[dm-devel] [PATCH] dm-mpath: requeue I/O during pg_init

[Alasdair G Kergon]

On Tue, Oct 01, 2013 at 11:49:56AM +0200, Hannes Reinecke wrote:
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -390,7 +390,11 @@ static int map_io(struct multipath *m, struct request *clone,
>  	if (was_queued)
>  		m->queue_size--;
>  
> -	if ((pgpath && m->queue_io) ||
> +	if (m->pg_init_required) {
> +		if (!m->pg_init_in_progress)
> +			queue_work(kmultipathd, &m->process_queued_ios);
> +		r = DM_MAPIO_REQUEUE;
> +	} else if ((pgpath && m->queue_io) ||
>  	    (!pgpath && m->queue_if_no_path)) {
>  		/* Queue for the daemon to resubmit */
>  		list_add_tail(&clone->queuelist, &m->queued_ios);

This sequence if...else if... is becoming more and more unreadable!
- Two cases now return REQUEUE; two cases now queue_work().

If it really can't be simplified, could we at least add some explanatory
comments inline?

Alasdair