Re: [PATCH 4/4] compat: add some tracing backport work

[Johannes Berg <johannes@sipsolutions.net>]

In other words:

>  #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,27))

I'd change this to 2.6.33 so

>  #include_next <linux/tracepoint.h>

I don't have to think about this:

> +/* Backports f42c85e7 */
> +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30))
> +#undef TP_STRUCT__entry
> +#define TP_STRUCT__entry(args...) args
> +#endif
> +
> +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33))
> +/* Backports 091ad365, a rename */
> +#define DECLARE_EVENT_CLASS TRACE_EVENT_TEMPLATE
> +
> +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,30))
> +#define TP_PROTO TPPROTO
> +#define TP_ARGS TPARGS
> +#define TP_FMT TPFMT
> +#define TP_RAW_FMT TPRAWFMT
> +#endif
> +
> +#endif


This seems worthwhile and looks good:

> +#else /* just disable tracing */
> +
> +/* Disable all tracing */
> +#undef TRACE_EVENT
> +#define TRACE_EVENT(name, proto, ...) \
> +static inline void trace_ ## name(proto) {}
> +#undef DECLARE_EVENT_CLASS
> +#define DECLARE_EVENT_CLASS(...)
> +#undef DEFINE_EVENT
> +#define DEFINE_EVENT(evt_class, name, proto, ...) \
> +static inline void trace_ ## name(proto) {}
> +
> +#define TP_PROTO(args...)  args
> +#define TP_ARGS(args...)   args
> +#define TP_CONDITION(args...)      args

That doesn't seem to be needed since these are used inside the other
macros only?

> +struct tracepoint_iter {
> +};

Not sure why that would be needed?

johannes