1#ifndef _LINUX_ERR_H 2#define _LINUX_ERR_H 3 4#include <linux/compiler.h> 5 6#include <asm/errno.h> 7 8/* 9 * Kernel pointers have redundant information, so we can use a 10 * scheme where we can return either an error code or a dentry 11 * pointer with the same return value. 12 * 13 * This should be a per-architecture thing, to allow different 14 * error and pointer decisions. 15 */ 16#define MAX_ERRNO 4095 17 18#ifndef __ASSEMBLY__ 19 20#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) 21 22static inline void * __must_check ERR_PTR(long error) 23{ 24 return (void *) error; 25} 26 27static inline long __must_check PTR_ERR(__force const void *ptr) 28{ 29 return (long) ptr; 30} 31 32static inline long __must_check IS_ERR(__force const void *ptr) 33{ 34 return IS_ERR_VALUE((unsigned long)ptr); 35} 36 37static inline long __must_check IS_ERR_OR_NULL(__force const void *ptr) 38{ 39 return !ptr || IS_ERR_VALUE((unsigned long)ptr); 40} 41 42/** 43 * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type 44 * @ptr: The pointer to cast. 45 * 46 * Explicitly cast an error-valued pointer to another pointer type in such a 47 * way as to make it clear that's what's going on. 48 */ 49static inline void * __must_check ERR_CAST(__force const void *ptr) 50{ 51 /* cast away the const */ 52 return (void *) ptr; 53} 54 55static inline int __must_check PTR_RET(__force const void *ptr) 56{ 57 if (IS_ERR(ptr)) 58 return PTR_ERR(ptr); 59 else 60 return 0; 61} 62 63#endif 64 65#endif /* _LINUX_ERR_H */ 66