Is there any official statement on what the minimum alignment is for memory returned by dma_alloc_coherent? I know that since it uses a page allocator to do the actual allocation, that the memory is page aligned (at least on PowerPC). Is this something I can rely on?
Would anyone have a complaint if I did this: vaddr = dma_alloc_coherent(dev, ssize, &paddr, GFP_DMA | __GFP_ZERO); BUG_ON(paddr & (alignment - 1)); 'alignment' will always be 32 or less. The reason I ask is that I currently have code that ensures an alignment, but it does so by allocating extra memory, and that seems wasteful. On a side note, do I really need to pass GFP_DMA when calling dma_alloc_coherent? That seems redundant, but I don't see the code force it to be set. Should it be forced on? -- Timur Tabi Linux kernel developer at Freescale _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
