[PATCH blktests v3 3/3] nvme: introduce nvmet_target_{setup/cleanup} common code

[Daniel Wagner]

On Fri, Aug 25, 2023 at 06:45:25AM -0700, Bart Van Assche wrote:
> On 8/25/23 00:34, Shinichiro Kawasaki wrote:
> > Recently, you actively cleans up tests/nvme/* (which is great!), and introduced
> > argument parsers in test/nvme/rc. The first one is _nvme_connect_subsys, and the
> > second one is this _nvme_target_setup. It looks for me this is a bash coding
> > style change in blktests, from "don't use optional arguments often" to "use
> > optional arguments aggressively". If we apply this change, we should suppress
> > SC2119. If we keep the old coding style, we should keep on enabling SC2119. What
> > I see here is the style difference between you and Bart.
> > 
> > Now I'm tempted to disable SC2119, and to go with the new coding style...
> > 
> > If I have any misunderstanding, or if anyone has more comments on this, please
> > let me know.
> 
> I don't like the "new style". What is so hard about typing "$@" to pass all function
> arguments to _nvmet_target_setup()? Leaving out "$@" makes it much harder than
> necessary to figure out the intent of the code author - not passing any arguments
> or passing all caller arguments implicitly.

Because "$@" is just not correct. Also by using defaults we really see
where the test is special.

Let's look at this here:

 _create_nvmet_subsystem "${def_subsysnqn}" "${def_file_path}"

Both arguments are default values and could just be left out. It makes
reading the code way simpler,

 _create_nvmet_subsystem

Another example, if setup a default target

 _nvmet_target_setup

and if we want to enable the auth code:

 _nvmet_target_setup --ctrlkey "${ctrlkey}" --hostkey "${hostkey}"

and that's all. You can easily see what's is different from the default
values.

The "old" style is expecting that the caller gets the number of
arguments and position correct:

 _create_nvmet_host "${def_subsysnqn}" "${def_hostnqn}" "${hostkey}" "${ctrlkey}"

And this isn't always the case. I already fixed a couple of bugs where
the test got the order wrong.