On Thu, 2012-07-19 at 09:42 -0500, Seth Jennings wrote:

This patch adds the driver for interacting with the 842
compression accelerator on IBM Power7+ systems.

...

+struct nx842_slentry {
+	unsigned long ptr; /* Absolute address (use virt_to_abs()) */
/+	unsigned long len;
+};

These days virt_to_abs() is just __pa() - ie. convert to a real address.

So you should just use __pa().

And you also need to be certain that you only call it on addresses where
that makes sense, ie. not vmalloc etc.

cheers