[PATCH] nvme: allow lightnvm to have visibility over AER events

[Keith Busch]

Hi Javier,

We currently do have some logic in the core to say which events are
sent to user space for handling and others that are handled internally.
There's currently just two events with kernel specifc handling:
namespace inventory change, and firmware activation.

The example in your patch looks like one of the scenarios envisioned
to be handled by a udev rule. Is that not going to work for you here?

If you do have an event that needs special handling, I think you'd want
to filter that out of the user space notification and invoke the kernel
callback specific to it your event.

On Fri, Apr 13, 2018 at 01:43:00PM +0200, Javier González wrote:
> +static void nvme_aer_handle_work(struct work_struct *work)
> +{
> +	struct nvme_ctrl *ctrl =
> +		container_of(work, struct nvme_ctrl, aer_handle_work);
> +
> +	if (ctrl->aen_result & NVME_AER_NOTICE_LNVM_CHUNK)
> +		nvme_nvm_aer_handle(ctrl);

This 'if' will evaluate to true for _any_ VS AEN result, so this doesn't
look like the right criteria for an LNVM specific.

> +	nvme_async_event(ctrl);
> +}
> +
>  static bool nvme_ctrl_pp_status(struct nvme_ctrl *ctrl)
>  {
>  
> @@ -3362,7 +3378,16 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
>  	default:
>  		dev_warn(ctrl->device, "async event result %08x\n", result);
>  	}
> -	queue_work(nvme_wq, &ctrl->async_event_work);
> +
> +	/* TODO: Create a flag signaling the events that require kernel handling
> +	 * to make this treatment generic
> +	 */
> +	if (result & NVME_AER_NOTICE_LNVM_CHUNK) {
> +		ctrl->aen_result = result;
> +		queue_work(nvme_wq, &ctrl->aer_handle_work);

If this event needs special kernel handling, you should filter it out
in the switch statement above this code and directly invoke the special
callback.

I'm a bit concerned about special handling on a vendor specific code,
though. That could easily collide with another vendor's that has an
entirely different meaning.