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-rw-r--r--arch/m32r/kernel/semaphore.c185
1 files changed, 0 insertions, 185 deletions
diff --git a/arch/m32r/kernel/semaphore.c b/arch/m32r/kernel/semaphore.c
deleted file mode 100644
index 940c2d37cfd1..000000000000
--- a/arch/m32r/kernel/semaphore.c
+++ /dev/null
@@ -1,185 +0,0 @@
1/*
2 * linux/arch/m32r/semaphore.c
3 * orig : i386 2.6.4
4 *
5 * M32R semaphore implementation.
6 *
7 * Copyright (c) 2002 - 2004 Hitoshi Yamamoto
8 */
9
10/*
11 * i386 semaphore implementation.
12 *
13 * (C) Copyright 1999 Linus Torvalds
14 *
15 * Portions Copyright 1999 Red Hat, Inc.
16 *
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version
20 * 2 of the License, or (at your option) any later version.
21 *
22 * rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
23 */
24#include <linux/sched.h>
25#include <linux/err.h>
26#include <linux/init.h>
27#include <asm/semaphore.h>
28
29/*
30 * Semaphores are implemented using a two-way counter:
31 * The "count" variable is decremented for each process
32 * that tries to acquire the semaphore, while the "sleeping"
33 * variable is a count of such acquires.
34 *
35 * Notably, the inline "up()" and "down()" functions can
36 * efficiently test if they need to do any extra work (up
37 * needs to do something only if count was negative before
38 * the increment operation.
39 *
40 * "sleeping" and the contention routine ordering is protected
41 * by the spinlock in the semaphore's waitqueue head.
42 *
43 * Note that these functions are only called when there is
44 * contention on the lock, and as such all this is the
45 * "non-critical" part of the whole semaphore business. The
46 * critical part is the inline stuff in <asm/semaphore.h>
47 * where we want to avoid any extra jumps and calls.
48 */
49
50/*
51 * Logic:
52 * - only on a boundary condition do we need to care. When we go
53 * from a negative count to a non-negative, we wake people up.
54 * - when we go from a non-negative count to a negative do we
55 * (a) synchronize with the "sleeper" count and (b) make sure
56 * that we're on the wakeup list before we synchronize so that
57 * we cannot lose wakeup events.
58 */
59
60asmlinkage void __up(struct semaphore *sem)
61{
62 wake_up(&sem->wait);
63}
64
65asmlinkage void __sched __down(struct semaphore * sem)
66{
67 struct task_struct *tsk = current;
68 DECLARE_WAITQUEUE(wait, tsk);
69 unsigned long flags;
70
71 tsk->state = TASK_UNINTERRUPTIBLE;
72 spin_lock_irqsave(&sem->wait.lock, flags);
73 add_wait_queue_exclusive_locked(&sem->wait, &wait);
74
75 sem->sleepers++;
76 for (;;) {
77 int sleepers = sem->sleepers;
78
79 /*
80 * Add "everybody else" into it. They aren't
81 * playing, because we own the spinlock in
82 * the wait_queue_head.
83 */
84 if (!atomic_add_negative(sleepers - 1, &sem->count)) {
85 sem->sleepers = 0;
86 break;
87 }
88 sem->sleepers = 1; /* us - see -1 above */
89 spin_unlock_irqrestore(&sem->wait.lock, flags);
90
91 schedule();
92
93 spin_lock_irqsave(&sem->wait.lock, flags);
94 tsk->state = TASK_UNINTERRUPTIBLE;
95 }
96 remove_wait_queue_locked(&sem->wait, &wait);
97 wake_up_locked(&sem->wait);
98 spin_unlock_irqrestore(&sem->wait.lock, flags);
99 tsk->state = TASK_RUNNING;
100}
101
102asmlinkage int __sched __down_interruptible(struct semaphore * sem)
103{
104 int retval = 0;
105 struct task_struct *tsk = current;
106 DECLARE_WAITQUEUE(wait, tsk);
107 unsigned long flags;
108
109 tsk->state = TASK_INTERRUPTIBLE;
110 spin_lock_irqsave(&sem->wait.lock, flags);
111 add_wait_queue_exclusive_locked(&sem->wait, &wait);
112
113 sem->sleepers++;
114 for (;;) {
115 int sleepers = sem->sleepers;
116
117 /*
118 * With signals pending, this turns into
119 * the trylock failure case - we won't be
120 * sleeping, and we* can't get the lock as
121 * it has contention. Just correct the count
122 * and exit.
123 */
124 if (signal_pending(current)) {
125 retval = -EINTR;
126 sem->sleepers = 0;
127 atomic_add(sleepers, &sem->count);
128 break;
129 }
130
131 /*
132 * Add "everybody else" into it. They aren't
133 * playing, because we own the spinlock in
134 * wait_queue_head. The "-1" is because we're
135 * still hoping to get the semaphore.
136 */
137 if (!atomic_add_negative(sleepers - 1, &sem->count)) {
138 sem->sleepers = 0;
139 break;
140 }
141 sem->sleepers = 1; /* us - see -1 above */
142 spin_unlock_irqrestore(&sem->wait.lock, flags);
143
144 schedule();
145
146 spin_lock_irqsave(&sem->wait.lock, flags);
147 tsk->state = TASK_INTERRUPTIBLE;
148 }
149 remove_wait_queue_locked(&sem->wait, &wait);
150 wake_up_locked(&sem->wait);
151 spin_unlock_irqrestore(&sem->wait.lock, flags);
152
153 tsk->state = TASK_RUNNING;
154 return retval;
155}
156
157/*
158 * Trylock failed - make sure we correct for
159 * having decremented the count.
160 *
161 * We could have done the trylock with a
162 * single "cmpxchg" without failure cases,
163 * but then it wouldn't work on a 386.
164 */
165asmlinkage int __down_trylock(struct semaphore * sem)
166{
167 int sleepers;
168 unsigned long flags;
169
170 spin_lock_irqsave(&sem->wait.lock, flags);
171 sleepers = sem->sleepers + 1;
172 sem->sleepers = 0;
173
174 /*
175 * Add "everybody else" and us into it. They aren't
176 * playing, because we own the spinlock in the
177 * wait_queue_head.
178 */
179 if (!atomic_add_negative(sleepers, &sem->count)) {
180 wake_up_locked(&sem->wait);
181 }
182
183 spin_unlock_irqrestore(&sem->wait.lock, flags);
184 return 1;
185}
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