From mboxrd@z Thu Jan 1 00:00:00 1970 From: steve.capper@linaro.org (Steve Capper) Date: Tue, 18 Feb 2014 15:59:39 +0000 Subject: [PATCH V2] arm: mm: Remove hugetlb warning from Coherent DMA allocator In-Reply-To: <20140218154930.GG21483@n2100.arm.linux.org.uk> References: <1389866863-24460-1-git-send-email-steve.capper@linaro.org> <20140218154549.GA28193@linaro.org> <20140218154930.GG21483@n2100.arm.linux.org.uk> Message-ID: <20140218155938.GA28940@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > > > --- > > > 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