kernel: add a flags argument to LOCK_SYSINIT
[dragonfly.git] / sys / sys / lock.h
CommitLineData
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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 $
8fc3c98f 39 * $DragonFly: src/sys/sys/lock.h,v 1.19 2007/08/20 05:44:58 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#ifndef _SYS_SPINLOCK_H_
56#include <sys/spinlock.h>
57#endif
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58
59/*
60 * The general lock structure. Provides for multiple shared locks,
61 * upgrading from shared to exclusive, and sleeping until the lock
8a8d5d85 62 * can be gained.
984263bc 63 */
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64struct thread;
65
984263bc 66struct lock {
16523a43 67 struct spinlock lk_spinlock; /* lock on remaining fields */
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68 u_int lk_flags; /* see below */
69 int lk_sharecount; /* # of accepted shared locks */
70 int lk_waitcount; /* # of processes sleeping for lock */
71 short lk_exclusivecount; /* # of recursive exclusive locks */
f2770c70 72 short lk_unused1;
29600e7c 73 const char *lk_wmesg; /* resource sleeping (for tsleep) */
984263bc 74 int lk_timo; /* maximum sleep time (for tsleep) */
dadab5e9 75 struct thread *lk_lockholder; /* thread of excl lock holder */
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76#ifdef DEBUG_LOCKS
77 const char *lk_filename;
78 const char *lk_lockername;
79 int lk_lineno;
80#endif
81};
82/*
83 * Lock request types:
84 * LK_SHARED - get one of many possible shared locks. If a process
85 * holding an exclusive lock requests a shared lock, the exclusive
86 * lock(s) will be downgraded to shared locks.
87 * LK_EXCLUSIVE - stop further shared locks, when they are cleared,
88 * grant a pending upgrade if it exists, then grant an exclusive
89 * lock. Only one exclusive lock may exist at a time, except that
90 * a process holding an exclusive lock may get additional exclusive
91 * locks if it explicitly sets the LK_CANRECURSE flag in the lock
92 * request, or if the LK_CANRECUSE flag was set when the lock was
93 * initialized.
94 * LK_UPGRADE - the process must hold a shared lock that it wants to
95 * have upgraded to an exclusive lock. Other processes may get
96 * exclusive access to the resource between the time that the upgrade
97 * is requested and the time that it is granted.
98 * LK_EXCLUPGRADE - the process must hold a shared lock that it wants to
99 * have upgraded to an exclusive lock. If the request succeeds, no
100 * other processes will have gotten exclusive access to the resource
101 * between the time that the upgrade is requested and the time that
102 * it is granted. However, if another process has already requested
103 * an upgrade, the request will fail (see error returns below).
104 * LK_DOWNGRADE - the process must hold an exclusive lock that it wants
105 * to have downgraded to a shared lock. If the process holds multiple
106 * (recursive) exclusive locks, they will all be downgraded to shared
107 * locks.
108 * LK_RELEASE - release one instance of a lock.
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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 */
ca2e1d01 121#define LK_UNUSED07 0x00000007
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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,
4a3ab83d 127 * or passed in as arguments to the lock manager.
984263bc 128 */
f2770c70 129#define LK_EXTFLG_MASK 0x07000070 /* mask of external flags */
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130#define LK_NOWAIT 0x00000010 /* do not sleep to await lock */
131#define LK_SLEEPFAIL 0x00000020 /* sleep, then return failure */
132#define LK_CANRECURSE 0x00000040 /* allow recursive exclusive lock */
4a3ab83d 133#define LK_UNUSED0080 0x00000080
b12defdc 134#define LK_UNUSED0100x 0x01000000
984263bc 135#define LK_TIMELOCK 0x02000000
f2770c70 136#define LK_PCATCH 0x04000000 /* timelocked with signal catching */
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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 */
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145#define LK_UNUSED0800 0x00000800
146#define LK_UNUSED4000 0x00004000
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147/*
148 * Control flags
149 *
150 * Non-persistent external flags.
151 */
056f4388 152#define LK_UNUSED10000 0x00010000
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153#define LK_RETRY 0x00020000 /* vn_lock: retry until locked */
154#define LK_NOOBJ 0x00040000 /* vget: don't create object */
155#define LK_THISLAYER 0x00080000 /* vn_lock: lock/unlock only current layer */
156
157/*
158 * Internal state flags corresponding to lk_sharecount, and lk_waitcount
159 */
160#define LK_SHARE_NONZERO 0x00100000
161#define LK_WAIT_NONZERO 0x00200000
162
163/*
164 * Lock return status.
165 *
166 * Successfully obtained locks return 0. Locks will always succeed
167 * unless one of the following is true:
168 * LK_FORCEUPGRADE is requested and some other process has already
169 * requested a lock upgrade (returns EBUSY).
170 * LK_WAIT is set and a sleep would be required (returns EBUSY).
171 * LK_SLEEPFAIL is set and a sleep was done (returns ENOLCK).
172 * PCATCH is set in lock priority and a signal arrives (returns
173 * either EINTR or ERESTART if system calls is to be restarted).
174 * Non-null lock timeout and timeout expires (returns EWOULDBLOCK).
175 * A failed lock attempt always returns a non-zero error value. No lock
176 * is held after an error return (in particular, a failed LK_UPGRADE
177 * or LK_FORCEUPGRADE will have released its shared access lock).
178 */
179
180/*
181 * Indicator that no process holds exclusive lock
182 */
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183#define LK_KERNTHREAD ((struct thread *)-2)
184#define LK_NOTHREAD ((struct thread *)-1)
984263bc 185
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186#ifdef _KERNEL
187
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188void dumplockinfo(struct lock *lkp);
189struct proc;
190
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191struct lock_args {
192 struct lock *la_lock;
193 const char *la_desc;
124eeca9 194 int la_flags;
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195};
196
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197void lockinit (struct lock *, const char *wmesg, int timo, int flags);
198void lockreinit (struct lock *, const char *wmesg, int timo, int flags);
8fc3c98f 199void lockuninit(struct lock *);
5d101ab9 200void lock_sysinit(struct lock_args *);
984263bc 201#ifdef DEBUG_LOCKS
b153f746 202int debuglockmgr (struct lock *, u_int flags,
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203 const char *,
204 const char *,
b153f746 205 int);
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206#define lockmgr(lockp, flags) \
207 debuglockmgr((lockp), (flags), "lockmgr", __FILE__, __LINE__)
984263bc 208#else
df4f70a6 209int lockmgr (struct lock *, u_int flags);
984263bc 210#endif
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211void lockmgr_setexclusive_interlocked(struct lock *);
212void lockmgr_clrexclusive_interlocked(struct lock *);
df4f70a6 213void lockmgr_kernproc (struct lock *);
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214void lockmgr_printinfo (struct lock *);
215int lockstatus (struct lock *, struct thread *);
43903f4c 216int lockowned (struct lock *);
b153f746 217int lockcount (struct lock *);
b265bae0 218int lockcountnb (struct lock *);
984263bc 219
124eeca9 220#define LOCK_SYSINIT(name, lock, desc, flags) \
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221 static struct lock_args name##_args = { \
222 (lock), \
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223 (desc), \
224 (flags) \
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225 }; \
226 SYSINIT(name##_lock_sysinit, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, \
227 lock_sysinit, &name##_args); \
228 SYSUNINIT(name##_lock_sysuninit, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, \
229 lockuninit, (lock))
230
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231#endif /* _KERNEL */
232#endif /* _KERNEL || _KERNEL_STRUCTURES */
233#endif /* _SYS_LOCK_H_ */