_reltoken(&ssb->ssb_token);
  88         for (;;) {
  89                 flags = ssb->ssb_flags;
  90                 cpu_ccfence();
  91                 if (atomic_cmpset_int(&ssb->ssb_flags, flags,
  92                                       flags & ~(SSB_LOCK | SSB_WANT))) {
  93                         if (flags & SSB_WANT)
  94                                 wakeup(&ssb->ssb_flags);
  95                         break;
  96                 }
  97         }
  98 }
  99
 100 static __inline void
 101 sosetstate(struct socket *so, short state)
 102 {
 103         atomic_set_short(&so->so_state, state);
 104 }
 105
 106 static __inline void
 107 soclrstate(struct socket *so, short state)
 108 {
 109         atomic_clear_short(&so->so_state, state);
 110 }
 111
 112 static __inline void
 113 soreference(struct socket *so)
 114 {
 115         /*
 116          * 0 -> 1 transition will happen on an aborted
 117          * socket, which is left on the so_comp queue,
 118          * e.g. accept(2) the aborted socket, or when
 119          * the listen(2) socket owning the so_comp queue
 120          * is closed.
 121          */
 122         atomic_add_int(&so->so_refs, 1);
 123 }
 124
 125 #endif