From: Nilay Shroff <nilay@linux.ibm.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-nvme@lists.infradead.org, kbusch@kernel.org,
sagi@grimberg.me, 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 19:57:47 +0530 [thread overview]
Message-ID: <61165430-a724-40d3-a00d-2cbe1ea656b0@linux.ibm.com> (raw)
In-Reply-To: <20260902141347.GA24385@lst.de>
On 9/2/26 7:43 PM, Christoph Hellwig wrote:
> On Wed, Sep 02, 2026 at 07:39:32PM +0530, Nilay Shroff wrote:
>> So the practical problem is that an open multipath head can continue to
>> be used after its underlying transport module has been unloaded. The
>> proposed change keeps the transport module referenced while the head
>> node is open, preventing the module from being unloaded in this
>> scenario.
>
> But why do you unload it in the first place?
>
Well, in my view, unloading a module while it is not in use should be a legitimate operation.
In the example shown earlier, the NVMe transport module is still being
used by the open multipath head. Shouldn't we explicitly reflect that by
incrementing its module refcount? We don't explicitly unload the module
as part of normal NVMe operation, but in theory I think the transport module
should remain referenced for as long as it is being used. That would also
prohibit user from unloading module by mistake.
Thanks,
--Nilay
next prev parent reply other threads:[~2026-09-02 14:28 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
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 [this message]
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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