linux-kernel - Re: [PATCH blktests v2 2/2] nvme-rc: Cleanup fc resource before module unloading

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Date:   Wed, 19 Apr 2023 13:45:47 +0300
From:   Sagi Grimberg <sagi@...mberg.me>
To:     Daniel Wagner <dwagner@...e.de>
Cc:     linux-nvme@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-block@...r.kernel.org, Chaitanya Kulkarni <kch@...dia.com>,
        Shin'ichiro Kawasaki <shinichiro@...tmail.com>
Subject: Re: [PATCH blktests v2 2/2] nvme-rc: Cleanup fc resource before
 module unloading


>>> Before we unload the module we should cleanup the fc resources first,
>>> basically reorder the shutdown sequence to be in reverse order of the
>>> setup path.
>>
>> If this triggers a bug, then I think it is a good idea to have a
>> dedicated test that reproduces it if we are changing the default
>> behavior.
> 
> Right, though I would like to tackle one problem after the other, first get fc
> working with the 'correct' order.
> 
>>> While at it also update the rdma stop_soft_rdma before the module
>>> unloading for the same reasoning.
>>
>> Why? it creates the wrong reverse ordering.
>>
>> 1. setup soft-rdma
>> 2. setup nvme-rdma
>>
>> 2. teardown nvme-rdma
>> 1. teardown soft-rdma
>>
>> I don't think we need this change. I mean it is a good test
>> to have that the rdma device goes away underneath nvme-rdma
>> but it is good for a dedicated test.
> 
> I was woried about this setup sequence here:
> 
> 	modprobe -q nvme-"${nvme_trtype}"
> 	if [[ "${nvme_trtype}" == "rdma" ]]; then
> 		start_soft_rdma
> 
> The module is loaded before start_soft_rdma is started, thus I thought we should
> do the reverse, first call stop_soft_rdma and the unload the module.

They should be unrelated. the safe route is to first remove the uld and
then the device.