| Date | Thu, 28 Apr 2011 10:42:15 +0100 | From | Russell King - ARM Linux <> | Subject | Re: [RFC] ARM DMA mapping TODO, v1 |
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On Thu, Apr 28, 2011 at 07:31:06AM +1000, Benjamin Herrenschmidt wrote: > The question remains, if we ever want to do more complex demand-paged > operations, should we also expose a lower level set of functions to get > struct page out of a dma_alloc_coherent() allocation and to get the > pgprot for the user dma mapping ?
I don't think so - that places the requirement that dma_alloc_coherent() must be backed by memory with a set of struct page, which may not always be the case.
Think about dma_alloc_coherent() with dma_declare_coherent_memory() used with memory which is not part of system RAM.
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