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