603c4ba96b
There are quite a few instances in the kernel of checks of pointers both against NULL and against the errno range, handling both cases identically. This additional helper function would simplify such code. [akpm@linux-foundation.org: build fix] Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
#ifndef _LINUX_ERR_H
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#define _LINUX_ERR_H
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#include <linux/compiler.h>
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#include <asm/errno.h>
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/*
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* Kernel pointers have redundant information, so we can use a
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* scheme where we can return either an error code or a dentry
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* pointer with the same return value.
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*
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* This should be a per-architecture thing, to allow different
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* error and pointer decisions.
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*/
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#define MAX_ERRNO 4095
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#ifndef __ASSEMBLY__
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#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
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static inline void *ERR_PTR(long error)
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{
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return (void *) error;
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}
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static inline long PTR_ERR(const void *ptr)
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{
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return (long) ptr;
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}
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static inline long IS_ERR(const void *ptr)
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{
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return IS_ERR_VALUE((unsigned long)ptr);
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}
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static inline long IS_ERR_OR_NULL(const void *ptr)
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{
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return !ptr || IS_ERR_VALUE((unsigned long)ptr);
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}
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/**
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* ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
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* @ptr: The pointer to cast.
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*
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* Explicitly cast an error-valued pointer to another pointer type in such a
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* way as to make it clear that's what's going on.
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*/
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static inline void *ERR_CAST(const void *ptr)
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{
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/* cast away the const */
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return (void *) ptr;
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}
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#endif
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#endif /* _LINUX_ERR_H */
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