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Message-ID: <1344149396.24037.86.camel@pasglop>
Subject: Re: Is iommu_num_pages() broken ?
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: Joerg Roedel <joerg.roedel@amd.com>, Anton Blanchard <anton@au1.ibm.com>,
        FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
        linux-kernel@vger.kernel.org
Date: Sun, 05 Aug 2012 16:49:56 +1000
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On Sun, 2012-08-05 at 08:39 +0200, Andreas Schwab wrote:
> addr & (io_page_size - 1) computes the offset into the page pointed to
> by addr.  Looks right to me.
> 
> addr & ~(io_page_size - 1) would round addr down to the start of the
> page.

Ah that's right, for some reason I'm so used to seeing ~ before such
constructs that my brain must have imagined it :-)

Sorry for the noise. Next time I'll have coffee first then re-check ...

Cheers,
Ben.