Re: alpha iommu fixes

[Andrea Arcangeli]

On Mon, May 21, 2001 at 02:54:16AM +1000, Andrew Morton wrote:
> No.  Most of the pci_map_single() implementations just
> use virt_to_bus()/virt_to_phys(). [..]

then you are saying that on the platforms without an iommu the pci_map_*
cannot fail, of course, furthmore even a missing pci_unmap cannot
trigger an iommu address space leak on those platforms. That has nothing
to do with the fact pci_map_single can fail or not, the device drivers
are not architectural specific.

> [..]  Even sparc64's fancy
> iommu-based pci_map_single() always succeeds.

Whatever sparc64 does to hide the driver bugs you can break it if you
pci_map 4G+1 bytes of phyical memory.  Otherwise it means it's sleeping
or looping inside the pci_map functions which would break things in
another manner.

Andrea