xref: /xnu-11215/iokit/Kernel/IOLocks.cpp (revision 8149afcc)
1 /*
2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
3  *
4  * @APPLE_LICENSE_HEADER_START@
5  *
6  * The contents of this file constitute Original Code as defined in and
7  * are subject to the Apple Public Source License Version 1.1 (the
8  * "License").  You may not use this file except in compliance with the
9  * License.  Please obtain a copy of the License at
10  * http://www.apple.com/publicsource and read it before using this file.
11  *
12  * This Original Code and all software distributed under the License are
13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
17  * License for the specific language governing rights and limitations
18  * under the License.
19  *
20  * @APPLE_LICENSE_HEADER_END@
21  */
22 /*
23  * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
24  *
25  * HISTORY
26  *
27  */
28 
29 
30 #include <IOKit/system.h>
31 
32 #include <IOKit/IOReturn.h>
33 #include <IOKit/IOLib.h>
34 #include <IOKit/assert.h>
35 
36 extern "C" {
37 #include <kern/simple_lock.h>
38 #include <machine/machine_routines.h>
39 
40 IOLock * IOLockAlloc( void )
41 {
42     return( mutex_alloc(ETAP_IO_AHA) );
43 }
44 
45 void	IOLockFree( IOLock * lock)
46 {
47     mutex_free( lock );
48 }
49 
50 void	IOLockInitWithState( IOLock * lock, IOLockState state)
51 {
52     if( state == kIOLockStateLocked)
53         IOLockLock( lock);
54 }
55 
56 struct _IORecursiveLock {
57     mutex_t  *	mutex;
58     thread_t	thread;
59     UInt32	count;
60 };
61 
62 IORecursiveLock * IORecursiveLockAlloc( void )
63 {
64     _IORecursiveLock * lock;
65 
66     lock = IONew( _IORecursiveLock, 1);
67     if( !lock)
68         return( 0 );
69 
70     lock->mutex = mutex_alloc(ETAP_IO_AHA);
71     if( lock->mutex) {
72         lock->thread = 0;
73         lock->count  = 0;
74     } else {
75         IODelete( lock, _IORecursiveLock, 1);
76         lock = 0;
77     }
78 
79     return( (IORecursiveLock *) lock );
80 }
81 
82 void IORecursiveLockFree( IORecursiveLock * _lock )
83 {
84     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
85 
86     mutex_free( lock->mutex );
87     IODelete( lock, _IORecursiveLock, 1);
88 }
89 
90 void IORecursiveLockLock( IORecursiveLock * _lock)
91 {
92     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
93 
94     if( lock->thread == IOThreadSelf())
95         lock->count++;
96     else {
97         mutex_lock( lock->mutex );
98         assert( lock->thread == 0 );
99         assert( lock->count == 0 );
100         lock->thread = IOThreadSelf();
101         lock->count = 1;
102     }
103 }
104 
105 boolean_t IORecursiveLockTryLock( IORecursiveLock * _lock)
106 {
107     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
108 
109     if( lock->thread == IOThreadSelf()) {
110         lock->count++;
111 	return( true );
112     } else {
113         if( mutex_try( lock->mutex )) {
114             assert( lock->thread == 0 );
115             assert( lock->count == 0 );
116             lock->thread = IOThreadSelf();
117             lock->count = 1;
118             return( true );
119 	}
120     }
121     return( false );
122 }
123 
124 void IORecursiveLockUnlock( IORecursiveLock * _lock)
125 {
126     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
127 
128     assert( lock->thread == IOThreadSelf() );
129 
130     if( 0 == (--lock->count)) {
131         lock->thread = 0;
132         mutex_unlock( lock->mutex );
133     }
134 }
135 
136 boolean_t IORecursiveLockHaveLock( const IORecursiveLock * _lock)
137 {
138     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
139 
140     return( lock->thread == IOThreadSelf());
141 }
142 
143 int IORecursiveLockSleep(IORecursiveLock *_lock, void *event, UInt32 interType)
144 {
145     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
146     UInt32 count = lock->count;
147     int res;
148 
149     assert(lock->thread == IOThreadSelf());
150     assert(lock->count == 1 || interType == THREAD_UNINT);
151 
152     assert_wait((event_t) event, (int) interType);
153     lock->count = 0;
154     lock->thread = 0;
155     mutex_unlock(lock->mutex);
156 
157     res = thread_block(0);
158 
159     if (THREAD_AWAKENED == res) {
160         mutex_lock(lock->mutex);
161         assert(lock->thread == 0);
162         assert(lock->count == 0);
163         lock->thread = IOThreadSelf();
164         lock->count = count;
165     }
166 
167     return res;
168 }
169 
170 void IORecursiveLockWakeup(IORecursiveLock *, void *event, bool oneThread)
171 {
172     thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
173 }
174 
175 /*
176  * Complex (read/write) lock operations
177  */
178 
179 IORWLock * IORWLockAlloc( void )
180 {
181     IORWLock * lock;
182 
183     lock = lock_alloc( true, ETAP_IO_AHA, ETAP_IO_AHA);
184 
185     return( lock);
186 }
187 
188 void	IORWLockFree( IORWLock * lock)
189 {
190     lock_free( lock );
191 }
192 
193 
194 /*
195  * Spin locks
196  */
197 
198 IOSimpleLock * IOSimpleLockAlloc( void )
199 {
200     IOSimpleLock *	lock;
201 
202     lock = (IOSimpleLock *) IOMalloc( sizeof(IOSimpleLock));
203     if( lock)
204 	IOSimpleLockInit( lock );
205 
206     return( lock );
207 }
208 
209 void IOSimpleLockInit( IOSimpleLock * lock)
210 {
211     simple_lock_init( (simple_lock_t) lock, ETAP_IO_AHA );
212 }
213 
214 void IOSimpleLockFree( IOSimpleLock * lock )
215 {
216     IOFree( lock, sizeof(IOSimpleLock));
217 }
218 
219 } /* extern "C" */
220 
221 
222