Messages in this thread | | | Date | Thu, 2 Dec 1999 13:00:54 +0100 (CET) | From | Ingo Molnar <> | Subject | Re: DMA and Cache coherency on machines without hardware enforced cache coherency. |
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On Thu, 2 Dec 1999, Roman Zippel wrote:
> > ioremap_nocache(). You can also use ioremap_nocache() on allocated pages > > (it's a page granularity thing) via doing something like: > > > > page = __get_free_pages(whatever, order); > > ptr = ioremap_nocache(virt_to_phys(page), 1 << > > (order+PAGE_SHIFT)); > > But the problem is that this mapping is never released if you call > iounmap() and if you remove that check there, vfree tries to free not only > the mapping but also any non reserved page. I think we really need a real > memremap() interface...
sigh. if you read the rest of my mail which you quote, i gave the exact changes which are needed to get around this, and i suggested a new memmap_nocache() interface.
-- mingo
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