Em Wed, Aug 26, 2015 at 03:46:43PM +0200, Jiri Olsa escreveu:
> Adding part of the kernel's <linux/err.h> interface:
> inline void * __must_check ERR_PTR(long error);
> inline long __must_check PTR_ERR(__force const void *ptr);
> inline bool __must_check IS_ERR(__force const void *ptr);
>
> it will be used to propagate error through pointers
> in following patches.
>
> Link: http://lkml.kernel.org/n/tip-ufgnyf683uab69anmmrab...@git.kernel.org
> Signed-off-by: Jiri Olsa <jo...@kernel.org>
> ---
> tools/include/linux/err.h | 28 ++++++++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
> create mode 100644 tools/include/linux/err.h
>
> diff --git a/tools/include/linux/err.h b/tools/include/linux/err.h
> new file mode 100644
> index 000000000000..2df92df55cfe
> --- /dev/null
> +++ b/tools/include/linux/err.h
> @@ -0,0 +1,28 @@
> +#ifndef __TOOLS_LINUX_ERR_H
> +#define __TOOLS_LINUX_ERR_H
> +
> +#include <linux/compiler.h>
> +#include <linux/types.h>
> +
> +#include <asm/errno.h>
> +
You deleted the comment in the kernel sources at this point:
/*
* 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.
*/
> +#define MAX_ERRNO 4095
Now we're dealing with user pointers, are we completely sure we can use
this trick here?
- Arnaldo
> +#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 */
> --
> 2.4.3
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