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Fix uninitialized return code in default case in cmpxchg-local.h This patch fixes the code to prevent an uninitialized return value that is detected when compiling with clang. The bug produces numerous warnings when compiling the Linux kernel with clang. Signed-off-by: Behan Webster <behanw@converseincode.com> Signed-off-by: Mark Charlebois <charlebm@gmail.com> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
68 lines
1.4 KiB
C
68 lines
1.4 KiB
C
#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
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#define __ASM_GENERIC_CMPXCHG_LOCAL_H
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#include <linux/types.h>
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#include <linux/irqflags.h>
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extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
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__noreturn;
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/*
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* Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
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* long parameter, supporting various types of architectures.
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*/
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static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
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unsigned long old, unsigned long new, int size)
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{
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unsigned long flags, prev;
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/*
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* Sanity checking, compile-time.
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*/
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if (size == 8 && sizeof(unsigned long) != 8)
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wrong_size_cmpxchg(ptr);
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raw_local_irq_save(flags);
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switch (size) {
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case 1: prev = *(u8 *)ptr;
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if (prev == old)
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*(u8 *)ptr = (u8)new;
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break;
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case 2: prev = *(u16 *)ptr;
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if (prev == old)
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*(u16 *)ptr = (u16)new;
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break;
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case 4: prev = *(u32 *)ptr;
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if (prev == old)
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*(u32 *)ptr = (u32)new;
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break;
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case 8: prev = *(u64 *)ptr;
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if (prev == old)
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*(u64 *)ptr = (u64)new;
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break;
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default:
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wrong_size_cmpxchg(ptr);
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}
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raw_local_irq_restore(flags);
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return prev;
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}
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/*
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* Generic version of __cmpxchg64_local. Takes an u64 parameter.
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*/
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static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
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u64 old, u64 new)
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{
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u64 prev;
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unsigned long flags;
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raw_local_irq_save(flags);
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prev = *(u64 *)ptr;
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if (prev == old)
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*(u64 *)ptr = new;
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raw_local_irq_restore(flags);
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return prev;
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}
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#endif
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