Re: [PATCH v2] nvme-multipath: Early exit if no path is available
From: Hannes Reinecke <hare@suse.de>
Date: 2021-01-28 09:32:01
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lkml
On 1/28/21 10:18 AM, Chao Leng wrote:
On 2021/1/28 15:58, Daniel Wagner wrote:quoted
On Thu, Jan 28, 2021 at 09:31:30AM +0800, Chao Leng wrote:quoted
quoted
--- 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).
No. list_next_or_null_rcu()/list_first_or_null_rcu() will return NULL when then end of the list is reached. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme