On Mon, Mar 10, 2025 at 02:56:37PM +0000, Robin Murphy wrote: > On 2025-03-10 12:06 pm, Maxime Ripard wrote: > > Consumers of the direct DMA API will have to know which region their > > device allocate from in order for them to charge the memory allocation > > in the right one. > > This doesn't seem to make much sense - dma-direct is not an allocator > itself, it just provides the high-level dma_alloc_attrs/dma_alloc_pages/etc. > interfaces wherein the underlying allocations _could_ come from CMA, but > also a per-device coherent/restricted pool, or a global coherent/atomic > pool, or the regular page allocator, or in one weird corner case the SWIOTLB > buffer, or... I guess it wasn't super clear, but what I meant is that it's an allocator to the consumer: it gets called, and returns a buffer. How it does so is transparent to the device, and on the other side of the abstraction. I do agree that the logic is complicated to follow, and that's what I was getting at in the cover letter. Maxime
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