Re: [for-next][PATCH 4/5] tracing: Have the historgram use the result of str_has_prefix() for len of prefix

From: Namhyung Kim
Date: Sat Dec 22 2018 - 22:36:16 EST


On Sat, Dec 22, 2018 at 11:20:11AM -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
>
> As str_has_prefix() returns the length on match, we can use that for the
> updating of the string pointer instead of recalculating the prefix size.
>
> Cc: Tom Zanussi <zanussi@xxxxxxxxxx>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> ---
> kernel/trace/trace_events_hist.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 0d878dcd1e4b..449d90cfa151 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -4342,12 +4342,13 @@ static int parse_actions(struct hist_trigger_data *hist_data)
> unsigned int i;
> int ret = 0;
> char *str;
> + int len;
>
> for (i = 0; i < hist_data->attrs->n_actions; i++) {
> str = hist_data->attrs->action_str[i];
>
> - if (str_has_prefix(str, "onmatch(")) {
> - char *action_str = str + sizeof("onmatch(") - 1;
> + if ((len = str_has_prefix(str, "onmatch("))) {
> + char *action_str = str + len;

Ah you did it here.

Thanks,
Namhyung


>
> data = onmatch_parse(tr, action_str);
> if (IS_ERR(data)) {
> @@ -4355,8 +4356,8 @@ static int parse_actions(struct hist_trigger_data *hist_data)
> break;
> }
> data->fn = action_trace;
> - } else if (str_has_prefix(str, "onmax(")) {
> - char *action_str = str + sizeof("onmax(") - 1;
> + } else if ((len = str_has_prefix(str, "onmax("))) {
> + char *action_str = str + len;
>
> data = onmax_parse(action_str);
> if (IS_ERR(data)) {
> --
> 2.19.2
>
>