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