Line data    Source code

       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             : /**
      23             :  * IS_ERR_VALUE - Detect an error pointer.
      24             :  * @x: The pointer to check.
      25             :  *
      26             :  * Like IS_ERR(), but does not generate a compiler warning if result is unused.
      27             :  */
      28             : #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)
      29             : 
      30             : /**
      31             :  * ERR_PTR - Create an error pointer.
      32             :  * @error: A negative error code.
      33             :  *
      34             :  * Encodes @error into a pointer value. Users should consider the result
      35             :  * opaque and not assume anything about how the error is encoded.
      36             :  *
      37             :  * Return: A pointer with @error encoded within its value.
      38             :  */
      39             : static inline void * __must_check ERR_PTR(long error)
      40             : {
      41          14 :         return (void *) error;
      42             : }
      43             : 
      44             : /**
      45             :  * PTR_ERR - Extract the error code from an error pointer.
      46             :  * @ptr: An error pointer.
      47             :  * Return: The error code within @ptr.
      48             :  */
      49             : static inline long __must_check PTR_ERR(__force const void *ptr)
      50             : {
      51          28 :         return (long) ptr;
      52             : }
      53             : 
      54             : /**
      55             :  * IS_ERR - Detect an error pointer.
      56             :  * @ptr: The pointer to check.
      57             :  * Return: true if @ptr is an error pointer, false otherwise.
      58             :  */
      59             : static inline bool __must_check IS_ERR(__force const void *ptr)
      60             : {
      61       19177 :         return IS_ERR_VALUE((unsigned long)ptr);
      62             : }
      63             : 
      64             : /**
      65             :  * IS_ERR_OR_NULL - Detect an error pointer or a null pointer.
      66             :  * @ptr: The pointer to check.
      67             :  *
      68             :  * Like IS_ERR(), but also returns true for a null pointer.
      69             :  */
      70             : static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
      71             : {
      72         185 :         return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
      73             : }
      74             : 
      75             : /**
      76             :  * ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
      77             :  * @ptr: The pointer to cast.
      78             :  *
      79             :  * Explicitly cast an error-valued pointer to another pointer type in such a
      80             :  * way as to make it clear that's what's going on.
      81             :  */
      82             : static inline void * __must_check ERR_CAST(__force const void *ptr)
      83             : {
      84             :         /* cast away the const */
      85             :         return (void *) ptr;
      86             : }
      87             : 
      88             : /**
      89             :  * PTR_ERR_OR_ZERO - Extract the error code from a pointer if it has one.
      90             :  * @ptr: A potential error pointer.
      91             :  *
      92             :  * Convenience function that can be used inside a function that returns
      93             :  * an error code to propagate errors received as error pointers.
      94             :  * For example, ``return PTR_ERR_OR_ZERO(ptr);`` replaces:
      95             :  *
      96             :  * .. code-block:: c
      97             :  *
      98             :  *      if (IS_ERR(ptr))
      99             :  *              return PTR_ERR(ptr);
     100             :  *      else
     101             :  *              return 0;
     102             :  *
     103             :  * Return: The error code within @ptr if it is an error pointer; 0 otherwise.
     104             :  */
     105             : static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
     106             : {
     107           1 :         if (IS_ERR(ptr))
     108           0 :                 return PTR_ERR(ptr);
     109             :         else
     110             :                 return 0;
     111             : }
     112             : 
     113             : #endif
     114             : 
     115             : #endif /* _LINUX_ERR_H */