On Sat, 7 Sep 2013 10:29:00 -0500
Tom Zanussi <[email protected]> wrote:
> --- a/kernel/trace/trace_events_trigger.c
> +++ b/kernel/trace/trace_events_trigger.c
> @@ -696,6 +696,74 @@ static struct event_command trigger_traceoff_cmd = {
> .get_trigger_ops = onoff_get_trigger_ops,
> };
>
> +static void
> +snapshot_trigger(struct event_trigger_data *data)
> +{
> + tracing_snapshot();
> +}
If CONFIG_TRACER_SNAPSHOT is not defined, then we should not bother
implementing the snapshot trigger. This should be encapsulated around
ifdefs.
> +
> +static void
> +snapshot_count_trigger(struct event_trigger_data *data)
> +{
> + if (!data->count)
> + return;
> +
> + if (data->count != -1)
> + (data->count)--;
> +
> + snapshot_trigger(data);
> +}
> +
> +static int
> +register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
> + struct event_trigger_data *data,
> + struct ftrace_event_file *file)
> +{
> + int ret = register_trigger(glob, ops, data, file);
> +
> + if (ret > 0)
> + ftrace_alloc_snapshot();
> +
> + return ret;
> +}
> +
> +static int
> +snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
> + struct event_trigger_data *data)
> +{
> + return event_trigger_print("snapshot", m, (void *)data->count,
> + data->filter_str);
> +}
> +
> +static struct event_trigger_ops snapshot_trigger_ops = {
> + .func = snapshot_trigger,
> + .print = snapshot_trigger_print,
> + .init = event_trigger_init,
> + .free = event_trigger_free,
> +};
> +
> +static struct event_trigger_ops snapshot_count_trigger_ops = {
> + .func = snapshot_count_trigger,
> + .print = snapshot_trigger_print,
> + .init = event_trigger_init,
> + .free = event_trigger_free,
> +};
> +
> +static struct event_trigger_ops *
> +snapshot_get_trigger_ops(char *cmd, char *param)
> +{
> + return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
> +}
> +
> +static struct event_command trigger_snapshot_cmd = {
> + .name = "snapshot",
> + .trigger_type = ETT_SNAPSHOT,
> + .func = event_trigger_callback,
> + .reg = register_snapshot_trigger,
> + .unreg = unregister_trigger,
> + .get_trigger_ops = snapshot_get_trigger_ops,
> +};
> +
> static __init void unregister_trigger_traceon_traceoff_cmds(void)
> {
> unregister_event_command(&trigger_traceon_cmd);
> @@ -726,5 +794,11 @@ __init int register_trigger_cmds(void)
> return ret;
> }
>
> + ret = register_event_command(&trigger_snapshot_cmd);
> + if (WARN_ON(ret < 0)) {
> + unregister_trigger_traceon_traceoff_cmds();
If the snapshot trigger fails, why remove the traceon_traceoff trigger
if it succeeded? Is there some dependency that we should be worried
about?
Or is this just saying "if once trigger fails, they all fail!"?
-- Steve
> + return ret;
> + }
> +
> return 0;
> }
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