On Wed, 2017-03-15 at 17:54 +0000, Mark Rutland wrote:

It's not so much "broken" as "not currently supported".

Yeah, I thought that when I inherited the commit, but didn't get as far
as rephrasing it. Will do so.

[...]

quoted

+#define HAVE_PCI_MMAP
+extern int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
+			???????enum pci_mmap_state mmap_state, int write_combine);
+

Per the prior attempt at this [1], we only want to expose the sysfs
interface, and not the legacy procfs interface, and need the two
decoupled [2].

I do not like that idea. The procfs horridness is legacy, sure, but
it's not actually an arch-specific interface. You get to mess with
'legacy' syscalls all you like on a new architecture, but there could
exist arch-agnostic code which uses the procfs interface, surely?

quoted

+	if (write_combine)
+		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+	else
+		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

... as per Will's comment in [3], the latter of these should use
pgprot_device.

Will fix that; thanks.
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