Allocate from the end of a region, not the beginning.
For example, if we need to allocate 0x800 bytes for a device on bus
0000:00 given these resources:
[mem 0xbff00000-0xdfffffff] PCI Bus 0000:00
[mem 0xc0000000-0xdfffffff] PCI Bus 0000:02
the available space at [mem 0xbff00000-0xbfffffff] is passed to the
alignment callback (pcibios_align_resource()). Prior to this patch, we
would put the new 0x800 byte resource at the beginning of that available
space, i.e., at [mem 0xbff00000-0xbff007ff].
With this patch, we put it at the end, at [mem 0xbffff800-0xbfffffff].
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=16228#c41
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@xxxxxx>
---
arch/x86/pci/i386.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 5525309..1ff3e9f 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -65,7 +65,10 @@ pcibios_align_resource(void *data, const struct resource *res,
resource_size_t size, resource_size_t align)
{
struct pci_dev *dev = data;
- resource_size_t start = res->start;
+ resource_size_t start = ALIGN(res->end - size + 1, align);
+
+ if (start < res->start)
+ start = res->start;
if (res->flags & IORESOURCE_IO) {
if (skip_isa_ioresource_align(dev))
--
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