Re: Does kmalloc always return address below 4GB?

Adam J. Richter
2002-03-05T11:52:44Z

>Just use pci_alloc_consistent, it never gives you
>anything larger than 32-bit addresses, please read the
>documentation :-)

I see the smiley, but let me point out that I have
read Documentation/DMA-mapping.txt and I was misled by this
sentence:

| If you acquired your memory via the page allocator
| (i.e. __get_free_page*()) or the generic memory allocators
| (i.e. kmalloc() or kmem_cache_alloc()) then you may DMA to/from
| that memory using the addresses returned from those routines.

It might be a good idea to rephrase it. If I knew what that
sentence I would propose a patch to the DMA-mapping.txt file, but I
honestly don't know what proposition that sentence is supposed
to convey. If there really is no guarantee that this sentence is
conveying, then I guess the sentence should be deleted.

Anyhow, thanks for your quick clarification. The driver
breaking on 64-bit architectures was exactly what I was worried about.

Adam J. Richter __ ______________ 4880 Stevens Creek Blvd, Suite 104
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