Messages in this thread | | | From | Marek Szyprowski <> | Subject | RE: [Linaro-mm-sig] [PATCHv2 1/6] common: DMA-mapping: add DMA_ATTR_NO_KERNEL_MAPPING attribute | Date | Thu, 14 Jun 2012 11:01:11 +0200 |
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Hello,
On Wednesday, June 13, 2012 8:52 PM Daniel Vetter wrote:
> On Wed, Jun 13, 2012 at 01:50:13PM +0200, Marek Szyprowski wrote: > > This patch adds DMA_ATTR_NO_KERNEL_MAPPING attribute which lets the > > platform to avoid creating a kernel virtual mapping for the allocated > > buffer. On some architectures creating such mapping is non-trivial task > > and consumes very limited resources (like kernel virtual address space > > or dma consistent address space). Buffers allocated with this attribute > > can be only passed to user space by calling dma_mmap_attrs(). > > > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > > Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com> > > Looks like a nice little extension to support dma-buf for the common case, > so: > > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> > > One question is whether we should go right ahead and add kmap support for > this, too (with a default implementation that simply returns a pointer to > the coherent&contigous dma mem), but I guess that can wait until a > use-case pops up.
I will wait with this until there will be real use cases. Let's get the patch into mainline first.
Best regards -- Marek Szyprowski Samsung Poland R&D Center
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