Messages in this thread | | | Date | Mon, 8 Apr 2013 17:36:14 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] locking: remove three unused Kconfig symbols |
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* Paul Bolle <pebolle@tiscali.nl> wrote:
> On Mon, 2013-04-08 at 17:16 +0200, Ingo Molnar wrote: > > * Paul Bolle <pebolle@tiscali.nl> wrote: > > > The Kconfig symbols ARCH_INLINE_READ_UNLOCK_IRQ, > > > ARCH_INLINE_SPIN_UNLOCK_IRQ, and ARCH_INLINE_WRITE_UNLOCK_IRQ were added > > > in v2.6.33, but have never actually been used. It is safe to remove > > > these. > > > > > Erm, if you look at the code in question you'll see that they are unused I think > > due to a bug: > > > > config INLINE_READ_UNLOCK_IRQ > > def_bool y > > depends on !PREEMPT || ARCH_INLINE_READ_UNLOCK_BH > > > > Shouldn't that depend on ARCH_INLINE_READ_UNLOCK_IRQ? > > > > Similarly for the others. > > Yes, that seems correct. I must admit that I didn't spot that > possibility, but then again this Kconfig file is near unreadable (too > much repetition for human readers).
Yeah, Kconfig isn't a very sophisticated language - it's the COBOL of config languages.
> Would you have any idea why this problem wasn't noticed in 16 (!) releases? > Fedora 17, which I did this patch on, has Kconfig symbolk PREEMPT not set. Is it > perhaps commit to not enable that option?
AFAICS it's a latent bug: it can only be noticed if these switches are set to different values by an arch - but the defaults and s390 (the two main cases) never do that.
So it's not causing any runtime problems today - but should be fixed nevertheless, now that you noticed it! :-)
Thanks,
Ingo
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