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Subject: Re: [PATCH v2 1/4] null_blk: do not fail the module load with zero
 devices
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        krisman@collabora.com
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From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <7c0f4547-4193-bd3e-85c6-d950a004ac46@acm.org>
Date:   Fri, 13 Sep 2019 15:17:53 -0700
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On 9/13/19 3:02 PM, André Almeida wrote:
> The module load should fail only if there is something wrong with the
> configuration or if an error prevents it to work properly. The module
> should be able to be loaded with (nr_device == 0), since it will not
> trigger errors or be in malfunction state. Preventing loading with zero
> devices also breaks applications that configures this module using
> configfs API. Remove the nr_device check to fix this.

I just noticed that this patch is necessary to unbreak blktests. The srp 
tests fail as follows with Jens' for-next branch:

modprobe: ERROR: could not insert 'null_blk': Invalid argument

I think that error is triggered by the following statement in 
common/multipath-over-rdma:

     modprobe null_blk nr_devices=0 || return $?

Bart.