1 /* 2 * atomic32.c: 32-bit atomic_t implementation 3 * 4 * Copyright (C) 2004 Keith M Wesolowski 5 * 6 * Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf 7 */ 8 9 #include <asm/atomic.h> 10 #include <linux/spinlock.h> 11 #include <linux/module.h> 12 13 #ifdef CONFIG_SMP 14 #define ATOMIC_HASH_SIZE 4 15 #define ATOMIC_HASH(a) (&__atomic_hash[(((unsigned long)a)>>8) & (ATOMIC_HASH_SIZE-1)]) 16 17 spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = { 18 [0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED 19 }; 20 21 #else /* SMP */ 22 23 static DEFINE_SPINLOCK(dummy); 24 #define ATOMIC_HASH_SIZE 1 25 #define ATOMIC_HASH(a) (&dummy) 26 27 #endif /* SMP */ 28 29 int __atomic_add_return(int i, atomic_t *v) 30 { 31 int ret; 32 unsigned long flags; 33 spin_lock_irqsave(ATOMIC_HASH(v), flags); 34 35 ret = (v->counter += i); 36 37 spin_unlock_irqrestore(ATOMIC_HASH(v), flags); 38 return ret; 39 } 40 41 void atomic_set(atomic_t *v, int i) 42 { 43 unsigned long flags; 44 spin_lock_irqsave(ATOMIC_HASH(v), flags); 45 46 v->counter = i; 47 48 spin_unlock_irqrestore(ATOMIC_HASH(v), flags); 49 } 50 51 EXPORT_SYMBOL(__atomic_add_return); 52 EXPORT_SYMBOL(atomic_set); 53 54