Messages in this thread | | | Date | Sat, 20 Mar 2004 23:00:16 -0800 | From | Chris Wedgwood <> | Subject | Re: can device drivers return non-ram via vm_ops->nopage? |
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On Sun, Mar 21, 2004 at 06:23:22AM +0000, Christoph Hellwig wrote:
> Not sure how you get to fetchop here, but that driver does map ram > pages so it should take pagefaults and not use remap_page_range().
It's been a while since I looked at this.... the fetchop driver maps AMO space which is excluded from the EFI memory map (and any SHub aliases) and thus shouldn't be touching anything normally considered RAM.
<pause>
Checking the source I see:
if (remap_page_range(vm_start, __pa(maddr), PAGE_SIZE, vma->vm_page_prot)) { fetchop_free_pages(vma->vm_private_data); vfree(vdata); fetchop_update_stats(-1, -pages); return -EAGAIN; }
as part of the drivers 'mmap fop'. The underlying page is actually from region-6 so I'm pretty sure it's safe. If you think it is doing something weird please let me know.
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