Re: Will __pa(vmalloc()) ever work?

[Timur Tabi]

Gerd Knorr wrote:

> You should use vmalloc_to_page() (this does the page-table walking
> with correct locking), then the usual dma mapping interface
> (pci_map_page() or pci_map_sg()) to get bus address(es) you can pass
> to your device for DMA.

My problem is that I don't know where the memory came from.  It could have been allocated 
via kmalloc, or vmalloc, or anywhere else.  Can I call vmalloc_to_page() on memory 
allocated via kmalloc()?  If the answer is no, then how can I tell whether the memory was 
allocated via vmalloc() or some other method?  I need a reliable virtual-to-physical (or 
virtual-to-bus, which is the same thing on x86 architectures) method for any memory address.

--
Timur Tabi
Staff Software Engineer
timur.tabi@xxxxxxxxxxx

One thing a Southern boy will never say is,
"I don't think duct tape will fix it."
     -- Ed Smylie, NASA engineer for Apollo 13
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/