Re: [ndctl PATCH 2/5] cxl: add an optional pid check to event parsing

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Thu, 10 Nov 2022 19:20:05 -0800
alison.schofield@intel.com wrote:

> From: Alison Schofield <alison.schofield@intel.com>
> 
> When parsing CXL events, callers may only be interested in events
> that originate from the current process. Introduce an optional
> argument to the event trace context: event_pid. When event_pid is
> present, only include events with a matching pid in the returned
> JSON list. It is not a failure to see other, non matching results.
> Simply skip those.
> 
> The initial use case for this is the listing of media errors,
> where only the media errors requested by this process are wanted.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Makes sense to me

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  cxl/event_trace.c | 5 +++++
>  cxl/event_trace.h | 1 +
>  2 files changed, 6 insertions(+)
> 
> diff --git a/cxl/event_trace.c b/cxl/event_trace.c
> index a973a1f62d35..70ab892bbfcb 100644
> --- a/cxl/event_trace.c
> +++ b/cxl/event_trace.c
> @@ -207,6 +207,11 @@ static int cxl_event_parse(struct tep_event *event, struct tep_record *record,
>  			return 0;
>  	}
>  
> +	if (event_ctx->event_pid) {
> +		if (event_ctx->event_pid != tep_data_pid(event->tep, record))
> +			return 0;
> +	}
> +
>  	if (event_ctx->parse_event)
>  		return event_ctx->parse_event(event, record,
>  					      &event_ctx->jlist_head);
> diff --git a/cxl/event_trace.h b/cxl/event_trace.h
> index ec6267202c8b..7f7773b2201f 100644
> --- a/cxl/event_trace.h
> +++ b/cxl/event_trace.h
> @@ -15,6 +15,7 @@ struct event_ctx {
>  	const char *system;
>  	struct list_head jlist_head;
>  	const char *event_name; /* optional */
> +	int event_pid; /* optional */
>  	int (*parse_event)(struct tep_event *event, struct tep_record *record,
>  			   struct list_head *jlist_head); /* optional */
>  };