Re: [PATCH 1/2] dma-mapping: fix page attributes for dma_mmap_*
From: Shawn Anastasio <hidden>
Date: 2019-08-06 19:47:21
Also in:
linux-arm-kernel, linux-iommu, linuxppc-dev, lkml
On 8/5/19 10:01 AM, Christoph Hellwig wrote:
quoted hunk ↗ jump to hunk
diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h index 3813211a9aad..9ae5cee543c4 100644 --- a/include/linux/dma-noncoherent.h +++ b/include/linux/dma-noncoherent.h@@ -42,13 +42,8 @@ void arch_dma_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs); long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr, dma_addr_t dma_addr); - -#ifdef CONFIG_ARCH_HAS_DMA_MMAP_PGPROT pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs); -#else -# define arch_dma_mmap_pgprot(dev, prot, attrs) pgprot_noncached(prot) -#endif
Nit, but maybe the prototype should still be ifdef'd here? It at least could prevent a reader from incorrectly thinking that the function is always present. Also, like Will mentioned earlier, the function name isn't entirely accurate anymore. I second the suggestion of using something like arch_dma_noncoherent_pgprot(). As for your idea of defining pgprot_dmacoherent for all architectures as #ifndef pgprot_dmacoherent #define pgprot_dmacoherent pgprot_noncached #endif I think that the name here is kind of misleading too, since this definition will only be used when there is no support for proper DMA coherency.