Messages in this thread Patch in this message | | | Date | Thu, 5 Feb 2015 16:29:33 -0500 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH 5/7] trace: make filter_parse_regex() provide the length of substring to compare with |
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On Thu, 5 Feb 2015 19:56:38 +0000 Al Viro <viro@ZenIV.linux.org.uk> wrote:
> From: Al Viro <viro@zeniv.linux.org.uk> > > ... by passing len by address and using it to report the length of > substring in question.
You certainly are very verbose in your change logs.
What exactly is the purpose of this patch? Clean up? Optimization?
I can't really tell. Seems like you are just moving the strlen() from outside the function into it.
> --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -1051,7 +1051,7 @@ struct filter_pred { > }; > > extern enum regex_type > -filter_parse_regex(char *buff, int len, char **search, int *not); > +filter_parse_regex(char *buff, int *len, char **search, int *not); > extern void print_event_filter(struct ftrace_event_file *file, > struct trace_seq *s); > extern int apply_event_filter(struct ftrace_event_file *file, > diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c > index 6c4a96b..6a659e1 100644 > --- a/kernel/trace/trace_events_filter.c > +++ b/kernel/trace/trace_events_filter.c > @@ -321,7 +321,7 @@ static int regex_match_end(char *str, struct regex *r, int len) > * not returns 1 if buff started with a '!' > * 0 otherwise. > */
@len above needs to be updated for kernel doc. The description should also note what *len gets set to at the end.
> -enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) > +enum regex_type filter_parse_regex(char *buff, int *len, char **search, int *not) > { > int type = MATCH_FULL; > int i; > @@ -329,13 +329,13 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) > if (buff[0] == '!') { > *not = 1; > buff++; > - len--; > + (*len)--; > } else > *not = 0; > > *search = buff; > > - for (i = 0; i < len; i++) { > + for (i = 0; i < *len; i++) { > if (buff[i] == '*') { > if (!i) { > *search = buff + 1; > @@ -350,6 +350,7 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) > } > } > } > + *len = strlen(*search);
We could optimize this even further:
*len = &buff[i] - *search;
-- Steve
> > return type; > }
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