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`?
