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Commit 8108de97 authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by James Bottomley
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[SCSI] gdth: Remove buggy ROM handling 



The ROM address handling in gdth_init_pci() is useless and possibly
dangerous.  This patch removes it.

"pci_resource_start(pdev, 8)" is not well-defined.  PCI resources 0-5 are
standard PCI BARs and 6 is the expansion ROM.  Resource 8 is either an
SR-IOV BAR (if CONFIG_PCI_IOV=y, resources 7-12 are SR-IOV BARs) or a
bridge window (resources 7-10).

The GDT device is neither an SR-IOV device nor a bridge, so in either case
resource 8 should be zero since struct pci_dev is allocated with kzalloc().

It is illegal for a driver to write an arbitrary address to the ROM BAR
because it has no way of knowing whether the ROM will conflict with another
device.

I think the only effect of the code being removed was to:

  1) Enable the ROM at 0xFEFF0000 (possibly causing a conflict with
     another device)
  2) Delay one millisecond
  3) Write zero to the ROM BAR, disabling it

I doubt the delay is needed, but I left it since it seems innocuous.

Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent f94d4fe0

drivers/scsi/gdth.c

+2 −8
Original line number Diff line number Diff line
@@ -1107,13 +1107,7 @@ static int gdth_init_pci(struct pci_dev *pdev, gdth_pci_str *pcistr, 
	pci_read_config_word(pdev, PCI_COMMAND, &command);

        command |= 6;

	pci_write_config_word(pdev, PCI_COMMAND, command);

	if (pci_resource_start(pdev, 8) == 1UL)

	    pci_resource_start(pdev, 8) = 0UL;

        i = 0xFEFF0001UL;

	pci_write_config_dword(pdev, PCI_ROM_ADDRESS, i);

	gdth_delay(1);

	pci_write_config_dword(pdev, PCI_ROM_ADDRESS,

			       pci_resource_start(pdev, 8));



        dp6m_ptr = ha->brd;