Re: [PATCH 1/2] nvme: keep transport module referenced while head node is open

[Nilay Shroff <nilay@linux.ibm.com>]

Hi Christoph,

A gentle ping on this one... Do you have any further comments on this?

Thanks,
--Nilay

On 9/2/26 7:57 PM, Nilay Shroff wrote:
> 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