[PATCH v11 22/60] PCI: Get new realloc size for bridge for last try

[Yinghai Lu]

Current realloc path would not shrink bridge resource through
pbus_size_mem() checking with the old size.

That cause problem: when "required+optional" resource allocation fails,
the cached bridge resource size will prevent "required" resource to get
allocated smaller resource.

Clear the old resource size for last try or third and later try.

-v3: for last or third time and later.
     change reset_bridge_resource_size to static according to Fengguang.
-v4: don't clear size for bridge's normal resources.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=81431
Tested-by: TJ <linux@xxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
 drivers/pci/setup-bus.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 3dc4ac9..d3a39b7 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1738,6 +1738,17 @@ static enum enable_type pci_realloc_detect(struct pci_bus *bus,
 }
 #endif
 
+static void reset_bridge_resource_size(struct pci_dev *dev,
+				       struct resource *res)
+{
+	int idx = res - &dev->resource[0];
+
+	if (idx >= PCI_BRIDGE_RESOURCES && idx <= PCI_BRIDGE_RESOURCE_END) {
+		res->start = 0;
+		res->end = res->start - 1;
+	}
+}
+
 /*
  * first try will not touch pci bridge res
  * second and later try will clear small leaf bridge res
@@ -1822,8 +1833,13 @@ again:
 		res->start = fail_res->start;
 		res->end = fail_res->end;
 		res->flags = fail_res->flags;
-		if (fail_res->dev->subordinate)
+		if (fail_res->dev->subordinate) {
 			res->flags = 0;
+			/* last or third times and later */
+			if (tried_times + 1 == pci_try_num ||
+			    tried_times + 1 > 2)
+				reset_bridge_resource_size(fail_res->dev, res);
+		}
 	}
 	free_list(&fail_head);
 
@@ -1897,8 +1913,11 @@ again:
 		res->start = fail_res->start;
 		res->end = fail_res->end;
 		res->flags = fail_res->flags;
-		if (fail_res->dev->subordinate)
+		if (fail_res->dev->subordinate) {
 			res->flags = 0;
+			/* last time */
+			reset_bridge_resource_size(fail_res->dev, res);
+		}
 	}
 	free_list(&fail_head);
 
-- 
1.8.4.5