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 24 static inline void *ERR_PTR(long error) 25 { 26 return (void *) error; 27 } 28 29 static inline long PTR_ERR(const void *ptr) 30 { 31 return (long) ptr; 32 } 33 34 static inline long IS_ERR(const void *ptr) 35 { 36 return IS_ERR_VALUE((unsigned long)ptr); 37 } 38 39 /** 40 * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type 41 * @ptr: The pointer to cast. 42 * 43 * Explicitly cast an error-valued pointer to another pointer type in such a 44 * way as to make it clear that's what's going on. 45 */ 46 static inline void * __must_check ERR_CAST(__force const void *ptr) 47 { 48 /* cast away the const */ 49 return (void *) ptr; 50 } 51 52 #endif 53 54 #endif /* _LINUX_ERR_H */ 55