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SubjectRe: question on spinlocks
Oliver Neukum wrote:
>
> Am Montag, 2. September 2002 00:09 schrieb Thunder from the hill:
> > Hi,
> >
> > On Mon, 2 Sep 2002, Oliver Neukum wrote:
> > > > > No; spin_lock_irqsave/spin_unlock_irqrestore and
> > > > > spin_lock/spin_unlock have to be used in matching pairs.
> > > >
> > > > If it was his least problem! He'll run straight into a "schedule
> > > > w/IRQs disabled" bug.
> > >
> > > OK, how do I drop an irqsave spinlock if I don't have flags?
> >
> > IMHO you might even ask "How do I start a car when I don't have the
> > keys?"
>
> Break off the lock, touch some cables ... ;-)
>
> > You might find a way, but it's not desired. Are you sure you want to
> > reschedule in an interrupt handler? If it's none, are you sure you want
> > to disable interrupts?
>
> I am not in an interrupt handler. It's not my fault that the scsi layer
> calls queuecommand with a spinlock held. But I need to sleep,
> I have to get rid of that spinlock's effects. If possible I even want
> interrupts to be enabled.

I don't know scsi, but if the coder decided that the lock
and irq were needed, I suspect that messing with them will
get you in big trouble. I think you need to rethink this
thing at the scsi layer...

-g
>
> Regards
> Oliver
>
> -
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--
George Anzinger george@mvista.com
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