Re: [PATCH v3 01/10] tracing: Update cond flag when enabling or disabling a trigger

[Tom Zanussi <tom.zanussi@linux.intel.com>]

On Fri, 2015-06-12 at 14:01 -0400, Steven Rostedt wrote:
> Why v3 in the subject?
> 

It was v3 of the patch he sent, which came at about v4 of the original
patchset.  I guess that just causes confusion, so I'll keep the version
numbers the same for a patchset.

> On Mon,  8 Jun 2015 16:32:00 -0500
> Tom Zanussi <tom.zanussi@linux.intel.com> wrote:
> 
> > When a trigger is enabled, the cond flag should be set beforehand,
> > otherwise a trigger that's expecting to process a trace record
> > (e.g. one with post_trigger set) could be invoked without one.
> > 
> > Likewise a trigger's cond flag should be reset after it's disabled,
> > not before.
> > 
> > Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> > Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
> 
> Why is Daniel signed off by here?
> 

Daniel sent me the original problem report and attempt at a patch - I
started from that but fixed it up but still wanted to give him credit.
>From now on, I'll keep follow-ons separate (it's kind of unusual to have
people sending patches for patchsets still under review, so wasn't sure
about that).

Tom

> -- Steve
> 
> > ---
> >  kernel/trace/trace_events_trigger.c | 10 ++++++----
> >  1 file changed, 6 insertions(+), 4 deletions(-)
> > 
> > diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
> > index 42a4009..4d2f3cc 100644
> > --- a/kernel/trace/trace_events_trigger.c
> > +++ b/kernel/trace/trace_events_trigger.c
> > @@ -543,11 +543,12 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops,
> >  	list_add_rcu(&data->list, &file->triggers);
> >  	ret++;
> >  
> > +	update_cond_flag(file);
> >  	if (trace_event_trigger_enable_disable(file, 1) < 0) {
> >  		list_del_rcu(&data->list);
> > +		update_cond_flag(file);
> >  		ret--;
> >  	}
> > -	update_cond_flag(file);
> >  out:
> >  	return ret;
> >  }
> > @@ -575,8 +576,8 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
> >  		if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
> >  			unregistered = true;
> >  			list_del_rcu(&data->list);
> > -			update_cond_flag(file);
> >  			trace_event_trigger_enable_disable(file, 0);
> > +			update_cond_flag(file);
> >  			break;
> >  		}
> >  	}
> > @@ -1319,11 +1320,12 @@ static int event_enable_register_trigger(char *glob,
> >  	list_add_rcu(&data->list, &file->triggers);
> >  	ret++;
> >  
> > +	update_cond_flag(file);
> >  	if (trace_event_trigger_enable_disable(file, 1) < 0) {
> >  		list_del_rcu(&data->list);
> > +		update_cond_flag(file);
> >  		ret--;
> >  	}
> > -	update_cond_flag(file);
> >  out:
> >  	return ret;
> >  }
> > @@ -1344,8 +1346,8 @@ static void event_enable_unregister_trigger(char *glob,
> >  		    (enable_data->file == test_enable_data->file)) {
> >  			unregistered = true;
> >  			list_del_rcu(&data->list);
> > -			update_cond_flag(file);
> >  			trace_event_trigger_enable_disable(file, 0);
> > +			update_cond_flag(file);
> >  			break;
> >  		}
> >  	}
>