lkml.org 
[lkml]   [2020]   [Apr]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [RFC 0/6] Regressions for "imply" behavior change
On Wed, Apr 8, 2020 at 10:38 PM Nicolas Pitre <nico@fluxnic.net> wrote:
> On Wed, 8 Apr 2020, Arnd Bergmann wrote:
> > I have created workarounds for the Kconfig files, which now stop using
> > imply and do something else in each case. I don't know whether there was
> > a bug in the kconfig changes that has led to allowing configurations that
> > were not meant to be legal even with the new semantics, or if the Kconfig
> > files have simply become incorrect now and the tool works as expected.
>
> In most cases it is the code that has to be fixed. It typically does:
>
> if (IS_ENABLED(CONFIG_FOO))
> foo_init();
>
> Where it should rather do:
>
> if (IS_REACHABLE(CONFIG_FOO))
> foo_init();
>
> A couple of such patches have been produced and queued in their
> respective trees already.

I try to use IS_REACHABLE() only as a last resort, as it tends to
confuse users when a subsystem is built as a module and already
loaded but something relying on that subsystem does not use it.

In the six patches I made, I had to use IS_REACHABLE() once,
for the others I tended to use a Kconfig dependency like

'depends on FOO || FOO=n'

which avoids the case that IS_REACHABLE() works around badly.

I did come up with the IS_REACHABLE() macro originally, but that
doesn't mean I think it's a good idea to use it liberally ;-)

Arnd

\
 
 \ /
  Last update: 2020-04-08 22:50    [W:0.167 / U:0.192 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site