linux-stable/tools/include/linux/err.h
Arnaldo Carvalho de Melo 92151b0a23 tools include: Adopt ERR_CAST() from the kernel err.h header
Add ERR_CAST(), so that tools can use it, just like the kernel.

This addresses coccinelle checks that are being performed to tools/ in
addition to kernel sources, so lets add this to cover that and to get
tools code closer to kernel coding standards.

This originally was introduced in the kernel headers in this cset:

  d1bc8e9544 ("Add an ERR_CAST() function to complement ERR_PTR and co.")

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Wen Yang <yellowriver2010@hotmail.com>
Cc: zhong.weidong@zte.com.cn
Link: https://lkml.kernel.org/n/tip-tlt97p066zyhzqhl5jt86og7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-12-17 14:54:34 -03:00

75 lines
2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __TOOLS_LINUX_ERR_H
#define __TOOLS_LINUX_ERR_H
#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);
}
static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
{
return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
}
static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
{
if (IS_ERR(ptr))
return PTR_ERR(ptr);
else
return 0;
}
/**
* ERR_CAST - Explicitly cast an error-valued pointer to another pointer type
* @ptr: The pointer to cast.
*
* Explicitly cast an error-valued pointer to another pointer type in such a
* way as to make it clear that's what's going on.
*/
static inline void * __must_check ERR_CAST(__force const void *ptr)
{
/* cast away the const */
return (void *) ptr;
}
#endif /* _LINUX_ERR_H */