2 * atomic32.c: 32-bit atomic_t implementation
4 * Copyright (C) 2004 Keith M Wesolowski
5 * Copyright (C) 2007 Kyle McMartin
7 * Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf
10 #include <linux/atomic.h>
11 #include <linux/spinlock.h>
12 #include <linux/module.h>
15 #define ATOMIC_HASH_SIZE 4
16 #define ATOMIC_HASH(a) (&__atomic_hash[(((unsigned long)a)>>8) & (ATOMIC_HASH_SIZE-1)])
18 spinlock_t __atomic_hash
[ATOMIC_HASH_SIZE
] = {
19 [0 ... (ATOMIC_HASH_SIZE
-1)] = __SPIN_LOCK_UNLOCKED(__atomic_hash
)
24 static DEFINE_SPINLOCK(dummy
);
25 #define ATOMIC_HASH_SIZE 1
26 #define ATOMIC_HASH(a) (&dummy)
30 int __atomic_add_return(int i
, atomic_t
*v
)
34 spin_lock_irqsave(ATOMIC_HASH(v
), flags
);
36 ret
= (v
->counter
+= i
);
38 spin_unlock_irqrestore(ATOMIC_HASH(v
), flags
);
41 EXPORT_SYMBOL(__atomic_add_return
);
43 int atomic_cmpxchg(atomic_t
*v
, int old
, int new)
48 spin_lock_irqsave(ATOMIC_HASH(v
), flags
);
50 if (likely(ret
== old
))
53 spin_unlock_irqrestore(ATOMIC_HASH(v
), flags
);
56 EXPORT_SYMBOL(atomic_cmpxchg
);
58 int __atomic_add_unless(atomic_t
*v
, int a
, int u
)
63 spin_lock_irqsave(ATOMIC_HASH(v
), flags
);
67 spin_unlock_irqrestore(ATOMIC_HASH(v
), flags
);
70 EXPORT_SYMBOL(__atomic_add_unless
);
72 /* Atomic operations are already serializing */
73 void atomic_set(atomic_t
*v
, int i
)
77 spin_lock_irqsave(ATOMIC_HASH(v
), flags
);
79 spin_unlock_irqrestore(ATOMIC_HASH(v
), flags
);
81 EXPORT_SYMBOL(atomic_set
);
83 unsigned long ___set_bit(unsigned long *addr
, unsigned long mask
)
85 unsigned long old
, flags
;
87 spin_lock_irqsave(ATOMIC_HASH(addr
), flags
);
90 spin_unlock_irqrestore(ATOMIC_HASH(addr
), flags
);
94 EXPORT_SYMBOL(___set_bit
);
96 unsigned long ___clear_bit(unsigned long *addr
, unsigned long mask
)
98 unsigned long old
, flags
;
100 spin_lock_irqsave(ATOMIC_HASH(addr
), flags
);
103 spin_unlock_irqrestore(ATOMIC_HASH(addr
), flags
);
107 EXPORT_SYMBOL(___clear_bit
);
109 unsigned long ___change_bit(unsigned long *addr
, unsigned long mask
)
111 unsigned long old
, flags
;
113 spin_lock_irqsave(ATOMIC_HASH(addr
), flags
);
116 spin_unlock_irqrestore(ATOMIC_HASH(addr
), flags
);
120 EXPORT_SYMBOL(___change_bit
);
122 unsigned long __cmpxchg_u32(volatile u32
*ptr
, u32 old
, u32
new)
127 spin_lock_irqsave(ATOMIC_HASH(ptr
), flags
);
128 if ((prev
= *ptr
) == old
)
130 spin_unlock_irqrestore(ATOMIC_HASH(ptr
), flags
);
132 return (unsigned long)prev
;
134 EXPORT_SYMBOL(__cmpxchg_u32
);
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