On Mon, Nov 29, 2021 at 12:07:40PM +0100,
Daniel Bristot de Oliveira wrote:
> +/*
> + * enable_tracer_by_name - enable a tracer on the given instance
> + */
> +int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer)
> +{
> + enum tracefs_tracers t;
> + int retval;
> +
> + t = TRACEFS_TRACER_CUSTOM;
> +
> + debug_msg("enabling %s tracer\n", tracer);
> +
> + retval = tracefs_tracer_set(inst, t, tracer);
The comment of parameters used for tracefs_tracer_set() says:
'
* tracefs_set_tracer - function to set the tracer
* @instance: ftrace instance, can be NULL for top tracing instance
* @tracer: The tracer enum that defines the tracer to be set
* @t: A tracer name if TRACEFS_TRACER_CUSTOM is passed in for @tracer
'
tracefs_tracer_set(inst, tracer, t); @tracer is enum and @t is tracer
name. this is not important.
> + if (retval < 0) {
> + if (errno == ENODEV)
> + err_msg("tracer %s not found!\n", tracer);
> +
> + err_msg("failed to enable the tracer %s\n", tracer);
> + return -1;
> + }
> +
> + return 0;
> +}
