Nouveau - Jan 2022 - [PATCH 0/3] lib/string_helpers: Add a few string helpers

On Wed, 19 Jan 2022, Petr Mladek <pmladek at suse.com>
wrote:
> On Tue 2022-01-18 23:24:47, Lucas De Marchi wrote:
>> Add some helpers under lib/string_helpers.h so they can be used
>> throughout the kernel. When I started doing this there were 2 other
>> previous attempts I know of, not counting the iterations each of them
>> had:
>> 
>> 1) https://lore.kernel.org/all/20191023131308.9420-1-jani.nikula at
intel.com/
>> 2) https://lore.kernel.org/all/20210215142137.64476-1-andriy.shevchenko
at linux.intel.com/#t
>> 
>> Going through the comments I tried to find some common ground and
>> justification for what is in here, addressing some of the concerns
>> raised.
>> 
>> d. This doesn't bring onoff() helper as there are some places in
the
>>    kernel with onoff as variable - another name is probably needed for
>>    this function in order not to shadow the variable, or those
variables
>>    could be renamed.  Or if people wanting  <someprefix>
>>    try to find a short one
>
> I would call it str_on_off().
>
> And I would actually suggest to use the same style also for
> the other helpers.
>
> The "str_" prefix would make it clear that it is something with
> string. There are other <prefix>_on_off() that affect some
> functionality, e.g. mute_led_on_off(), e1000_vlan_filter_on_off().
>
> The dash '_' would significantly help to parse the name. yesno()
and
> onoff() are nicely short and kind of acceptable. But
"enabledisable()"
> is a puzzle.
>
> IMHO, str_yes_no(), str_on_off(), str_enable_disable() are a good
> compromise.
>
> The main motivation should be code readability. You write the
> code once. But many people will read it many times. Open coding
> is sometimes better than misleading macro names.
>
> That said, I do not want to block this patchset. If others like
> it... ;-)
I don't mind the names either way. Adding the prefix and dashes is
helpful in that it's possible to add the functions first and convert
users at leisure, though with a bunch of churn, while using names that
collide with existing ones requires the changes to happen in one go.

What I do mind is grinding this series to a halt once again. I sent a
handful of versions of this three years ago, with inconclusive
bikeshedding back and forth, eventually threw my hands up in disgust,
and walked away.
>
>
>> e. One alternative to all of this suggested by Christian K?nig
>>    (43456ba7-c372-84cc-4949-dcb817188e21 at amd.com) would be to add a
>>    printk format. But besides the comment, he also seemed to like
>>    the common function. This brought the argument from others that the
>>    simple yesno()/enabledisable() already used in the code is easier to
>>    remember and use than e.g. %py[DOY]
>
> Thanks for not going this way :-)
>
>> Last patch also has some additional conversion of open coded cases. I
>> preferred starting with drm/ since this is "closer to home".
>> 
>> I hope this is a good summary of the previous attempts and a way we can
>> move forward.
>> 
>> Andrew Morton, Petr Mladek, Andy Shevchenko: if this is accepted, my
>> proposal is to take first 2 patches either through mm tree or maybe
>> vsprintf. Last patch can be taken later through drm.
>
> I agree with Andy that it should go via drm tree. It would make it
> easier to handle potential conflicts.
>
> Just in case, you decide to go with str_yes_no() or something similar.
> Mass changes are typically done at the end on the merge window.
> The best solution is when it can be done by a script.
>
> Best Regards,
> Petr
-- 
Jani Nikula, Intel Open Source Graphics Center

On Wed, Jan 19, 2022 at 04:16:12PM +0200, Jani Nikula
wrote:
> On Wed, 19 Jan 2022, Petr Mladek <pmladek at suse.com> wrote:
> > On Tue 2022-01-18 23:24:47, Lucas De Marchi wrote:
> >> Add some helpers under lib/string_helpers.h so they can be used
> >> throughout the kernel. When I started doing this there were 2
other
> >> previous attempts I know of, not counting the iterations each of
them
> >> had:
> >> 
> >> 1) https://lore.kernel.org/all/20191023131308.9420-1-jani.nikula
at intel.com/
> >> 2)
https://lore.kernel.org/all/20210215142137.64476-1-andriy.shevchenko at
linux.intel.com/#t
> >> 
> >> Going through the comments I tried to find some common ground and
> >> justification for what is in here, addressing some of the concerns
> >> raised.
> >> 
> >> d. This doesn't bring onoff() helper as there are some places
in the
> >>    kernel with onoff as variable - another name is probably needed
for
> >>    this function in order not to shadow the variable, or those
variables
> >>    could be renamed.  Or if people wanting  <someprefix>
> >>    try to find a short one
> >
> > I would call it str_on_off().
> >
> > And I would actually suggest to use the same style also for
> > the other helpers.
> >
> > The "str_" prefix would make it clear that it is something
with
> > string. There are other <prefix>_on_off() that affect some
> > functionality, e.g. mute_led_on_off(), e1000_vlan_filter_on_off().
> >
> > The dash '_' would significantly help to parse the name.
yesno() and
> > onoff() are nicely short and kind of acceptable. But
"enabledisable()"
> > is a puzzle.
> >
> > IMHO, str_yes_no(), str_on_off(), str_enable_disable() are a good
> > compromise.
> >
> > The main motivation should be code readability. You write the
> > code once. But many people will read it many times. Open coding
> > is sometimes better than misleading macro names.
> >
> > That said, I do not want to block this patchset. If others like
> > it... ;-)
> 
> I don't mind the names either way. Adding the prefix and dashes is
> helpful in that it's possible to add the functions first and convert
> users at leisure, though with a bunch of churn, while using names that
> collide with existing ones requires the changes to happen in one go.
> 
> What I do mind is grinding this series to a halt once again. I sent a
> handful of versions of this three years ago, with inconclusive
> bikeshedding back and forth, eventually threw my hands up in disgust,
> and walked away.
Yeah we can sed this anytime later we want to, but we need to get the foot
in the door. There's also a pile more of these all over.

Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>

on the series, maybe it helps? And yes let's merge this through drm-misc.
-Daniel
> 
> >
> >
> >> e. One alternative to all of this suggested by Christian K?nig
> >>    (43456ba7-c372-84cc-4949-dcb817188e21 at amd.com) would be to
add a
> >>    printk format. But besides the comment, he also seemed to like
> >>    the common function. This brought the argument from others that
the
> >>    simple yesno()/enabledisable() already used in the code is
easier to
> >>    remember and use than e.g. %py[DOY]
> >
> > Thanks for not going this way :-)
> >
> >> Last patch also has some additional conversion of open coded
cases. I
> >> preferred starting with drm/ since this is "closer to
home".
> >> 
> >> I hope this is a good summary of the previous attempts and a way
we can
> >> move forward.
> >> 
> >> Andrew Morton, Petr Mladek, Andy Shevchenko: if this is accepted,
my
> >> proposal is to take first 2 patches either through mm tree or
maybe
> >> vsprintf. Last patch can be taken later through drm.
> >
> > I agree with Andy that it should go via drm tree. It would make it
> > easier to handle potential conflicts.
> >
> > Just in case, you decide to go with str_yes_no() or something similar.
> > Mass changes are typically done at the end on the merge window.
> > The best solution is when it can be done by a script.
> >
> > Best Regards,
> > Petr
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

On Wed 2022-01-19 16:16:12, Jani Nikula wrote:
> On Wed, 19 Jan 2022, Petr Mladek <pmladek at suse.com> wrote:
> > On Tue 2022-01-18 23:24:47, Lucas De Marchi wrote:
> >> d. This doesn't bring onoff() helper as there are some places
in the
> >>    kernel with onoff as variable - another name is probably needed
for
> >>    this function in order not to shadow the variable, or those
variables
> >>    could be renamed.  Or if people wanting  <someprefix>
> >>    try to find a short one
> >
> > I would call it str_on_off().
> >
> > And I would actually suggest to use the same style also for
> > the other helpers.
> >
> > The "str_" prefix would make it clear that it is something
with
> > string. There are other <prefix>_on_off() that affect some
> > functionality, e.g. mute_led_on_off(), e1000_vlan_filter_on_off().
> >
> > The dash '_' would significantly help to parse the name.
yesno() and
> > onoff() are nicely short and kind of acceptable. But
"enabledisable()"
> > is a puzzle.
> >
> > IMHO, str_yes_no(), str_on_off(), str_enable_disable() are a good
> > compromise.
> >
> > The main motivation should be code readability. You write the
> > code once. But many people will read it many times. Open coding
> > is sometimes better than misleading macro names.
> >
> > That said, I do not want to block this patchset. If others like
> > it... ;-)
> 
> I don't mind the names either way. Adding the prefix and dashes is
> helpful in that it's possible to add the functions first and convert
> users at leisure, though with a bunch of churn, while using names that
> collide with existing ones requires the changes to happen in one go.
It is also possible to support both notations at the beginning.
And convert the existing users in the 2nd step.
> What I do mind is grinding this series to a halt once again. I sent a
> handful of versions of this three years ago, with inconclusive
> bikeshedding back and forth, eventually threw my hands up in disgust,
> and walked away.
Yeah, and I am sorry for bikeshedding. Honestly, I do not know what is
better. This is why I do not want to block this series when others
like this.

My main motivation is to point out that:

    enabledisable(enable)

might be, for some people, more eye bleeding than

    enable ? "enable" : "disable"


The problem is not that visible with yesno() and onoff(). But as you said,
onoff() confliscts with variable names. And enabledisable() sucks.
As a result, there is a non-trivial risk of two mass changes:

now:

- contition ? "yes" : "no"
+ yesno(condition)

a few moths later:

- yesno(condition)
+ str_yes_no(condition)


Best Regards,
Petr

...
> Yeah, and I am sorry for bikeshedding. Honestly, I do not know what is
> better. This is why I do not want to block this series when others
> like this.
> 
> My main motivation is to point out that:
> 
>     enabledisable(enable)
> 
> might be, for some people, more eye bleeding than
> 
>     enable ? "enable" : "disable"
Indeed - you need to look the former up, wasting brain time.
> The problem is not that visible with yesno() and onoff(). But as you said,
> onoff() confliscts with variable names. And enabledisable() sucks.
> As a result, there is a non-trivial risk of two mass changes:
> 
> now:
> 
> - contition ? "yes" : "no"
> + yesno(condition)
> 
> a few moths later:
> 
> - yesno(condition)
> + str_yes_no(condition)
Followed by:
- str_yes_no(x)
+ no_yes_str(x)

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT,
UK
Registration No: 1397386 (Wales)

On Thu, 20 Jan 2022, Petr Mladek <pmladek at suse.com>
wrote:
> On Wed 2022-01-19 16:16:12, Jani Nikula wrote:
>> On Wed, 19 Jan 2022, Petr Mladek <pmladek at suse.com> wrote:
>> > On Tue 2022-01-18 23:24:47, Lucas De Marchi wrote:
>> >> d. This doesn't bring onoff() helper as there are some
places in the
>> >>    kernel with onoff as variable - another name is probably
needed for
>> >>    this function in order not to shadow the variable, or those
variables
>> >>    could be renamed.  Or if people wanting  <someprefix>
>> >>    try to find a short one
>> >
>> > I would call it str_on_off().
>> >
>> > And I would actually suggest to use the same style also for
>> > the other helpers.
>> >
>> > The "str_" prefix would make it clear that it is
something with
>> > string. There are other <prefix>_on_off() that affect some
>> > functionality, e.g. mute_led_on_off(), e1000_vlan_filter_on_off().
>> >
>> > The dash '_' would significantly help to parse the name.
yesno() and
>> > onoff() are nicely short and kind of acceptable. But
"enabledisable()"
>> > is a puzzle.
>> >
>> > IMHO, str_yes_no(), str_on_off(), str_enable_disable() are a good
>> > compromise.
>> >
>> > The main motivation should be code readability. You write the
>> > code once. But many people will read it many times. Open coding
>> > is sometimes better than misleading macro names.
>> >
>> > That said, I do not want to block this patchset. If others like
>> > it... ;-)
>> 
>> I don't mind the names either way. Adding the prefix and dashes is
>> helpful in that it's possible to add the functions first and
convert
>> users at leisure, though with a bunch of churn, while using names that
>> collide with existing ones requires the changes to happen in one go.
>
> It is also possible to support both notations at the beginning.
> And convert the existing users in the 2nd step.
>
>> What I do mind is grinding this series to a halt once again. I sent a
>> handful of versions of this three years ago, with inconclusive
>> bikeshedding back and forth, eventually threw my hands up in disgust,
>> and walked away.
>
> Yeah, and I am sorry for bikeshedding. Honestly, I do not know what is
> better. This is why I do not want to block this series when others
> like this.
>
> My main motivation is to point out that:
>
>     enabledisable(enable)
>
> might be, for some people, more eye bleeding than
>
>     enable ? "enable" : "disable"
>
>
> The problem is not that visible with yesno() and onoff(). But as you said,
> onoff() confliscts with variable names. And enabledisable() sucks.
> As a result, there is a non-trivial risk of two mass changes:
My point is, in the past three years we could have churned through more
than two mass renames just fine, if needed, *if* we had just managed to
merge something for a start!

BR,
Jani.
>
> now:
>
> - contition ? "yes" : "no"
> + yesno(condition)
>
> a few moths later:
>
> - yesno(condition)
> + str_yes_no(condition)
>
>
> Best Regards,
> Petr
-- 
Jani Nikula, Intel Open Source Graphics Center