Re: [PATCH v2] nvme-multipath: Early exit if no path is available

[Chao Leng]

On 2021/1/28 15:58, Daniel Wagner wrote:
> On Thu, Jan 28, 2021 at 09:31:30AM +0800, Chao Leng wrote:
> > > --- a/drivers/nvme/host/multipath.c
> > > +++ b/drivers/nvme/host/multipath.c
> > > @@ -221,7 +221,7 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
> > >    	}
> > >    	for (ns = nvme_next_ns(head, old);
> > > -	     ns != old;
> > > +	     ns && ns != old;
> > nvme_round_robin_path just be called when !"old".
> > nvme_next_ns should not return NULL when !"old".
> > It seems unnecessary to add checking "ns".
>
> The problem is when we enter nvme_round_robin_path() and there is no
> path available. In this case the initialization ns = nvme_next_ns(head,
> old) could return a NULL pointer."old" should not be NULL, so there is at least one path that is "old".
It is impossible to return NULL for nvme_next_ns(head, old).
> .