On Mon, 25 Feb 2008 15:10:27 +0900, Kohei KaiGai said:
quoted text
> [PATCH 1/3] add a private data field within kobj_attribute structure.

quoted text
> diff --git a/Documentation/kobject.txt b/Documentation/kobject.txt
> index bf3256e..efa5d71 100644
> --- a/Documentation/kobject.txt
> +++ b/Documentation/kobject.txt
> @@ -207,6 +207,12 @@ Both types of attributes used here, with a kobject that has been created
>  with the kobject_create_and_add(), can be of type kobj_attribute, so no
>  special custom attribute is needed to be created.
> 
> +The simple kobj_attribute is prototyped at include/linux/kobject.h, and can
> +contain your own show()/store() method and private data.
> +When an attribute is accessed, these methods are invoked with kobject,
> +kobj_attribute and read/write buffer. The method can refer the private data
> +via given kobj_attribute, to show/store itself in the text representation.
> +
>  See the example module, samples/kobject/kobject-example.c for an
>  implementation of a simple kobject and attributes.

OK, I'm an idiot, so I re-read this several times, and looked at patch 3/3
that added the sample code, and I'm still confoozled.

Who creates/destroys/manages this "read/write buffer", and/or how does the
method know how large a buffer is available, so (for example) it can use the
strn* versions of string functions to be sure not to run off the end?  Does
this buffer have any lifetime rules attached to it?