From: Sagi Grimberg <sagi@grimberg.me>
To: Keith Busch <kbusch@kernel.org>, Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>,
linux-nvme@lists.infradead.org, Keith Busch <keith.busch@wdc.com>
Subject: Re: [PATCH 2/2] nvme: add 'queue_if_no_path' semantics
Date: Fri, 5 Mar 2021 12:11:03 -0800 [thread overview]
Message-ID: <68ca5a63-e6e3-be5a-4b60-bd9db52ac9c1@grimberg.me> (raw)
In-Reply-To: <20201006174100.GA959043@dhcp-10-100-145-180.wdl.wdc.com>
> I think what you're showing is a problem for everyone, including
> fabrics. The namespace was attached to the previously existing
> subsystem, nvme1, but we didn't find the previously existing "head" to
> reattach the namespace.
>
> I just threw the below together very hastily, so I'm sure there's
> something wrong with it, but just to capture what's wrong with the
> current code:
>
> ---
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 3833584b5cee..0b3bbbe6d1e8 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -3897,8 +3897,6 @@ static void nvme_ns_remove(struct nvme_ns *ns)
>
> mutex_lock(&ns->ctrl->subsys->lock);
> list_del_rcu(&ns->siblings);
> - if (list_empty(&ns->head->list))
> - list_del_init(&ns->head->entry);
Not removing it ever from the head->list?
> mutex_unlock(&ns->ctrl->subsys->lock);
>
> synchronize_rcu(); /* guarantee not available in head->list */
> --
This is a problem. beacuse if you don't remove the ns from the
head->list nothing prevents it from being re-selected as the
current_path after we synchronize the srcu, although it is going away...
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next prev parent reply other threads:[~2021-03-05 20:11 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 12:44 [RFC PATCHv3 0/2] nvme: queue_if_no_path functionality Hannes Reinecke
2020-10-05 12:44 ` [PATCH 1/2] nvme-mpath: delete disk after last connection Hannes Reinecke
2020-10-05 12:50 ` Christoph Hellwig
2021-03-05 20:06 ` Sagi Grimberg
2021-03-04 14:34 ` Daniel Wagner
2020-10-05 12:45 ` [PATCH 2/2] nvme: add 'queue_if_no_path' semantics Hannes Reinecke
2020-10-05 12:52 ` Christoph Hellwig
2020-10-06 5:48 ` Hannes Reinecke
2020-10-06 7:51 ` Christoph Hellwig
2020-10-06 8:07 ` Hannes Reinecke
2020-10-06 8:27 ` Christoph Hellwig
2020-10-06 8:29 ` Hannes Reinecke
2020-10-06 8:39 ` Christoph Hellwig
2020-10-06 13:30 ` Hannes Reinecke
2020-10-06 13:45 ` Hannes Reinecke
2021-03-05 20:31 ` Sagi Grimberg
2021-03-08 13:17 ` Hannes Reinecke
2021-03-15 17:21 ` Sagi Grimberg
2020-10-06 17:41 ` Keith Busch
2021-03-05 20:11 ` Sagi Grimberg [this message]
2021-03-11 12:41 ` Hannes Reinecke
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