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    SubjectRe: [PATCH v5 4/4] tracing: Have existing event_command.parse() implementations use helpers
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    On Sat, 2022-01-08 at 22:23 -0600, Tom Zanussi wrote:
    > Hi Steve,
    >
    > On Sat, 2022-01-08 at 19:54 -0500, Steven Rostedt wrote:
    > > On Tue, 14 Dec 2021 12:57:32 -0600
    > > Tom Zanussi <zanussi@kernel.org> wrote:
    > >
    > > > index da103826f27e..e6a48e8c79eb 100644
    > > > --- a/kernel/trace/trace_events_trigger.c
    > > > +++ b/kernel/trace/trace_events_trigger.c
    > > > @@ -973,7 +973,7 @@ int event_trigger_register(struct
    > > > event_command
    > > > *cmd_ops,
    > > > * @file: The trace_event_file associated with the event
    > > > * @glob: The raw string used to register the trigger
    > > > * @cmd: The cmd portion of the string used to register the
    > > > trigger
    > > > - * @param: The params portion of the string used to register the
    > > > trigger
    > > > + * @param_and_filter: The param and filter portion of the string
    > > > used to register the trigger
    > > > *
    > > > * Common implementation for event command parsing and trigger
    > > > * instantiation.
    > > > @@ -986,94 +986,53 @@ int event_trigger_register(struct
    > > > event_command *cmd_ops,
    > > > static int
    > > > event_trigger_parse(struct event_command *cmd_ops,
    > > > struct trace_event_file *file,
    > > > - char *glob, char *cmd, char *param)
    > > > + char *glob, char *cmd, char *param_and_filter)
    > > > {
    > > > struct event_trigger_data *trigger_data;
    > > > struct event_trigger_ops *trigger_ops;
    > > > - char *trigger = NULL;
    > > > - char *number;
    > > > + char *param, *filter;
    > > > + bool remove;
    > > > int ret;
    > > >
    > > > - /* separate the trigger from the filter (t:n [if filter]) */
    > > > - if (param && isdigit(param[0])) {
    > > > - trigger = strsep(&param, " \t");
    > > > - if (param) {
    > > > - param = skip_spaces(param);
    > > > - if (!*param)
    > > > - param = NULL;
    > > > - }
    > > > - }
    > > > + remove = event_trigger_check_remove(glob);
    > > >
    > > > - trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
    > >
    > > Did you mean to remove the assignment of trigger_ops here?
    >
    > Hmm, yeah, that shouldn't have been removed, but...

    Actually, it should be removed, because get_trigger_ops() is now called
    in event_trigger_alloc() in patch 3/4. And trigger_ops isn't actually
    used by unreg(), so the trigger_ops local can just be removed. For
    that matter, trigger_ops should probably be removed from the
    reg()/unreg() callbacks altogether. Will add a separate pach to do
    that.

    >
    > >
    > > > + ret = event_trigger_separate_filter(param_and_filter, &param,
    > > > &filter, false);
    > > > + if (ret)
    > > > + return ret;
    > > >
    > > > ret = -ENOMEM;
    > > > - trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
    > > > + trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
    > > > if (!trigger_data)
    > > > goto out;
    > > >
    > > > - trigger_data->count = -1;
    > > > - trigger_data->ops = trigger_ops;
    > > > - trigger_data->cmd_ops = cmd_ops;
    > > > - trigger_data->private_data = file;
    > > > - INIT_LIST_HEAD(&trigger_data->list);
    > > > - INIT_LIST_HEAD(&trigger_data->named_list);
    > > > -
    > > > - if (glob[0] == '!') {
    > > > + if (remove) {
    > > > cmd_ops->unreg(glob+1, trigger_ops, trigger_data,
    > > > file);
    > >
    > > It's still used here and below.
    > >
    > > I get a warning on this.
    >
    > I'm not getting a warning, and remove should have crashed the
    > testcases, but I'm not seeing that either.

    I'm not getting a warning because of -Wno-maybe-ininitialized. I had
    to build with W=2 to see the warning.

    Also, the testcases aren't crashing because trigger_ops is never used
    in unreg().

    I'll respin and resend later today.

    Tom

    >
    > Will have to investigate tomorrow..
    >
    > Tom
    >
    >
    > >
    > > Thanks,
    > >
    > > -- Steve
    > >
    > > > kfree(trigger_data);
    >
    >

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