On Mon, Dec 13, 2021 at 09:04:29PM -0800, Bart Van Assche wrote:

On 12/11/21 02:50, Greg Kroah-Hartman wrote:

quoted

On Fri, Dec 10, 2021 at 09:29:41AM -0800, Bart Van Assche wrote:

quoted

(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