Messages in this thread | | | Date | Wed, 2 May 2018 14:41:51 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH] swiotlb: Fix inversed DMA_ATTR_NO_WARN test |
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On Wed, May 02, 2018 at 02:18:56PM +0200, Daniel Vetter wrote: > Other dma-api backends like cma just shut up when __GFP_NOWARN is > passed. And afaiui Christoph Hellwig has plans to nuke the DMA_ATTR > stuff (or at least clean it up) - should we just remove > DMA_ATTR_NO_WARN and instead only look at __GFP_NOWARN?
No. __GFP_NOWARN (and gfp_t flags in general) are the wrong interface for dma allocations and just cause problems. I actually plan to get rid of the gfp_t argument in dma_alloc_attrs sooner, and only allow either GFP_KERNEL or GFP_DMA passed in dma_alloc_coherent.
> Or maybe we should at least enforce that both or none are set, for > consistency for now?
The interface should be DMA_ATTR_NO_WARN. __GFP_NOWARN in this context was never documented, and just slipped in.
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