Messages in this thread | | | Date | Mon, 19 Jan 2004 11:42:09 +0530 | From | Prashanth T <> | Subject | Re: [PATCH] rwlock_is_locked undefined for UP systems |
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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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