From: Christoph Hellwig <hch@lst.de>
To: Nilay Shroff <nilay@linux.ibm.com>
Cc: linux-nvme@lists.infradead.org, kbusch@kernel.org,
sagi@grimberg.me, hch@lst.de, axboe@fb.com,
john.g.garry@oracle.com, wenxiong@linux.ibm.com,
gjoyce@linux.ibm.com
Subject: Re: [PATCH 1/2] nvme: keep transport module referenced while head node is open
Date: Wed, 2 Sep 2026 15:31:04 +0200 [thread overview]
Message-ID: <20260902133104.GA20945@lst.de> (raw)
In-Reply-To: <20260831152006.819471-2-nilay@linux.ibm.com>
On Mon, Aug 31, 2026 at 08:49:54PM +0530, Nilay Shroff wrote:
> When a user opens an NVMe multipath head node, we take a reference to
> the head node, but this does not prevent the transport module backing
> its paths from being unloaded. This can result in the multipath head
> remaining open while its underlying transport module is unloaded.
Which makes sense. Different paths can use different transports, but
even when all paths go away, the head can stick around.
> Fix this by taking a reference to the transport module for each active
> path when the multipath head node is opened. Keep track of the number
> of active head node openers so that dynamically added paths acquire the
> same number of transport module references.
I'm not sure this is correct. Unloading the layer below should be
just fine.
What practical problem do you want to solve with this?
next prev parent reply other threads:[~2026-09-02 13:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-31 15:19 [PATCH 0/2] nvme: add reference counting for transport modules Nilay Shroff
2026-08-31 15:19 ` [PATCH 1/2] nvme: keep transport module referenced while head node is open Nilay Shroff
2026-09-01 16:39 ` Keith Busch
2026-09-02 4:55 ` Nilay Shroff
2026-09-02 0:20 ` Wen Xiong
2026-09-02 13:31 ` Christoph Hellwig [this message]
2026-09-02 14:09 ` Nilay Shroff
2026-09-02 14:13 ` Christoph Hellwig
2026-09-02 14:25 ` Keith Busch
2026-09-02 14:27 ` Nilay Shroff
2026-09-13 14:03 ` Nilay Shroff
2026-08-31 15:19 ` [PATCH 2/2] nvme: add context annotation for nvme_ns_head::nr_openers Nilay Shroff
2026-09-01 8:14 ` [PATCH 0/2] nvme: add reference counting for transport modules John Garry
2026-09-01 9:47 ` Nilay Shroff
2026-09-01 10:14 ` John Garry
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