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6e8b8726ad
True, it's often used in return statements, but after much bikeshedding it's probably better to have an explicit name. (I tried just putting the IS_ERR check inside PTR_ERR itself and gcc usually generated no more code. But that clashes current expectations of how PTR_ERR behaves, so having a separate function is better). Suggested-by: Julia Lawall <julia.lawall@lip6.fr> Suggested-by: "Michael S. Tsirkin" <mst@redhat.com> Cc: Julia Lawall <julia.lawall@lip6.fr> Cc: "Michael S. Tsirkin" <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
69 lines
1.5 KiB
C
69 lines
1.5 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 * __must_check 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 __must_check PTR_ERR(__force 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 __must_check IS_ERR(__force 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 __must_check IS_ERR_OR_NULL(__force 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 * __must_check ERR_CAST(__force 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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static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
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{
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if (IS_ERR(ptr))
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return PTR_ERR(ptr);
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else
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return 0;
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}
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/* Deprecated */
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#define PTR_RET(p) PTR_ERR_OR_ZERO(p)
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#endif
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#endif /* _LINUX_ERR_H */
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