Re: [PATCH 01/61] Rules on how to use sysfs in userspace programs

Pavel Machek
2007-07-12T20:41:51Z

On Wed 2007-07-11 16:31:20, Greg Kroah-Hartman wrote:
> From: Kay Sievers <kay.sievers@vrfy.org>
>
> Here's a document to help clear things up.
>
> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> ---
> Documentation/sysfs-rules.txt | 166 +++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 166 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/sysfs-rules.txt
>
> diff --git a/Documentation/sysfs-rules.txt b/Documentation/sysfs-rules.txt
> new file mode 100644
> index 0000000..42861bb
> --- /dev/null
> +++ b/Documentation/sysfs-rules.txt
> @@ -0,0 +1,166 @@
> +Rules on how to access information in the Linux kernel sysfs
> +
> +The kernel exported sysfs exports internal kernel implementation-details
> +and depends on internal kernel structures and layout. It is agreed upon
> +by the kernel developers that the Linux kernel does not provide a stable
> +internal API. As sysfs is a direct export of kernel internal
> +structures, the sysfs interface can not provide a stable interface eighter,
> +it may always change along with internal kernel changes.

It is also agreed upon by the kernel developers that the Linux kernel
does have a stable user<->kernel API... so we have a small problem
here.

Maybe solution is to declare /sys unstable, but... perhaps /sys can
stop mirroring internal structures? I do not think we should codify
our failure to keep /sys stable here.
Pavel
--
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