Re: [PATCH 07/18 v3] tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

[Namhyung Kim <namhyung@kernel.org>]

Hi Steve,

On Mon, Apr 06, 2015 at 07:52:37AM -0400, Steven Rostedt wrote:
> On Mon, 6 Apr 2015 13:54:33 +0900
> Namhyung Kim <namhyung@kernel.org> wrote:
> 
> 
> > > +		if (isalpha(*ptr) || *ptr == '_') {
> > > +			if (strncmp(map->enum_string, ptr, len) == 0 &&
> > > +			    !isalnum(ptr[len]) && ptr[len] != '_') {
> > > +				ptr = enum_replace(ptr, map, len);
> > > +				/* Hmm, enum string smaller than value */
> > > +				if (WARN_ON_ONCE(!ptr))
> > > +					return;
> > > +				/*
> > > +				 * No need to decrement here, as enum_replace()
> > > +				 * returns the pointer to the character passed
> > > +				 * the enum, and two enums can not be placed
> > > +				 * back to back without something in between.
> > > +				 * We can skip that something in between.
> > > +				 */
> > > +				continue;
> > 
> > Maybe I'm becoming a bit paranoid, what I worried was like this:
> > 
> >   ENUM1\"ENUM2\"
> > 
> > In this case, it skips the backslash and makes quotation effective..
> 
> The only time a backslash is OK is if it's in a quote, where we do not
> process enums there anyway.
> 
> The above isn't valid C outside of quotes, so I'm still not worried.

OK

> 
> > 
> > 
> > > +			}
> > > +		skip_more:
> > > +			do {
> > > +				ptr++;
> > > +			} while (isalnum(*ptr) || *ptr == '_');
> > > +			/*
> > > +			 * If what comes after this variable is a '.' or
> > > +			 * '->' then we can continue to ignore that string.
> > > +			 */
> > > +			if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
> > > +				ptr += *ptr == '.' ? 1 : 2;
> > > +				goto skip_more;
> > > +			}
> > > +			/*
> > > +			 * Once again, we can skip the delimiter that came
> > > +			 * after the string.
> > > +			 */
> > > +			continue;
> > > +		}
> > > +	}
> > > +}
> > > +
> > > +void trace_event_enum_update(struct trace_enum_map **map, int len)
> > > +{
> > > +	struct ftrace_event_call *call, *p;
> > > +	const char *last_system = NULL;
> > > +	int last_i;
> > > +	int i;
> > > +
> > > +	down_write(&trace_event_sem);
> > > +	list_for_each_entry_safe(call, p, &ftrace_events, list) {
> > > +		/* events are usually grouped together with systems */
> > > +		if (!last_system || call->class->system != last_system) {
> > 
> > I think simply checking "call->class->system != last_system" would work.
> 
> I think you are correct, but I'm not sure I want to change it. Mainly
> because it's more readable that way. The !last_system is basically the
> "this is first time". Leaving it out may cause people to think it's
> wrong.
> 
> But I may change my mind and remove it anyway ;-)
> 
> If there's other things wrong with this patch, I may update this too.
> 
> Thanks for reviewing.

OK.  You can add my Acked-by if you like..

Thanks,
Namhyung