On Thu, 2 Apr 2015 16:47:40 +0900
Namhyung Kim <[email protected]> wrote:


> > +static void update_event_printk(struct ftrace_event_call *call,
> > +                           struct trace_enum_map *map)
> > +{
> > +   char *ptr;
> > +   int quote = 0;
> > +   int len = strlen(map->enum_string);
> > +
> > +   for (ptr = call->print_fmt; *ptr; ptr++) {
> > +           if (*ptr == '\\') {
> > +                   ptr++;
> > +                   /* paranoid */
> > +                   if (!*ptr)
> > +                           break;
> > +                   continue;
> > +           }
> > +           if (*ptr == '"') {
> > +                   quote ^= 1;
> > +                   continue;
> > +           }
> > +           if (quote)
> > +                   continue;
> > +           if (isdigit(*ptr)) {
> > +                   /* skip numbers */
> > +                   do {
> > +                           ptr++;
> > +                   } while (isalnum(*ptr) || *ptr == '_');
> > +                   /* we went one too many */
> 
> Hmm.. it looks like to skip variable name after a number.  Shouldn't it be 
> 
>                       do { ptr++; } while (isdigit(*ptr));
> 
> ?

A variable can not be appended to a number in C. But alpha characters
like 1ULL can be, and they need to be skipped. Hmm, I probably could
remove the check for '_' though.

> 
> 
> > +                   ptr--;
> > +                   continue;
> > +           }
> > +           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;
> > +                           continue;
> 
> I guess it also needs to decrease the ptr here.

I thought about this when writing it and realized that it just replaced
a variable and two variables can not be bumped against each other.
There must be something in between them, and we can skip whatever that
something is.

I could add a comment about that.

> 
> 
> > +                   }
> > +                   do {
> > +                           ptr++;
> > +                   } while (isalnum(*ptr) || *ptr == '_');
> > +                   /* we went one too many */
> > +                   ptr--;
> > +                   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)
> > +                   last_i = 0;
> 
> I think it needs to update the last_system here.

Ouch, yeah you're right!

Will fix.

Thanks,

-- Steve

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