From: Chao Leng <lengchao@huawei.com>
To: Daniel Wagner <dwagner@suse.de>
Cc: <linux-nvme@lists.infradead.org>,
Sagi Grimberg <sagi@grimberg.me>, <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@fb.com>, Hannes Reinecke <hare@suse.de>,
Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v2] nvme-multipath: Early exit if no path is available
Date: Thu, 28 Jan 2021 17:18:56 +0800 [thread overview]
Message-ID: <69575290-200e-b4a1-4269-c71e4c2cc37b@huawei.com> (raw)
In-Reply-To: <20210128075837.u5u56t23fq5gu6ou@beryllium.lan>
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).
> .
>
next prev parent reply other threads:[~2021-01-28 9:23 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-27 10:30 [PATCH v2] nvme-multipath: Early exit if no path is available Daniel Wagner
2021-01-27 10:34 ` Hannes Reinecke
2021-01-27 16:49 ` Christoph Hellwig
2021-01-28 1:31 ` Chao Leng
2021-01-28 7:58 ` Daniel Wagner
2021-01-28 9:18 ` Chao Leng [this message]
2021-01-28 9:23 ` Hannes Reinecke
2021-01-29 1:18 ` Chao Leng
2021-01-28 9:40 ` Daniel Wagner
2021-01-29 1:23 ` Chao Leng
2021-01-29 1:42 ` Sagi Grimberg
2021-01-29 3:07 ` Chao Leng
2021-01-29 3:30 ` Sagi Grimberg
2021-01-29 3:36 ` Chao Leng
2021-01-29 7:06 ` Hannes Reinecke
[not found] ` <81b22bbf-4dd3-6161-e63a-9699690a4e4f@huawei.com>
[not found] ` <715dd943-0587-be08-2840-e0948cf0bc62@suse.de>
[not found] ` <eb131d8f-f009-42e7-105d-58b84060f0dd@huawei.com>
[not found] ` <ac019690-7f02-d28c-ed58-bfc8c1d48879@suse.de>
2021-02-01 2:16 ` Chao Leng
2021-02-01 7:29 ` Hannes Reinecke
2021-02-01 8:47 ` Chao Leng
2021-02-01 8:57 ` Hannes Reinecke
2021-02-01 9:40 ` Chao Leng
2021-02-01 10:45 ` Hannes Reinecke
2021-02-02 1:12 ` Chao Leng
2021-01-28 1:36 ` Chao Leng
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