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Date: Wed, 14 Oct 2015 08:42:51 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
 Matthew Wilcox <willy@linux.intel.com>,
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 linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 1/5 v2] dma-mapping: add generic dma_get_page_shift API
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Hi Nishanth,

sorry for the late reply.

> > On Power, since it's technically variable, we'd need a function. So are
> > you suggesting define'ing it to a function just on Power and leaving it
> > a constant elsewhere?
> > 
> > I noticed that sparc has a IOMMU_PAGE_SHIFT already, fwiw.
> 
> Sorry, I should have been more specific -- I'm ready to spin out a v3,
> with a sparc-specific function.
> 
> Are you ok with leaving it a function for now (the only caller is in
> NVMe obviously).


I guess we do indeed need a function then.  I'll take a look at your
patch, but as long you found a way to avoid adding too much boilerplate
code it should be fine.