1b2441318SGreg Kroah-Hartman /* SPDX-License-Identifier: GPL-2.0 */ 21da177e4SLinus Torvalds #ifndef _LINUX_ERR_H 31da177e4SLinus Torvalds #define _LINUX_ERR_H 41da177e4SLinus Torvalds 51da177e4SLinus Torvalds #include <linux/compiler.h> 6a5ed3ceeSJoe Perches #include <linux/types.h> 71da177e4SLinus Torvalds 81da177e4SLinus Torvalds #include <asm/errno.h> 91da177e4SLinus Torvalds 101da177e4SLinus Torvalds /* 111da177e4SLinus Torvalds * Kernel pointers have redundant information, so we can use a 12a5ed3ceeSJoe Perches * scheme where we can return either an error code or a normal 131da177e4SLinus Torvalds * pointer with the same return value. 141da177e4SLinus Torvalds * 151da177e4SLinus Torvalds * This should be a per-architecture thing, to allow different 161da177e4SLinus Torvalds * error and pointer decisions. 171da177e4SLinus Torvalds */ 18fa79837dSRalf Baechle #define MAX_ERRNO 4095 19fa79837dSRalf Baechle 20ebba5f9fSRandy Dunlap #ifndef __ASSEMBLY__ 21ebba5f9fSRandy Dunlap 22*4d744ce9SJames Seo /** 23*4d744ce9SJames Seo * IS_ERR_VALUE - Detect an error pointer. 24*4d744ce9SJames Seo * @x: The pointer to check. 25*4d744ce9SJames Seo * 26*4d744ce9SJames Seo * Like IS_ERR(), but does not generate a compiler warning if result is unused. 27*4d744ce9SJames Seo */ 28aa00edc1SLinus Torvalds #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) 2907ab67c8SLinus Torvalds 30*4d744ce9SJames Seo /** 31*4d744ce9SJames Seo * ERR_PTR - Create an error pointer. 32*4d744ce9SJames Seo * @error: A negative error code. 33*4d744ce9SJames Seo * 34*4d744ce9SJames Seo * Encodes @error into a pointer value. Users should consider the result 35*4d744ce9SJames Seo * opaque and not assume anything about how the error is encoded. 36*4d744ce9SJames Seo * 37*4d744ce9SJames Seo * Return: A pointer with @error encoded within its value. 38*4d744ce9SJames Seo */ ERR_PTR(long error)39e47103b1SJani Nikulastatic inline void * __must_check ERR_PTR(long error) 401da177e4SLinus Torvalds { 411da177e4SLinus Torvalds return (void *) error; 421da177e4SLinus Torvalds } 431da177e4SLinus Torvalds 44*4d744ce9SJames Seo /** 45*4d744ce9SJames Seo * PTR_ERR - Extract the error code from an error pointer. 46*4d744ce9SJames Seo * @ptr: An error pointer. 47*4d744ce9SJames Seo * Return: The error code within @ptr. 48*4d744ce9SJames Seo */ PTR_ERR(__force const void * ptr)49e7152b97SDan Carpenterstatic inline long __must_check PTR_ERR(__force const void *ptr) 501da177e4SLinus Torvalds { 511da177e4SLinus Torvalds return (long) ptr; 521da177e4SLinus Torvalds } 531da177e4SLinus Torvalds 54*4d744ce9SJames Seo /** 55*4d744ce9SJames Seo * IS_ERR - Detect an error pointer. 56*4d744ce9SJames Seo * @ptr: The pointer to check. 57*4d744ce9SJames Seo * Return: true if @ptr is an error pointer, false otherwise. 58*4d744ce9SJames Seo */ IS_ERR(__force const void * ptr)59a5ed3ceeSJoe Perchesstatic inline bool __must_check IS_ERR(__force const void *ptr) 601da177e4SLinus Torvalds { 6107ab67c8SLinus Torvalds return IS_ERR_VALUE((unsigned long)ptr); 621da177e4SLinus Torvalds } 631da177e4SLinus Torvalds 64*4d744ce9SJames Seo /** 65*4d744ce9SJames Seo * IS_ERR_OR_NULL - Detect an error pointer or a null pointer. 66*4d744ce9SJames Seo * @ptr: The pointer to check. 67*4d744ce9SJames Seo * 68*4d744ce9SJames Seo * Like IS_ERR(), but also returns true for a null pointer. 69*4d744ce9SJames Seo */ IS_ERR_OR_NULL(__force const void * ptr)70a5ed3ceeSJoe Perchesstatic inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr) 71603c4ba9SPhil Carmody { 72dfffa587SViresh Kumar return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr); 73603c4ba9SPhil Carmody } 74603c4ba9SPhil Carmody 75d1bc8e95SDavid Howells /** 76d1bc8e95SDavid Howells * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type 77d1bc8e95SDavid Howells * @ptr: The pointer to cast. 78d1bc8e95SDavid Howells * 79d1bc8e95SDavid Howells * Explicitly cast an error-valued pointer to another pointer type in such a 80d1bc8e95SDavid Howells * way as to make it clear that's what's going on. 81d1bc8e95SDavid Howells */ ERR_CAST(__force const void * ptr)82e7152b97SDan Carpenterstatic inline void * __must_check ERR_CAST(__force const void *ptr) 83d1bc8e95SDavid Howells { 84d1bc8e95SDavid Howells /* cast away the const */ 85d1bc8e95SDavid Howells return (void *) ptr; 86d1bc8e95SDavid Howells } 87d1bc8e95SDavid Howells 88*4d744ce9SJames Seo /** 89*4d744ce9SJames Seo * PTR_ERR_OR_ZERO - Extract the error code from a pointer if it has one. 90*4d744ce9SJames Seo * @ptr: A potential error pointer. 91*4d744ce9SJames Seo * 92*4d744ce9SJames Seo * Convenience function that can be used inside a function that returns 93*4d744ce9SJames Seo * an error code to propagate errors received as error pointers. 94*4d744ce9SJames Seo * For example, ``return PTR_ERR_OR_ZERO(ptr);`` replaces: 95*4d744ce9SJames Seo * 96*4d744ce9SJames Seo * .. code-block:: c 97*4d744ce9SJames Seo * 98*4d744ce9SJames Seo * if (IS_ERR(ptr)) 99*4d744ce9SJames Seo * return PTR_ERR(ptr); 100*4d744ce9SJames Seo * else 101*4d744ce9SJames Seo * return 0; 102*4d744ce9SJames Seo * 103*4d744ce9SJames Seo * Return: The error code within @ptr if it is an error pointer; 0 otherwise. 104*4d744ce9SJames Seo */ PTR_ERR_OR_ZERO(__force const void * ptr)1056e8b8726SRusty Russellstatic inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr) 106fa9ee9c4SUwe Kleine-König { 107fa9ee9c4SUwe Kleine-König if (IS_ERR(ptr)) 108fa9ee9c4SUwe Kleine-König return PTR_ERR(ptr); 109fa9ee9c4SUwe Kleine-König else 110fa9ee9c4SUwe Kleine-König return 0; 111fa9ee9c4SUwe Kleine-König } 112fa9ee9c4SUwe Kleine-König 113ebba5f9fSRandy Dunlap #endif 114ebba5f9fSRandy Dunlap 1151da177e4SLinus Torvalds #endif /* _LINUX_ERR_H */ 116