Re: PREEMPT is messing with everyone

[Bill Davidsen]

Jaswinder Singh wrote:
> On 12/5/06, Michal Schmidt <xschmi00@xxxxxxxxxxxxxxxxxx> wrote:
> > Jaswinder Singh wrote:
> > > Hi,
> > >
> > > preempt stuff SHOULD only stay in #ifdef CONFIG_PREEMP_* , but it is
> > > messing with everyone even though not defined.
> > >
> > > e.g.
> > >
> > > 1. linux-2.6.19/kernel/spinlock.c
> > >
> > > Line 18: #include <linux/preempt.h>
> > >
> > > Line 26:  preempt_disable();
> > >
> > > Line 32:  preempt_disable();
> > >
> > > and so on .
> >
> > Don't worry. These compile into "do { } while (0)" (i.e. nothing) when
> > CONFIG_PREEMPT is not set.
>
> Yes, Compiler will remove it but this looks ugly and confusing.
>
> Why dont we use like this :-

Because it's ugly and confusing.
> #ifdef CONFIG_PREEMPT
> #include <linux/preempt.h>
> #endif
>
> #ifdef CONFIG_PREEMPT
> preempt_disable();
> #endif
>
> #ifdef CONFIG_PREEMPT
> preempt_enable();
> #endif


--
bill davidsen <davidsen@xxxxxxx>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979
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