Do some fairly major include file cleanups to further separate kernelland
[dragonfly.git] / sys / sys / lock.h
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1/*
2 * Copyright (c) 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code contains ideas from software contributed to Berkeley by
6 * Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
7 * System project at Carnegie-Mellon University.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)lock.h 8.12 (Berkeley) 5/19/95
38 * $FreeBSD: src/sys/sys/lock.h,v 1.17.2.3 2001/12/25 01:44:44 dillon Exp $
05220613 39 * $DragonFly: src/sys/sys/lock.h,v 1.7 2003/11/21 22:46:13 dillon Exp $
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40 */
41
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42#ifndef _SYS_LOCK_H_
43#define _SYS_LOCK_H_
44
45/*
46 * A number of third party programs #include <sys/lock.h> for no good
47 * reason. Don't actually include anything unless we are the kernel.
48 */
49#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
984263bc 50
984263bc 51#include <machine/lock.h>
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52#ifndef _SYS_THREAD_H_
53#include <sys/thread.h> /* lwkt_token */
54#endif
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55
56/*
57 * The general lock structure. Provides for multiple shared locks,
58 * upgrading from shared to exclusive, and sleeping until the lock
8a8d5d85 59 * can be gained.
984263bc 60 */
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61struct thread;
62
984263bc 63struct lock {
8a8d5d85 64 lwkt_token lk_interlock; /* lock on remaining fields */
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65 u_int lk_flags; /* see below */
66 int lk_sharecount; /* # of accepted shared locks */
67 int lk_waitcount; /* # of processes sleeping for lock */
68 short lk_exclusivecount; /* # of recursive exclusive locks */
377d4740 69 short lk_prio; /* tsleep flags */
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70 char *lk_wmesg; /* resource sleeping (for tsleep) */
71 int lk_timo; /* maximum sleep time (for tsleep) */
dadab5e9 72 struct thread *lk_lockholder; /* thread of excl lock holder */
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73#ifdef DEBUG_LOCKS
74 const char *lk_filename;
75 const char *lk_lockername;
76 int lk_lineno;
77#endif
78};
79/*
80 * Lock request types:
81 * LK_SHARED - get one of many possible shared locks. If a process
82 * holding an exclusive lock requests a shared lock, the exclusive
83 * lock(s) will be downgraded to shared locks.
84 * LK_EXCLUSIVE - stop further shared locks, when they are cleared,
85 * grant a pending upgrade if it exists, then grant an exclusive
86 * lock. Only one exclusive lock may exist at a time, except that
87 * a process holding an exclusive lock may get additional exclusive
88 * locks if it explicitly sets the LK_CANRECURSE flag in the lock
89 * request, or if the LK_CANRECUSE flag was set when the lock was
90 * initialized.
91 * LK_UPGRADE - the process must hold a shared lock that it wants to
92 * have upgraded to an exclusive lock. Other processes may get
93 * exclusive access to the resource between the time that the upgrade
94 * is requested and the time that it is granted.
95 * LK_EXCLUPGRADE - the process must hold a shared lock that it wants to
96 * have upgraded to an exclusive lock. If the request succeeds, no
97 * other processes will have gotten exclusive access to the resource
98 * between the time that the upgrade is requested and the time that
99 * it is granted. However, if another process has already requested
100 * an upgrade, the request will fail (see error returns below).
101 * LK_DOWNGRADE - the process must hold an exclusive lock that it wants
102 * to have downgraded to a shared lock. If the process holds multiple
103 * (recursive) exclusive locks, they will all be downgraded to shared
104 * locks.
105 * LK_RELEASE - release one instance of a lock.
106 * LK_DRAIN - wait for all activity on the lock to end, then mark it
107 * decommissioned. This feature is used before freeing a lock that
108 * is part of a piece of memory that is about to be freed.
109 * LK_EXCLOTHER - return for lockstatus(). Used when another process
110 * holds the lock exclusively.
111 *
112 * These are flags that are passed to the lockmgr routine.
113 */
114#define LK_TYPE_MASK 0x0000000f /* type of lock sought */
115#define LK_SHARED 0x00000001 /* shared lock */
116#define LK_EXCLUSIVE 0x00000002 /* exclusive lock */
117#define LK_UPGRADE 0x00000003 /* shared-to-exclusive upgrade */
118#define LK_EXCLUPGRADE 0x00000004 /* first shared-to-exclusive upgrade */
119#define LK_DOWNGRADE 0x00000005 /* exclusive-to-shared downgrade */
120#define LK_RELEASE 0x00000006 /* release any type of lock */
121#define LK_DRAIN 0x00000007 /* wait for all lock activity to end */
122#define LK_EXCLOTHER 0x00000008 /* other process holds lock */
123/*
124 * External lock flags.
125 *
126 * The first three flags may be set in lock_init to set their mode permanently,
127 * or passed in as arguments to the lock manager. The LK_REENABLE flag may be
128 * set only at the release of a lock obtained by drain.
129 */
130#define LK_EXTFLG_MASK 0x03000070 /* mask of external flags */
131#define LK_NOWAIT 0x00000010 /* do not sleep to await lock */
132#define LK_SLEEPFAIL 0x00000020 /* sleep, then return failure */
133#define LK_CANRECURSE 0x00000040 /* allow recursive exclusive lock */
134#define LK_REENABLE 0x00000080 /* lock is be reenabled after drain */
135#define LK_NOPAUSE 0x01000000 /* no spinloop */
136#define LK_TIMELOCK 0x02000000
137/*
138 * Internal lock flags.
139 *
140 * These flags are used internally to the lock manager.
141 */
142#define LK_WANT_UPGRADE 0x00000100 /* waiting for share-to-excl upgrade */
143#define LK_WANT_EXCL 0x00000200 /* exclusive lock sought */
144#define LK_HAVE_EXCL 0x00000400 /* exclusive lock obtained */
145#define LK_WAITDRAIN 0x00000800 /* process waiting for lock to drain */
146#define LK_DRAINING 0x00004000 /* lock is being drained */
147/*
148 * Control flags
149 *
150 * Non-persistent external flags.
151 */
152#define LK_INTERLOCK 0x00010000 /* unlock passed simple lock after
153 getting lk_interlock */
154#define LK_RETRY 0x00020000 /* vn_lock: retry until locked */
155#define LK_NOOBJ 0x00040000 /* vget: don't create object */
156#define LK_THISLAYER 0x00080000 /* vn_lock: lock/unlock only current layer */
157
158/*
159 * Internal state flags corresponding to lk_sharecount, and lk_waitcount
160 */
161#define LK_SHARE_NONZERO 0x00100000
162#define LK_WAIT_NONZERO 0x00200000
163
164/*
165 * Lock return status.
166 *
167 * Successfully obtained locks return 0. Locks will always succeed
168 * unless one of the following is true:
169 * LK_FORCEUPGRADE is requested and some other process has already
170 * requested a lock upgrade (returns EBUSY).
171 * LK_WAIT is set and a sleep would be required (returns EBUSY).
172 * LK_SLEEPFAIL is set and a sleep was done (returns ENOLCK).
173 * PCATCH is set in lock priority and a signal arrives (returns
174 * either EINTR or ERESTART if system calls is to be restarted).
175 * Non-null lock timeout and timeout expires (returns EWOULDBLOCK).
176 * A failed lock attempt always returns a non-zero error value. No lock
177 * is held after an error return (in particular, a failed LK_UPGRADE
178 * or LK_FORCEUPGRADE will have released its shared access lock).
179 */
180
181/*
182 * Indicator that no process holds exclusive lock
183 */
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184#define LK_KERNTHREAD ((struct thread *)-2)
185#define LK_NOTHREAD ((struct thread *)-1)
984263bc 186
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187#ifdef _KERNEL
188
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189void dumplockinfo(struct lock *lkp);
190struct proc;
191
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192void lockinit (struct lock *, int prio, char *wmesg, int timo,
193 int flags);
984263bc 194#ifdef DEBUG_LOCKS
b153f746 195int debuglockmgr (struct lock *, u_int flags,
8a8d5d85 196 struct lwkt_token *, struct thread *p,
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197 const char *,
198 const char *,
b153f746 199 int);
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200#define lockmgr(lockp, flags, slockp, td) \
201 debuglockmgr((lockp), (flags), (slockp), (td), \
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202 "lockmgr", __FILE__, __LINE__)
203#else
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204int lockmgr (struct lock *, u_int flags,
205 struct lwkt_token *, struct thread *td);
984263bc 206#endif
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207void lockmgr_printinfo (struct lock *);
208int lockstatus (struct lock *, struct thread *);
209int lockcount (struct lock *);
984263bc 210
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211#endif /* _KERNEL */
212#endif /* _KERNEL || _KERNEL_STRUCTURES */
213#endif /* _SYS_LOCK_H_ */
214