1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_ERR_H 3 #define _LINUX_ERR_H 4 5 #include <linux/compiler.h> 6 #include <linux/types.h> 7 8 #include <asm/errno.h> 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 normal 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((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) 23 24 static inline void * __must_check ERR_PTR(long error) 25 { 26 return (void *) error; 27 } 28 29 static inline long __must_check PTR_ERR(__force const void *ptr) 30 { 31 return (long) ptr; 32 } 33 34 static inline bool __must_check IS_ERR(__force const void *ptr) 35 { 36 return IS_ERR_VALUE((unsigned long)ptr); 37 } 38 39 static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr) 40 { 41 return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)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 */ 51 static inline void * __must_check ERR_CAST(__force const void *ptr) 52 { 53 /* cast away the const */ 54 return (void *) ptr; 55 } 56 57 static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr) 58 { 59 if (IS_ERR(ptr)) 60 return PTR_ERR(ptr); 61 else 62 return 0; 63 } 64 65 /* Deprecated */ 66 #define PTR_RET(p) PTR_ERR_OR_ZERO(p) 67 68 #endif 69 70 #endif /* _LINUX_ERR_H */ 71