Re: [PATCH 0/7] ppc: remove cli()/sti() from arch/ppc/*

[Jim Nelson]

Christoph Hellwig wrote:
> On Tue, Jan 04, 2005 at 09:44:06PM -0500, Jim Nelson wrote:
>
> > Brian Gerst wrote:
> >
> >
> > > James Nelson wrote:
> > >
> > >
> > > > This series of patches is to remove the last cli()/sti() function 
> > > > calls in arch/ppc.
> > > >
> > > > These are the only instances in active code that grep could find.
> > >
> > >
> > > Are you sure none of these need real spinlocks instead of just 
> > > disabling interrupts?
> > >
> > > --
> > >               Brian Gerst
> >
> > These are for single-processor systems, mostly evaluation boards and 
> > embedded processors.  I coudn't find any reference to multiprocessor 
> > setups for the processors in question after a peruse of the code or a 
> > quick google on the boards in question.
>
>
> think CONFIG_PREEMPT.  In either case a spinlock becomes
> lock_irq_disable in the !SMP, !PREEMPT case but it documents the
> intention a whole lot better.
>
> Also you're locking only in a single plpace which is a ***BIG*** warning
> sign.  At least look at the other users of the data structure, it's
> extremly likely they'll need locking aswell.

Some of the cli() uses were in shutdown and IRQ setup code, where you'd just need 
to disable interrupts.  There are a few files that will need a more thourough 
going-through, however.

I'll start checking those later.

Jim
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