include/linux/err.h

   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 */