Re: [PATCH v3 1/3] bpf: Add new bpf map type to store the pointer to struct perf_event

[Peter Zijlstra <peterz@infradead.org>]

On Thu, Jul 23, 2015 at 09:42:40AM +0000, Kaixu Xia wrote:
> +static struct perf_event *convert_map_with_perf_event(void *value)
> +{
> +	struct perf_event *event;
> +	u32 fd;
> +
> +	fd = *(u32 *)value;
> +
> +	event = perf_event_get(fd);
> +	if (IS_ERR(event))
> +		return NULL;
> +
> +	/* limit the event type to PERF_TYPE_RAW
> +	 * and PERF_TYPE_HARDWARE.
> +	 */
> +	if (event->attr.type != PERF_TYPE_RAW &&
> +	    event->attr.type != PERF_TYPE_HARDWARE)
> +		return NULL;

Aside from the ref-leak already mentioned; please introduce something
like:

const struct perf_event_attr *perf_event_attrs(struct perf_event *event);

To avoid having to poke inside of the event outside of perf code.

> +
> +	return event;
> +}