Subject: Re: [PATCH 3/4] powerpc/crypto: add 842 hardware compression driver

From: Michael Ellerman <[email-masked]>
Date: Fri, 20 Jul 2012 15:33:30 +1000

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