Messages in this thread | | | Subject | Re: [PATCH 1/2] dma-mapping: fix page attributes for dma_mmap_* | From | Shawn Anastasio <> | Date | Wed, 7 Aug 2019 13:45:51 +0200 |
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On 8/7/19 8:04 AM, Christoph Hellwig wrote: > Actually it is typical modern Linux style to just provide a prototype > and then use "if (IS_ENABLED(CONFIG_FOO))" to guard the call(s) to it.
I see.
>> 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 mentioned I plan to remove arch_dma_mmap_pgprot for 5.4, so I'd > rather avoid churn for the short period of time.
Yeah, fair enough.
>> 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. > > Do you have a suggestion for a better name? I'm pretty bad at naming, > so just reusing the arm name seemed like a good way to avoid having > to make naming decisions myself.
Good question. Perhaps something like `pgprot_dmacoherent_fallback` would better convey that this is only used for devices that don't support DMA coherency? Or maybe `pgprot_dma_noncoherent`?
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