356 lines
14 KiB
C
356 lines
14 KiB
C
/* $NetBSD: lock.h,v 1.41 2000/11/24 03:59:09 chs Exp $ */
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/*-
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* Copyright (c) 1999, 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Ross Harvey.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1995
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* The Regents of the University of California. All rights reserved.
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*
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* This code contains ideas from software contributed to Berkeley by
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* Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
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* System project at Carnegie-Mellon University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)lock.h 8.12 (Berkeley) 5/19/95
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*/
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#ifndef _SYS_LOCK_H_
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#define _SYS_LOCK_H_
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#if defined(_KERNEL) && !defined(_LKM)
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#include "opt_lockdebug.h"
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#include "opt_multiprocessor.h"
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#endif
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#include <sys/queue.h>
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#include <machine/lock.h>
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/*
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* The simple lock. Provides a simple spinning mutex. Note the
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* member which is used in atomic operations must be aligned in
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* order for it to work on the widest range of processor types.
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*/
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struct simplelock {
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__cpu_simple_lock_t lock_data;
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#ifdef LOCKDEBUG
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const char *lock_file;
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const char *unlock_file;
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short lock_line;
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short unlock_line;
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TAILQ_ENTRY(simplelock) list;
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cpuid_t lock_holder; /* CPU ID */
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#endif
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};
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#ifdef LOCKDEBUG
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#define SIMPLELOCK_INITIALIZER { __SIMPLELOCK_UNLOCKED, NULL, NULL, 0, \
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0, { NULL, NULL }, LK_NOCPU }
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#else
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#define SIMPLELOCK_INITIALIZER { __SIMPLELOCK_UNLOCKED }
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#endif
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/* XXXCDC: kill typedefs later? */
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typedef struct simplelock simple_lock_data_t;
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typedef struct simplelock *simple_lock_t;
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typedef struct lock lock_data_t;
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typedef struct lock *lock_t;
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/*
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* The general lock structure. Provides for multiple shared locks,
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* upgrading from shared to exclusive, and sleeping/spinning until the
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* lock can be gained.
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*/
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struct lock {
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struct simplelock lk_interlock; /* lock on remaining fields */
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u_int lk_flags; /* see below */
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int lk_sharecount; /* # of accepted shared locks */
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short lk_exclusivecount; /* # of recursive exclusive locks */
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short lk_recurselevel; /* lvl above which recursion ok */
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int lk_waitcount; /* # of sleepers/spinners */
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/*
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* This is the sleep message for sleep locks, and a simple name
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* for spin locks.
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*/
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const char *lk_wmesg;
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union {
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struct {
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/* pid of exclusive lock holder */
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pid_t lk_sleep_lockholder;
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/* priority at which to sleep */
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int lk_sleep_prio;
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/* maximum sleep time (for tsleep) */
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int lk_sleep_timo;
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} lk_un_sleep;
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struct {
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/* CPU ID of exclusive lock holder */
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cpuid_t lk_spin_cpu;
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#if defined(LOCKDEBUG)
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TAILQ_ENTRY(lock) lk_spin_list;
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#endif
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} lk_un_spin;
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} lk_un;
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#define lk_lockholder lk_un.lk_un_sleep.lk_sleep_lockholder
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#define lk_prio lk_un.lk_un_sleep.lk_sleep_prio
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#define lk_timo lk_un.lk_un_sleep.lk_sleep_timo
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#define lk_cpu lk_un.lk_un_spin.lk_spin_cpu
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#if defined(LOCKDEBUG)
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#define lk_list lk_un.lk_un_spin.lk_spin_list
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#endif
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#if defined(LOCKDEBUG)
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const char *lk_lock_file;
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const char *lk_unlock_file;
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int lk_lock_line;
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int lk_unlock_line;
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#endif
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};
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/*
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* Lock request types:
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* LK_SHARED - get one of many possible shared locks. If a process
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* holding an exclusive lock requests a shared lock, the exclusive
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* lock(s) will be downgraded to shared locks.
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* LK_EXCLUSIVE - stop further shared locks, when they are cleared,
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* grant a pending upgrade if it exists, then grant an exclusive
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* lock. Only one exclusive lock may exist at a time, except that
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* a process holding an exclusive lock may get additional exclusive
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* locks if it explicitly sets the LK_CANRECURSE flag in the lock
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* request, or if the LK_CANRECUSE flag was set when the lock was
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* initialized.
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* LK_UPGRADE - the process must hold a shared lock that it wants to
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* have upgraded to an exclusive lock. Other processes may get
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* exclusive access to the resource between the time that the upgrade
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* is requested and the time that it is granted.
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* LK_EXCLUPGRADE - the process must hold a shared lock that it wants to
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* have upgraded to an exclusive lock. If the request succeeds, no
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* other processes will have gotten exclusive access to the resource
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* between the time that the upgrade is requested and the time that
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* it is granted. However, if another process has already requested
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* an upgrade, the request will fail (see error returns below).
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* LK_DOWNGRADE - the process must hold an exclusive lock that it wants
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* to have downgraded to a shared lock. If the process holds multiple
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* (recursive) exclusive locks, they will all be downgraded to shared
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* locks.
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* LK_RELEASE - release one instance of a lock.
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* LK_DRAIN - wait for all activity on the lock to end, then mark it
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* decommissioned. This feature is used before freeing a lock that
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* is part of a piece of memory that is about to be freed.
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*
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* These are flags that are passed to the lockmgr routine.
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*/
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#define LK_TYPE_MASK 0x0000000f /* type of lock sought */
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#define LK_SHARED 0x00000001 /* shared lock */
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#define LK_EXCLUSIVE 0x00000002 /* exclusive lock */
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#define LK_UPGRADE 0x00000003 /* shared-to-exclusive upgrade */
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#define LK_EXCLUPGRADE 0x00000004 /* first shared-to-exclusive upgrade */
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#define LK_DOWNGRADE 0x00000005 /* exclusive-to-shared downgrade */
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#define LK_RELEASE 0x00000006 /* release any type of lock */
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#define LK_DRAIN 0x00000007 /* wait for all lock activity to end */
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/*
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* External lock flags.
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*
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* The first three flags may be set in lock_init to set their mode permanently,
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* or passed in as arguments to the lock manager. The LK_REENABLE flag may be
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* set only at the release of a lock obtained by drain.
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*/
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#define LK_EXTFLG_MASK 0x00700070 /* mask of external flags */
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#define LK_NOWAIT 0x00000010 /* do not sleep to await lock */
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#define LK_SLEEPFAIL 0x00000020 /* sleep, then return failure */
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#define LK_CANRECURSE 0x00000040 /* this may be recursive lock attempt */
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#define LK_REENABLE 0x00000080 /* lock is be reenabled after drain */
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#define LK_SETRECURSE 0x00100000 /* other locks while we have it OK */
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#define LK_RECURSEFAIL 0x00200000 /* attempt at recursive lock fails */
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#define LK_SPIN 0x00400000 /* lock spins instead of sleeps */
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/*
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* Internal lock flags.
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*
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* These flags are used internally to the lock manager.
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*/
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#define LK_WANT_UPGRADE 0x00000100 /* waiting for share-to-excl upgrade */
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#define LK_WANT_EXCL 0x00000200 /* exclusive lock sought */
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#define LK_HAVE_EXCL 0x00000400 /* exclusive lock obtained */
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#define LK_WAITDRAIN 0x00000800 /* process waiting for lock to drain */
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#define LK_DRAINING 0x00004000 /* lock is being drained */
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#define LK_DRAINED 0x00008000 /* lock has been decommissioned */
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/*
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* Control flags
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*
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* Non-persistent external flags.
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*/
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#define LK_INTERLOCK 0x00010000 /* unlock passed simple lock after
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getting lk_interlock */
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#define LK_RETRY 0x00020000 /* vn_lock: retry until locked */
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/*
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* Lock return status.
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*
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* Successfully obtained locks return 0. Locks will always succeed
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* unless one of the following is true:
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* LK_FORCEUPGRADE is requested and some other process has already
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* requested a lock upgrade (returns EBUSY).
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* LK_WAIT is set and a sleep would be required (returns EBUSY).
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* LK_SLEEPFAIL is set and a sleep was done (returns ENOLCK).
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* PCATCH is set in lock priority and a signal arrives (returns
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* either EINTR or ERESTART if system calls is to be restarted).
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* Non-null lock timeout and timeout expires (returns EWOULDBLOCK).
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* A failed lock attempt always returns a non-zero error value. No lock
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* is held after an error return (in particular, a failed LK_UPGRADE
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* or LK_FORCEUPGRADE will have released its shared access lock).
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*/
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/*
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* Indicator that no process/cpu holds exclusive lock
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*/
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#define LK_KERNPROC ((pid_t) -2)
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#define LK_NOPROC ((pid_t) -1)
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#define LK_NOCPU ((cpuid_t) -1)
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#ifdef _KERNEL
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struct proc;
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void lockinit(struct lock *, int prio, const char *wmesg, int timo,
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int flags);
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#if defined(LOCKDEBUG)
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int _lockmgr(__volatile struct lock *, u_int flags, struct simplelock *,
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const char *file, int line);
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#define lockmgr(l, f, i) _lockmgr((l), (f), (i), __FILE__, __LINE__)
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#else
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int lockmgr(__volatile struct lock *, u_int flags, struct simplelock *);
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#endif /* LOCKDEBUG */
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int lockstatus(struct lock *);
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void lockmgr_printinfo(__volatile struct lock *);
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#if defined(LOCKDEBUG) || defined(DIAGNOSTIC)
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void spinlock_switchcheck(void);
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#endif
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#if defined(MULTIPROCESSOR) || defined(LOCKDEBUG)
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#define spinlockinit(lkp, name, flags) \
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lockinit((lkp), 0, (name), 0, (flags) | LK_SPIN)
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#define spinlockmgr(lkp, flags, intrlk) \
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lockmgr((lkp), (flags) | LK_SPIN, (intrlk))
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#else
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#define spinlockinit(lkp, name, flags) (void)(lkp)
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#define spinlockmgr(lkp, flags, intrlk) (0)
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#endif
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#if defined(LOCKDEBUG)
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int _spinlock_release_all(__volatile struct lock *, const char *, int);
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void _spinlock_acquire_count(__volatile struct lock *, int, const char *,
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int);
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#define spinlock_release_all(l) _spinlock_release_all((l), __FILE__, __LINE__)
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#define spinlock_acquire_count(l, c) _spinlock_acquire_count((l), (c), \
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__FILE__, __LINE__)
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#else
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int spinlock_release_all(__volatile struct lock *);
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void spinlock_acquire_count(__volatile struct lock *, int);
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#endif
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#if defined(LOCKDEBUG)
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void _simple_lock(__volatile struct simplelock *, const char *, int);
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int _simple_lock_try(__volatile struct simplelock *, const char *, int);
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void _simple_unlock(__volatile struct simplelock *, const char *, int);
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int _simple_lock_held(__volatile struct simplelock *);
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#define simple_lock(alp) _simple_lock((alp), __FILE__, __LINE__)
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#define simple_lock_try(alp) _simple_lock_try((alp), __FILE__, __LINE__)
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#define simple_unlock(alp) _simple_unlock((alp), __FILE__, __LINE__)
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#define simple_lock_held(alp) _simple_lock_held((alp))
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#define LOCK_ASSERT(x) KASSERT(x)
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void simple_lock_init(struct simplelock *);
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void simple_lock_dump(void);
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void simple_lock_freecheck(void *, void *);
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void simple_lock_switchcheck(void);
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#elif defined(MULTIPROCESSOR)
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#define simple_lock_init(alp) __cpu_simple_lock_init(&(alp)->lock_data)
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#define simple_lock(alp) __cpu_simple_lock(&(alp)->lock_data)
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#define simple_lock_try(alp) __cpu_simple_lock_try(&(alp)->lock_data)
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#define simple_unlock(alp) __cpu_simple_unlock(&(alp)->lock_data)
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#define LOCK_ASSERT(x) /* nothing */
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#else
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#define simple_lock_init(alp) (alp)->lock_data = __SIMPLELOCK_UNLOCKED
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#define simple_lock(alp) (void)(alp)
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#define simple_lock_try(alp) (1)
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#define simple_unlock(alp) (void)(alp)
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#define LOCK_ASSERT(x) /* nothing */
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#endif
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#endif /* _KERNEL */
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#endif /* _SYS_LOCK_H_ */
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