Re: [patch] trace: find the correct ftrace event

From: Steven Rostedt
Date: Sat Mar 20 2010 - 09:37:24 EST


On Sat, 2010-03-20 at 16:19 +0300, Dan Carpenter wrote:
> The original code doesn't work because "call" is never NULL there.

A one line change would have done the same ;-)

> Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
> ---
> My code should work, but it seems like there should but it seems like
> there should be a more elegant way to do this?
>
> diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
> index 4615f62..6070c70 100644
> --- a/kernel/trace/trace_events_filter.c
> +++ b/kernel/trace/trace_events_filter.c
> @@ -1388,16 +1388,19 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
> struct event_filter *filter;
> struct filter_parse_state *ps;
> struct ftrace_event_call *call = NULL;
> + int found = 0;
>
> mutex_lock(&event_mutex);
>
> list_for_each_entry(call, &ftrace_events, list) {
> - if (call->id == event_id)
> + if (call->id == event_id) {
> + found = 1;
> break;
> + }
> }
>
> err = -EINVAL;
> - if (!call)

if (call == &ftrace_events)

-- Steve

> + if (!found)
> goto out_unlock;
>
> err = -EEXIST;


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