Re: virt_to_bus and >1G of memory (was MAX_DMA_ADDRESS ...)

Linus Torvalds (torvalds@transmeta.com)
Fri, 13 Nov 1998 10:02:52 -0800 (PST)

On Fri, 13 Nov 1998, Jamie Lokier wrote:
>
> One thing I've seen in some drivers is that virt_to_bus doesn't work on
> a user-space address, _or_ an address in a module.

It will never work. It's not supposed to. Anybody trying to do that is
buggy.

The "virt_to_phys()" and "virt_to_bus()" things are _only_ supposed to
work on normal kernel mappings, the kind of mappings you get from
"get_free_pages()" etc. Assuming anything else is just stupid, because it
assumes a level of complexity that I never want to see.

Linus

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