Re: Will __pa(vmalloc()) ever work?
From: Timur Tabi
Date: Tue May 31 2005 - 10:55:09 EST
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.
Staff Software Engineer
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
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