[PATCH V2] arm: mm: Remove hugetlb warning from Coherent DMA allocator

Steve Capper steve.capper at linaro.org
Tue Feb 18 10:59:39 EST 2014


On Tue, Feb 18, 2014 at 03:49:30PM +0000, Russell King - ARM Linux wrote:
> On Tue, Feb 18, 2014 at 03:45:51PM +0000, Steve Capper wrote:
> > On Thu, Jan 16, 2014 at 10:07:43AM +0000, Steve Capper wrote:
> > > The Coherant DMA allocator allocates pages of high order then splits
> > > them up into smaller pages.
> > > 
> > > This splitting logic would run into problems if the allocator was
> > > given compound pages. Thus the Coherant DMA allocator was originally
> > > incompatible with compound pages existing and, by extension, huge
> > > pages. A compile #error was put in place whenever huge pages were
> > > enabled.
> > > 
> > > Compatibility with compound pages has since been introduced by the
> > > following commit (which merely excludes GFP_COMP pages from being
> > > requested by the coherant DMA allocator):
> > >   ea2e705 ARM: 7172/1: dma: Drop GFP_COMP for DMA memory allocations
> > > 
> > > When huge page support was introduced to ARM, the compile #error in
> > > dma-mapping.c was replaced by a #warning when it should have been
> > > removed instead.
> > > 
> > > This patch removes the compile #warning in dma-mapping.c when huge
> > > pages are enabled.
> > > 
> > > Signed-off-by: Steve Capper <steve.capper at linaro.org>
> > > ---
> > > Changed in V2: commit message completely re-written to give a better
> > > justification.
> > > ---
> > >  arch/arm/mm/dma-mapping.c | 3 ---
> > >  1 file changed, 3 deletions(-)
> > 
> > Would anyone object to this going into Russell's patch system?
> 
> It's been a month, no one's objected, so please put it in the patch
> system anyway, thanks.
> 

Cheers, that's in as 7979/1.

-- 
Steve



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