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include/asm-generic/cmpxchg-local.h
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#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H #define __ASM_GENERIC_CMPXCHG_LOCAL_H #include <linux/types.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); 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); } 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; local_irq_save(flags); prev = *(u64 *)ptr; if (prev == old) *(u64 *)ptr = new; local_irq_restore(flags); return prev; } #endif |