Re: [PATCH 3/4] perf session: Move an error code assignment in __perf_session__set_tracepoints_handlers()

Masami Hiramatsu
2017-01-23T22:56:49Z

On Mon, 23 Jan 2017 16:25:23 +0100
SF Markus Elfring <elfring@users.sourceforge.net> wrote:

> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Mon, 23 Jan 2017 15:43:13 +0100
>
> A local variable was set to an error code before a concrete error situation
> was detected. Thus move the corresponding assignment into an if branch
> to indicate a software failure there.
>
> This issue was detected by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> tools/perf/util/session.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index f268201048a0..98605ad4affd 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -2050,10 +2050,10 @@ int __perf_session__set_tracepoints_handlers(struct perf_session *session,
> evsel = perf_evlist__find_tracepoint_by_name(session->evlist, assocs[i].name);
> if (evsel == NULL)
> continue;
> -
> - err = -EEXIST;
> - if (evsel->handler != NULL)
> + if (evsel->handler) {
> + err = -EEXIST;
> goto out;
> + }
> evsel->handler = assocs[i].handler;
> }

Hmm, if we cleanup this function, it might be better not to use goto as below.

int __perf_session__set_tracepoints_handlers(struct perf_session *session,
const struct perf_evsel_str_handler *assocs,
size_t nr_assocs)
{
struct perf_evsel *evsel;
size_t i;
int err = 0;

for (i = 0; i < nr_assocs; i++) {
/*
* Adding a handler for an event not in the session,
* just ignore it.
*/
evsel = perf_evlist__find_tracepoint_by_name(session->evlist, assocs[i].name);
if (evsel == NULL)
continue;

if (evsel->handler != NULL) {
err = -EEXIST;
break;
}
evsel->handler = assocs[i].handler;
}

return err;
}

Thank you,

--
Masami Hiramatsu <mhiramat@kernel.org>