[parisc-linux] tulip DMA mapping

[Grant Grundler <grundler@cup.hp.com>]

Hi all,
I see a "bug" in tulip's usage of mapping services.
It's not the bug I was looking for unfortunately.

In line 217 of drivers/net/tulip/interrupt.c:

	if (tp->tx_buffers[entry].mapping)
		pci_unmap_single(tp->pdev,
				tp->tx_buffers[entry].mapping,
				sizeof(tp->setup_frame),
				PCI_DMA_TODEVICE);

0 is a valid pci_map_single() return value when the system has an IO MMU.

The system will panic before pci_map_single() will fail.
The driver needs to remember some other way if a buffer was mapped or not.
Or the Documentation/DMA-mapping.txt should be changed - ie add this
to the interface definition and I can reserve the 1st mapping
entry so no-one uses it.

Should I be mailing Jeff Garzik <jgarzik@mandrakesoft.com> directly?
Or can someone who knows Jeff point this out to him?

thanks,
grant