Re: [PATCH 2/2] trace_events: fix the include file dependencies

[Frederic Weisbecker <fweisbec@gmail.com>]

On Tue, Aug 25, 2009 at 02:06:22PM +0800, Xiao Guangrong wrote:
> The TRACE_EVENT depend on the include/linux/tracepoint.h first
> and include/trace/ftrace.h later, if we include the ftrace.h early,
> It'll occur building error, like blow:
> 
> Both define TRACE_EVENT in trace_a.h and trace_b.h, if we include
> those in .c file, like this:
> 
> #define CREATE_TRACE_POINTS
> include <trace/events/trace_a.h>
> include <trace/events/trace_b.h>
> 
> There are can't work,  because the TRACE_EVENT has re-defined by
> the previous .h file
> 
> Reported-by: Wei Yongjun <yjwei@cn.fujitsu.com>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
> ---
>  include/linux/tracepoint.h   |    3 +--
>  include/trace/define_trace.h |    1 +
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> index 5984ed0..8170985 100644
> --- a/include/linux/tracepoint.h
> +++ b/include/linux/tracepoint.h
> @@ -180,6 +180,7 @@ static inline void tracepoint_synchronize_unregister(void)
>  }
>  
>  #define PARAMS(args...) args
> +#endif


Please add a comment to explain what your endifs are closing, that helps
for reviews. Especially while walking on such complicated header files,
it's a crutch.

I guess this one closes _LINUX_TRACEPOINT_H, right?


>  
>  #ifndef TRACE_EVENT
>  /*
> @@ -287,5 +288,3 @@ static inline void tracepoint_synchronize_unregister(void)
>  #define TRACE_EVENT(name, proto, args, struct, assign, print)	\
>  	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
>  #endif
> -
> -#endif
> diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h
> index 76e93bf..202cecd 100644
> --- a/include/trace/define_trace.h
> +++ b/include/trace/define_trace.h
> @@ -52,6 +52,7 @@
>  #include <trace/ftrace.h>
>  #endif
>  
> +#undef TRACE_EVENT
>  #undef TRACE_HEADER_MULTI_READ
>  
>  /* Only undef what we defined in this file */


Well, hopefully we are not missing something subtle, but
yeah that seems to solve the problem, for both CONFIG_EVENT_TRACING
and !CONFIG_EVENT_TRACING cases.
And that seems to also fit well whenever CREATE_TRACE_POINTS is
defined or not.

Other than the missing comment:

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>

Thanks.