[PATCH 6/12] pci: don't shrink bridge resources

[Yinghai Lu <yinghai@kernel.org>]

when we are clearing leaf bridge resource and try to get big one, we could shrink the bridge if
there is no resource under it.

let check with old resource size and make sure we are trying to get big one.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 drivers/pci/setup-bus.c |   22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

Index: linux-2.6/drivers/pci/setup-bus.c
===================================================================
--- linux-2.6.orig/drivers/pci/setup-bus.c
+++ linux-2.6/drivers/pci/setup-bus.c
@@ -390,7 +390,7 @@ static void pbus_size_io(struct pci_bus
 {
 	struct pci_dev *dev;
 	struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
-	unsigned long size = 0, size1 = 0;
+	unsigned long size = 0, size1 = 0, old_size;
 
 	if (!b_res)
  		return;
@@ -415,17 +415,18 @@ static void pbus_size_io(struct pci_bus
 	}
 	if (size < min_size)
 		size = min_size;
+	old_size = resource_size(b_res);
+	if (old_size == 1)
+		old_size = 0;
 /* To be fixed in 2.5: we should have sort of HAVE_ISA
    flag in the struct pci_bus. */
 #if defined(CONFIG_ISA) || defined(CONFIG_EISA)
 	size = (size & 0xff) + ((size & ~0xffUL) << 2);
 #endif
 	size = ALIGN(size + size1, 4096);
+	if (size < old_size)
+		size = old_size;
 	if (!size) {
-		if (b_res->start || b_res->end)
-			dev_info(&bus->self->dev, "disabling bridge window "
-				 "%pR to [bus %02x-%02x] (unused)\n", b_res,
-				 bus->secondary, bus->subordinate);
 		b_res->flags = 0;
 		return;
 	}
@@ -441,7 +442,7 @@ static int pbus_size_mem(struct pci_bus
 			 unsigned long type, resource_size_t min_size)
 {
 	struct pci_dev *dev;
-	resource_size_t min_align, align, size;
+	resource_size_t min_align, align, size, old_size;
 	resource_size_t aligns[12];	/* Alignments from 1Mb to 2Gb */
 	int order, max_order;
 	struct resource *b_res = find_free_bus_resource(bus, type);
@@ -491,6 +492,11 @@ static int pbus_size_mem(struct pci_bus
 	}
 	if (size < min_size)
 		size = min_size;
+	old_size = resource_size(b_res);
+	if (old_size == 1)
+		old_size = 0;
+	if (size < old_size)
+		size = old_size;
 
 	align = 0;
 	min_align = 0;
@@ -507,10 +513,6 @@ static int pbus_size_mem(struct pci_bus
 	}
 	size = ALIGN(size, min_align);
 	if (!size) {
-		if (b_res->start || b_res->end)
-			dev_info(&bus->self->dev, "disabling bridge window "
-				 "%pR to [bus %02x-%02x] (unused)\n", b_res,
-				 bus->secondary, bus->subordinate);
 		b_res->flags = 0;
 		return 1;
 	}