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 22 static inline void * __must_check ERR_PTR(long error) 23 { 24 return (void *) error; 25 } 26 27 static inline long __must_check PTR_ERR(const void *ptr) 28 { 29 return (long) ptr; 30 } 31 32 static inline long __must_check IS_ERR(const void *ptr) 33 { 34 return IS_ERR_VALUE((unsigned long)ptr); 35 } 36 37 static inline long __must_check IS_ERR_OR_NULL(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 */ 49 static inline void * __must_check ERR_CAST(const void *ptr) 50 { 51 /* cast away the const */ 52 return (void *) ptr; 53 } 54 55 static inline int __must_check PTR_RET(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
