Re: [RFC][PATCH 2/2] [PATCH 2/2] tracing: Make event based trace_printk()

[Steven Rostedt <rostedt@goodmis.org>]

On Thu, 2010-11-18 at 13:50 +0800, Lai Jiangshan wrote:
> On 11/18/2010 11:58 AM, Steven Rostedt wrote:
> > +#define trace_printk(fmt, args...)					\
> > +	do {								\
> > +		static struct event_printk_struct			\
> > +		__attribute__((__aligned__(4)))				\
> > +		__attribute__((section("_trace_printk")))		\
> > +		______t = {						\
> > +			.format = fmt,					\
> 
> if fmt is not constant, the compiler will complain...

Ah you are right. I added that after I wrote all this code and wanted
the format to print in the file. The original code required the compile
check below.

-- Steve

> 
> > +			.func = __func__,				\
> > +			.file = __FILE__,				\
> > +			.line = __LINE__,				\
> > +		};							\
> > +		__trace_printk_check_format(fmt, ##args);		\
> > +		if (!__builtin_constant_p(fmt))				\
> > +			trace_printk_can_only_have_constant_format();	\
> 
> so this is not need.
> 
> > +		if (unlikely(__event_printk_test(&______t.enable)))	\
> > +			__trace_bprintk(_THIS_IP_, fmt, ##args); \
> > +	} while (0)