cmpxchg-local.h
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#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
#define __ASM_GENERIC_CMPXCHG_LOCAL_H
#include <linux/types.h>
#include <linux/irqflags.h>
extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
/*
* Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
* long parameter, supporting various types of architectures.
*/
static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
unsigned long old, unsigned long new, int size)
{
unsigned long flags, prev;
/*
* Sanity checking, compile-time.
*/
if (size == 8 && sizeof(unsigned long) != 8)
wrong_size_cmpxchg(ptr);
raw_local_irq_save(flags);
switch (size) {
case 1: prev = *(u8 *)ptr;
if (prev == old)
*(u8 *)ptr = (u8)new;
break;
case 2: prev = *(u16 *)ptr;
if (prev == old)
*(u16 *)ptr = (u16)new;
break;
case 4: prev = *(u32 *)ptr;
if (prev == old)
*(u32 *)ptr = (u32)new;
break;
case 8: prev = *(u64 *)ptr;
if (prev == old)
*(u64 *)ptr = (u64)new;
break;
default:
wrong_size_cmpxchg(ptr);
}
raw_local_irq_restore(flags);
return prev;
}
/*
* Generic version of __cmpxchg64_local. Takes an u64 parameter.
*/
static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
u64 old, u64 new)
{
u64 prev;
unsigned long flags;
raw_local_irq_save(flags);
prev = *(u64 *)ptr;
if (prev == old)
*(u64 *)ptr = new;
raw_local_irq_restore(flags);
return prev;
}
#endif