blob: bdc3dd8131d4eb95cbff12bc9c80e59cd7312704 [file] [log] [blame]
#include <linux/compiler.h>
#include <linux/types.h>
#include <asm/errno.h>
* Original kernel header comment:
* Kernel pointers have redundant information, so we can use a
* scheme where we can return either an error code or a normal
* pointer with the same return value.
* This should be a per-architecture thing, to allow different
* error and pointer decisions.
* Userspace note:
* The same principle works for userspace, because 'error' pointers
* fall down to the unused hole far from user space, as described
* in Documentation/x86/x86_64/mm.txt for x86_64 arch:
* 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
* ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
* It should be the same case for other architectures, because
* this code is used in generic kernel code.
#define MAX_ERRNO 4095
#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
static inline void * __must_check ERR_PTR(long error_)
return (void *) error_;
static inline long __must_check PTR_ERR(__force const void *ptr)
return (long) ptr;
static inline bool __must_check IS_ERR(__force const void *ptr)
return IS_ERR_VALUE((unsigned long)ptr);
#endif /* _LINUX_ERR_H */