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To:     Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
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Cc:     Sagi Grimberg <sagi@grimberg.me>,
        Stephen Bates <sbates@raithlin.com>
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From:   Logan Gunthorpe <logang@deltatee.com>
Message-ID: <517a5fd9-50eb-eb5e-5911-093dc5d1a759@deltatee.com>
Date:   Tue, 6 Oct 2020 18:10:16 -0600
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Subject: Re: [PATCH blktests v2 04/11] nvme: Search for specific subsysnqn in
 _find_nvme_loop_dev
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On 2020-10-06 5:55 p.m., Chaitanya Kulkarni wrote:
> On 9/30/20 11:54, Logan Gunthorpe wrote:
>> This ensures we find the correct nvme loop device if others exist on a
>> given system (which is generally not expected on test systems).
>>
>> Additionally, this will be required in the upcomming test nvme/037 which
>> will have controllers racing with ones being destroyed.
>>
>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> 
> If I create a passthru testcase with :-
> 
> 1. Create nvme-loop based nvme ctrl backed by null_blk say /dev/nvme1
> 
> 2. Create a nvme-loop based passthru ctrl backed by /dev/nvme1 say nvme2.
> 
> 
> With this patch or this series will I be able to write the testcase ?

This patch helps with that but other helpers introduced in this series
would require minor changes.

As far as I can see, you'd only have to adjust _create_nvmet_passthru()
to take an optional argument because, presently, it always uses
$_test_dev_nvme_ctrl for the backing device.

This can easily be done if and when someone writes such a test.

However, I'm not even sure right now if that test would pass in the
kernel as is -- it seems like an odd thing to do.

Logan