Re: [PATCH] tracing/filters: add filter_mutex to protect filterpredicates

From: Ingo Molnar
Date: Thu Apr 16 2009 - 20:32:24 EST



* Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:

> Tom Zanussi wrote:
> > This patch adds a filter_mutex to prevent the filter predicates from
> > being accessed concurrently by various external functions.
> >
> > It's based on a previous patch by Li Zefan:
> > "[PATCH 7/7] tracing/filters: make filter preds RCU safe"
> >
> > but any problems with it were added by me. ;-)
> >
> > Signed-off-by: Tom Zanussi <tzanussi@xxxxxxxxx>
> >
>
> Reviewed-and-tested-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
>
> except:
>
> > @@ -348,17 +399,15 @@ int filter_add_subsystem_pred(struct event_subsystem *system,
> > if (strcmp(call->system, system->name))
> > continue;
> >
> > - if (!find_event_field(call, pred->field_name))
> > - continue;
> > -
> > - err = filter_add_pred(call, pred);
> > + err = __filter_add_pred(call, pred);
> > if (err == -ENOMEM) {
> > system->preds[system->n_preds] = NULL;
> > - return err;
> > + system->n_preds--;
> > + break;
>
> now we return 0 but not ENOMEM in this failure case.

ok - i'll wait for this fix.

Ingo
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