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SubjectRe: [PATCH v2] printk: ignore recursion_bug flag in HW error handle process
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On Thu, 2012-05-24 at 15:56 -0700, Andrew Morton wrote:
> On Thu, 24 May 2012 08:11:45 +0200
> Borislav Petkov <bp@alien8.de> wrote:
>
> > > +/* HW error handle status helpers */
> > > +extern atomic_t hw_error;
> > > +static inline void hw_error_enter(void)
> > > +{
> > > + atomic_inc(&hw_error);
> > > +}
> > > +
> > > +static inline void hw_error_exit(void)
> > > +{
> > > + atomic_dec(&hw_error);
> > > +}
> > > +
> > > +static inline int in_hw_error(void)
> > > +{
> > > + return atomic_read(&hw_error);
> > > +}
> >
> > Shouldn't those be generic empty functions and each arch implement their
> > own with the stuff they want to do on the respective architecture when
> > they get a hardware error?
>
> This code needs documentation.
>
> Specifically, it should clearly explain (and hence define) what a
> "hardware error" *is*, and for what purpose this code exists.
>
> Because as it stands, this interface is hopelessly vague. Once one
> sees that it is *specifically* used for handling mce within a printk,
> it all makes sense.
>
> And with that understanding comes the realisation that the interface is
> poorly named. It will not be used for any purpose other than adjusting
> printk() behavior so it should mention printk() in its name and in its
> comments and probably it should all be moved into printk.h.
>
> Futhermore, this code is not really related to MCE or hardware or
> anything else. It is simply a way in which callers can suppress
> printk()'s recursion check. Callers are free to use it for reasons
> other than "hardware errors".
>
> And once all that is done, and this interface becomes part of printk()
> then no, there is no need to add per-arch hooks. An arch can call into
> printk_recursion_check_disable() and printk_recursion_chack_enable() -
> nice and simple.
>
>
> IOW, the title of this patch should be
>
> [patch 1/2] printk: add interface for disabling recursion check
> [patch 2/2] x86 mce: use new printk recursion disabling interface
Andrew,

Thanks for the detailed comment. It's more reasonable to bind it to printk.
We would follow it to create new patches.

Yanmin




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