Re: [PATCH] rwlock_is_locked undefined for UP systems

[Prashanth T]

ok....I understand that rwlock_is_locked( ) is to be protected by
CONFIG_SMP.  But I was tempted when I saw spin_is_locked( )
to be returning zero for !SMP in include/linux/spinlock.h . 
Am I seeing something wrong here?

Christoph Hellwig wrote:

> On Fri, Jan 16, 2004 at 07:15:11PM +0530, Prashanth T wrote:
>  
>
> > Hi,
> >    I had to use rwlock_is_locked( ) with linux2.6 for kdb and noticed that
> > this routine to be undefined for UP.  I have attached the patch for 2.6.1
> > below to return 0 for rwlock_is_locked( ) on UP systems.
> > Please let me know.
> >    
>
> we don't implement spin_is_locked on UP either because there's no really
> usefull return value.  The lock will never be taken on !SMP && !PREEMPT,
> but OTOH it's also not needed, so any assert on will give false results.
> And the assert is probably the only thing that the _is_locked routines
> could used for sanely.
>
>
>  

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