[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).
> .
>