Re: [PATCH V8 08/14] mmc: core: Add parameter use_blk_mq

[Linus Walleij]

On Fri, Sep 22, 2017 at 3:30 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 21/09/17 12:47, Ulf Hansson wrote:

>> I asume the goal of adding this option is to enable us to move slowly
>> forward. In general that might be a good idea, however for this
>> particular case I am not sure.
>>
>> The main reason is simply that I find it unlikely that people and
>> distributions will actually go in and change the default value, so in
>> the end we will just be adding new code, which isn't really going to
>> be much tested. That's what happened in scsi case.
>
> The argument that no one is going to test anyway so we shouldn't give them
> the opportunity, is not a sustainable vision for the future.  Instead we
> should reach out to relevant stakeholders and get them to do their testing
> with blk-mq first.

We *could* simply invert the option then. Default it to "y" and
only leave it as a debugging aid so that people can set it to
"n" if they want to test with MQ disabled.

This is also simple to revert by a oneliner just removing "default y"
if there are problems with it.

Yours,
Linus Walleij