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Date: Wed, 5 Nov 2008 11:18:41 -0800
From: Ira Snyder <iws@ovro.caltech.edu>
To: Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH RFC v2] net: add PCINet driver
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Cc: linuxppc-dev@ozlabs.org, Stephen Hemminger <shemminger@vyatta.com>,
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On Wed, Nov 05, 2008 at 02:19:52PM +0100, Arnd Bergmann wrote:
> On Tuesday 04 November 2008, Ira Snyder wrote:
> 
> > So, since interrupts are disabled while my interrupt handler is running,
> > I think I should be able to use spin_lock() and spin_unlock(), correct?
> 
> yes.
> 
> > But sparse gives me the following warning:
> > wqt.c:185:9: warning: context imbalance in 'wqt_interrupt': wrong count at exit
> > wqt.c:185:9:    context 'lock': wanted 0, got 1
> > 
> > If I'm using spin_lock_irqsave() and spin_lock_irqrestore() I do not get
> > the same warnings. Therefore I must have some misunderstanding :)
> 
> 
> I've seen something like that before, I think it was a bug either in
> sparse or in the powerpc platform code. Try updating both the kernel
> and sparse and see if it still happens.
> 

Ok, I had the latest sparse, but I've been developing the host driver
against Ubuntu 8.04's kernel, which is based on 2.6.24. Using Linus' git
tree resolved the errors from sparse.

I ended up finding that the dma_mapping_error() API has changed, and so
I updated the driver for that. It should build against 2.6.28-rc now.
I'll post it in a little while.

Ira