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x86/PCI: Coalesce multiple overlapping host bridge windows

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Previously we coalesced windows by expanding the first overlapping one and
making the second invalid.  But we never look at the expanded first window
again, so we fail to notice other windows that overlap it.  For example, we
coalesced these:

  [io  0x0000-0x03af] // #0
  [io  0x03e0-0x0cf7] // #1
  [io  0x0000-0xdfff] // #2

into these, which still overlap:

  [io  0x0000-0xdfff] // #0
  [io  0x03e0-0x0cf7] // #1

The fix is to expand the *second* overlapping resource and ignore the
first, so we get this instead with no overlaps:

  [io  0x0000-0xdfff] // #2

[bhelgaas: changelog]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=62511
Signed-off-by: Alexey Neyman <stilor@att.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Alexey Neyman 2013-10-09 16:16:38 -06:00 committed by Bjorn Helgaas
parent 6b49ee49af
commit 3ad674d6c6
1 changed files with 4 additions and 4 deletions
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8
arch/x86/pci/acpi.c
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@ -354,12 +354,12 @@ static void coalesce_windows(struct pci_root_info *info, unsigned long type)
* the kernel resource tree doesn't allow overlaps.
*/
if (resource_overlaps(res1, res2)) {
res1->start = min(res1->start, res2->start);
res1->end = max(res1->end, res2->end);
res2->start = min(res1->start, res2->start);
res2->end = max(res1->end, res2->end);
dev_info(&info->bridge->dev,
"host bridge window expanded to %pR; %pR ignored\n",
res1, res2);
res2->flags = 0;
res2, res1);
res1->flags = 0;
}
}
}