[PATCH v6 10/53] 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.

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 9961ab2..8477cf5 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1648,6 +1648,17 @@ 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
@@ -1732,8 +1743,13 @@ 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);
 
@@ -1807,8 +1823,11 @@ 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

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