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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [include/] [asm-ppc64/] [rwsem.h] - Blame information for rev 1275

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/*
 * include/asm-ppc/rwsem.h: R/W semaphores for PPC using the stuff
 * in lib/rwsem.c.  Adapted largely from include/asm-i386/rwsem.h
 * by Paul Mackerras <paulus@samba.org>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
 
#ifndef _PPC64_RWSEM_H
#define _PPC64_RWSEM_H
 
#ifdef __KERNEL__
#include <linux/list.h>
#include <linux/spinlock.h>
#include <asm/atomic.h>
#include <asm/system.h>
 
/*
 * the semaphore definition
 */
struct rw_semaphore {
        /* XXX this should be able to be an atomic_t  -- paulus */
        signed int              count;
#define RWSEM_UNLOCKED_VALUE            0x00000000
#define RWSEM_ACTIVE_BIAS               0x00000001
#define RWSEM_ACTIVE_MASK               0x0000ffff
#define RWSEM_WAITING_BIAS              (-0x00010000)
#define RWSEM_ACTIVE_READ_BIAS          RWSEM_ACTIVE_BIAS
#define RWSEM_ACTIVE_WRITE_BIAS         (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
        spinlock_t              wait_lock;
        struct list_head        wait_list;
#if RWSEM_DEBUG
        int                     debug;
#endif
};
 
/*
 * initialisation
 */
#if RWSEM_DEBUG
#define __RWSEM_DEBUG_INIT      , 0
#else
#define __RWSEM_DEBUG_INIT      /* */
#endif
 
#define __RWSEM_INITIALIZER(name) \
        { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
          LIST_HEAD_INIT((name).wait_list) \
          __RWSEM_DEBUG_INIT }
 
#define DECLARE_RWSEM(name)             \
        struct rw_semaphore name = __RWSEM_INITIALIZER(name)
 
extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
 
static inline void init_rwsem(struct rw_semaphore *sem)
{
        sem->count = RWSEM_UNLOCKED_VALUE;
        spin_lock_init(&sem->wait_lock);
        INIT_LIST_HEAD(&sem->wait_list);
#if RWSEM_DEBUG
        sem->debug = 0;
#endif
}
 
/*
 * lock for reading
 */
static inline void __down_read(struct rw_semaphore *sem)
{
        if (atomic_inc_return((atomic_t *)(&sem->count)) >= 0)
                smp_wmb();
        else
                rwsem_down_read_failed(sem);
}
 
static inline int __down_read_trylock(struct rw_semaphore *sem)
{
        int tmp;
 
        while ((tmp = sem->count) >= 0) {
                if (tmp == cmpxchg(&sem->count, tmp,
                                   tmp + RWSEM_ACTIVE_READ_BIAS)) {
                        smp_wmb();
                        return 1;
                }
        }
        return 0;
}
 
/*
 * lock for writing
 */
static inline void __down_write(struct rw_semaphore *sem)
{
        int tmp;
 
        tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
                                (atomic_t *)(&sem->count));
        if (tmp == RWSEM_ACTIVE_WRITE_BIAS)
                smp_wmb();
        else
                rwsem_down_write_failed(sem);
}
 
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
        int tmp;
 
        tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
                      RWSEM_ACTIVE_WRITE_BIAS);
        smp_wmb();
        return tmp == RWSEM_UNLOCKED_VALUE;
}
 
/*
 * unlock after reading
 */
static inline void __up_read(struct rw_semaphore *sem)
{
        int tmp;
 
        smp_wmb();
        tmp = atomic_dec_return((atomic_t *)(&sem->count));
        if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)
                rwsem_wake(sem);
}
 
/*
 * unlock after writing
 */
static inline void __up_write(struct rw_semaphore *sem)
{
        smp_wmb();
        if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,
                              (atomic_t *)(&sem->count)) < 0)
                rwsem_wake(sem);
}
 
/*
 * implement atomic add functionality
 */
static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
{
        atomic_add(delta, (atomic_t *)(&sem->count));
}
 
/*
 * implement exchange and add functionality
 */
static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
{
        smp_mb();
        return atomic_add_return(delta, (atomic_t *)(&sem->count));
}
 
#endif /* __KERNEL__ */
#endif /* _PPC_RWSEM_XADD_H */

Line No.	Rev	Author	Line
1	1275	phoenix	`/*`
2			`* include/asm-ppc/rwsem.h: R/W semaphores for PPC using the stuff`
3			`* in lib/rwsem.c. Adapted largely from include/asm-i386/rwsem.h`
4			`* by Paul Mackerras <paulus@samba.org>.`
5			`*`
6			`* This program is free software; you can redistribute it and/or`
7			`* modify it under the terms of the GNU General Public License`
8			`* as published by the Free Software Foundation; either version`
9			`* 2 of the License, or (at your option) any later version.`
10			`*/`
11
12			`#ifndef _PPC64_RWSEM_H`
13			`#define _PPC64_RWSEM_H`
14
15			`#ifdef __KERNEL__`
16			`#include <linux/list.h>`
17			`#include <linux/spinlock.h>`
18			`#include <asm/atomic.h>`
19			`#include <asm/system.h>`
20
21			`/*`
22			`* the semaphore definition`
23			`*/`
24			`struct rw_semaphore {`
25			`/* XXX this should be able to be an atomic_t -- paulus */`
26			`signed int count;`
27			`#define RWSEM_UNLOCKED_VALUE 0x00000000`
28			`#define RWSEM_ACTIVE_BIAS 0x00000001`
29			`#define RWSEM_ACTIVE_MASK 0x0000ffff`
30			`#define RWSEM_WAITING_BIAS (-0x00010000)`
31			`#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS`
32			`#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)`
33			`spinlock_t wait_lock;`
34			`struct list_head wait_list;`
35			`#if RWSEM_DEBUG`
36			`int debug;`
37			`#endif`
38			`};`
39
40			`/*`
41			`* initialisation`
42			`*/`
43			`#if RWSEM_DEBUG`
44			`#define __RWSEM_DEBUG_INIT , 0`
45			`#else`
46			`#define __RWSEM_DEBUG_INIT /* */`
47			`#endif`
48
49			`#define __RWSEM_INITIALIZER(name) \`
50			`{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \`
51			`LIST_HEAD_INIT((name).wait_list) \`
52			`__RWSEM_DEBUG_INIT }`
53
54			`#define DECLARE_RWSEM(name) \`
55			`struct rw_semaphore name = __RWSEM_INITIALIZER(name)`
56
57			`extern struct rw_semaphore rwsem_down_read_failed(struct rw_semaphore sem);`
58			`extern struct rw_semaphore rwsem_down_write_failed(struct rw_semaphore sem);`
59			`extern struct rw_semaphore rwsem_wake(struct rw_semaphore sem);`
60
61			`static inline void init_rwsem(struct rw_semaphore *sem)`
62			`{`
63			`sem->count = RWSEM_UNLOCKED_VALUE;`
64			`spin_lock_init(&sem->wait_lock);`
65			`INIT_LIST_HEAD(&sem->wait_list);`
66			`#if RWSEM_DEBUG`
67			`sem->debug = 0;`
68			`#endif`
69			`}`
70
71			`/*`
72			`* lock for reading`
73			`*/`
74			`static inline void __down_read(struct rw_semaphore *sem)`
75			`{`
76			`if (atomic_inc_return((atomic_t *)(&sem->count)) >= 0)`
77			`smp_wmb();`
78			`else`
79			`rwsem_down_read_failed(sem);`
80			`}`
81
82			`static inline int __down_read_trylock(struct rw_semaphore *sem)`
83			`{`
84			`int tmp;`
85
86			`while ((tmp = sem->count) >= 0) {`
87			`if (tmp == cmpxchg(&sem->count, tmp,`
88			`tmp + RWSEM_ACTIVE_READ_BIAS)) {`
89			`smp_wmb();`
90			`return 1;`
91			`}`
92			`}`
93			`return 0;`
94			`}`
95
96			`/*`
97			`* lock for writing`
98			`*/`
99			`static inline void __down_write(struct rw_semaphore *sem)`
100			`{`
101			`int tmp;`
102
103			`tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,`
104			`(atomic_t *)(&sem->count));`
105			`if (tmp == RWSEM_ACTIVE_WRITE_BIAS)`
106			`smp_wmb();`
107			`else`
108			`rwsem_down_write_failed(sem);`
109			`}`
110
111			`static inline int __down_write_trylock(struct rw_semaphore *sem)`
112			`{`
113			`int tmp;`
114
115			`tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,`
116			`RWSEM_ACTIVE_WRITE_BIAS);`
117			`smp_wmb();`
118			`return tmp == RWSEM_UNLOCKED_VALUE;`
119			`}`
120
121			`/*`
122			`* unlock after reading`
123			`*/`
124			`static inline void __up_read(struct rw_semaphore *sem)`
125			`{`
126			`int tmp;`
127
128			`smp_wmb();`
129			`tmp = atomic_dec_return((atomic_t *)(&sem->count));`
130			`if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)`
131			`rwsem_wake(sem);`
132			`}`
133
134			`/*`
135			`* unlock after writing`
136			`*/`
137			`static inline void __up_write(struct rw_semaphore *sem)`
138			`{`
139			`smp_wmb();`
140			`if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,`
141			`(atomic_t *)(&sem->count)) < 0)`
142			`rwsem_wake(sem);`
143			`}`
144
145			`/*`
146			`* implement atomic add functionality`
147			`*/`
148			`static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)`
149			`{`
150			`atomic_add(delta, (atomic_t *)(&sem->count));`
151			`}`
152
153			`/*`
154			`* implement exchange and add functionality`
155			`*/`
156			`static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)`
157			`{`
158			`smp_mb();`
159			`return atomic_add_return(delta, (atomic_t *)(&sem->count));`
160			`}`
161
162			`#endif /* __KERNEL__ */`
163			`#endif /* _PPC_RWSEM_XADD_H */`

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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [include/] [asm-ppc64/] [rwsem.h] - Blame information for rev 1275