Re: [PATCH] ftrace.h: TP_fast_assign - use do {} while (0);

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 2009-09-09 at 09:48 -0700, Joe Perches wrote:
> Perhaps this is a more kernel style standard way to allow
> local variables in TP_fast_assign.
> 
> http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commitdiff;h=a9c1c3abe1160a5632e48c929b02b740556bf423
> 
> Signed-off-by: Joe Perches <joe@perches.com>
> 
> diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
> index f64fbaa..4c99bdc 100644
> --- a/include/trace/ftrace.h
> +++ b/include/trace/ftrace.h
> @@ -142,7 +142,7 @@
>  #define TP_printk(fmt, args...) "%s, %s\n", #fmt, __stringify(args)
>  
>  #undef TP_fast_assign
> -#define TP_fast_assign(args...) args
> +#define TP_fast_assign(args...) do { args } while (0);
>  
>  #undef TP_perf_assign
>  #define TP_perf_assign(args...)

This is not a normal macro that is used globally. I like the referenced
commit better, because it shows where it is used what is happening.
Note, TP_fast_assign is just a parameter into another macro, and using
do { } while (0) is not really going to help change anything. This
doesn't even remove a checkpatch warning.

-- Steve