Date:   Tue, 14 Dec 2021 08:29:59 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Bart Van Assche <bvanassche@acm.org>
Cc:     Eric Biggers <ebiggers@kernel.org>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        linux-scsi@vger.kernel.org, linux-mmc@vger.kernel.org,
        Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH v3 3/3] blk-crypto: show crypto capabilities in sysfs
Message-ID: <YbhH9z/hVg+RsWhL@kroah.com>
References: <20211208013534.136590-1-ebiggers@kernel.org>
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On Mon, Dec 13, 2021 at 09:04:29PM -0800, Bart Van Assche wrote:
> On 12/11/21 02:50, Greg Kroah-Hartman wrote:
> > On Fri, Dec 10, 2021 at 09:29:41AM -0800, Bart Van Assche wrote:
> > > (b) No other block layer sysfs attribute follows this encoding scheme.
> > 
> > Then follow what they do.  Do they have multiple values in a single
> > file?  If so, they are broken and we should change that.
> 
> Hi Greg,
> 
> The only other block layer sysfs attribute I know of that reports multiple
> values is the queue/scheduler attribute. Here is an example of the output
> that can be produced by reading that attribute:
> 
> # cat /sys/block/sda/queue/scheduler
> [mq-deadline] kyber bfq none

That's fine, there is no problem there.

That output is the "correct" way to show a list of options and the one
that is currently selected in a sysfs file as I thought I said earlier
in this thread.

> I don't think that changing the behavior of that attribute is an option
> because that would break existing user space software, e.g. the
> https://github.com/osandov/blktests/ test suite.

Very true, do not change this file format.

thanks,

greg k-h