1 /* PEAK Library
2 *
3 * Copyright (c) 2003
4 * Stephane Thiell <mbuna@bugged.org>. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
21 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 */
30 #define RCSID "$Id: task_lock.c,v 1.1.1.1 2003/12/30 02:29:31 mbuna Exp $"
31
32 #ifdef HAVE_CONFIG_H
33 #include "config.h"
34 #endif
35
36 #include <peak/task.h>
37
38 #include "task_private.h"
39
40 struct __peak_task_lock
41 {
42 PEAK_STRUCT_RT_HEADER;
43 peak_task _task; /* Owner task */
44 peak_spinlock_t _lock;
45 int _seq;
46 };
47
48 static void __peak_task_lock_init(peak_task_lock lock, va_list vp, void *ctcx);
49 static void __peak_task_lock_finalize(peak_task_lock lock);
50
51 PEAK_CLASS_BASE_DECLARE(task_lock);
52
53
54 peak_task_lock
peak_task_lock_create(peak_task task)55 peak_task_lock_create(peak_task task)
56 {
57 return PEAK_CLASS_CONSTRUCT1(task_lock, task);
58 }
59
60 static void
__peak_task_lock_init(peak_task_lock lock,va_list vp,void * ctcx)61 __peak_task_lock_init(peak_task_lock lock, va_list vp, void *ctcx)
62 {
63 lock->_task = va_arg(vp, peak_task);
64 lock->_lock = PEAK_SPINLOCK_INITIALIZER;
65 lock->_seq = 0; /* not important */
66 }
67
68 static void
__peak_task_lock_finalize(peak_task_lock lock)69 __peak_task_lock_finalize(peak_task_lock lock)
70 {
71 }
72
73 void
peak_task_lock_acquire(peak_task_lock lock)74 peak_task_lock_acquire(peak_task_lock lock)
75 {
76 _peak_spinlock_lock(&lock->_lock);
77 lock->_seq++;
78 }
79
80 int
peak_task_lock_try(peak_task_lock lock)81 peak_task_lock_try(peak_task_lock lock)
82 {
83 return _peak_spinlock_lock_try(&lock->_lock);
84 }
85
86 void
peak_task_lock_release(peak_task_lock lock)87 peak_task_lock_release(peak_task_lock lock)
88 {
89 _peak_spinlock_unlock(&lock->_lock);
90 }
91
92 /* /me fiddles with hand-off :p
93 */
94 void
peak_task_lock_handoff(peak_task_lock lock)95 peak_task_lock_handoff(peak_task_lock lock)
96 {
97 int seq = lock->_seq;
98
99 if (!_peak_is_threaded)
100 PEAK_HALT; /* You should have read the nice docs ! */
101
102 _peak_spinlock_unlock(&lock->_lock);
103
104 /* We want the lock to be acquired!
105 * We might loose some cycles there...
106 */
107 while (lock->_seq == seq)
108 ;
109 }
110