Re: [PATCH 8/6] CodingGuidelines: also mention MAYBE_UNUSED

> > Yes, it would be fine to use MAYBE_UNUSED in a case like this.
> 
> It turns out that I was, without realizing it myself, making an
> oblique reference to your patch 7/6 ;-)
> 
> Perhaps something along this line?

> diff --git c/Documentation/CodingGuidelines w/Documentation/CodingGuidelines
> index d0fc7cfe60..3263245b03 100644
> --- c/Documentation/CodingGuidelines
> +++ w/Documentation/CodingGuidelines
> @@ -262,8 +262,9 @@ For C programs:
>     like "error: unused parameter 'foo' [-Werror=unused-parameter]",
>     which indicates that a function ignores its argument. If the unused
>     parameter can't be removed (e.g., because the function is used as a
> -   callback and has to match a certain interface), you can annotate the
> -   individual parameters with the UNUSED keyword, like "int foo UNUSED".
> +   callback and has to match a certain interface), you can annotate
> +   the individual parameters with the UNUSED (or MAYBE_UNUSED)
> +   keyword, like "int foo UNUSED".

> +/*
> + * UNUSED marks a function parameter that is always unused.
> + *
> + * A callback interface may dictate that a function accepts a
> + * parameter at that position, but the implementation of the function
> + * may not need to use the parameter.  In such a case, mark the parameter
> + * with UNUSED.
> + *
> + * When a parameter may be used or unused, depending on conditional
> + * compilation, consider using MAYBE_UNUSED instead.
> + */

> +/*
> + * MAYBE_UNUSED marks a function parameter that may be unused, but
> + * whose use is not an error.
> + *
> + * Depending on a configuration, all uses of a function parameter may
> + * become #ifdef'ed away.  Marking such a parameter with UNUSED would
> + * give a warning in a compilation where the parameter is indeed used,
> + * and not marking such a parameter would give a warning in a
> + * compilation where the parameter is unused.
> + */
>  #define MAYBE_UNUSED __attribute__((__unused__))