On Wed, Nov 05, 2008 at 02:19:52PM +0100, Arnd Bergmann wrote:

On Tuesday 04 November 2008, Ira Snyder wrote:

quoted

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.

quoted

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