linux-kernel - [PATCH v3 44/51] PCI: Get new realloc size for bridge for last try

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Date:	Mon, 27 Jul 2015 16:30:02 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Bjorn Helgaas <bhelgaas@...gle.com>,
	David Miller <davem@...emloft.net>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Wei Yang <weiyang@...ux.vnet.ibm.com>, TJ <linux@....tj>,
	Yijing Wang <wangyijing@...wei.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	Yinghai Lu <yinghai@...nel.org>
Subject: [PATCH v3 44/51] PCI: Get new realloc size for bridge for last try

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

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

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

-v3: change reset_bridge_resource_size to static according to Fengguang.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=81431
Tested-by: TJ <linux@....tj>
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
 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 541cea5..83e3201 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -2256,6 +2256,17 @@ 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
@@ -2338,8 +2349,13 @@ again:
 		struct resource *res = fail_res->res;
 
 		restore_resource(fail_res, res);
-		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);
 
@@ -2411,8 +2427,11 @@ again:
 		struct resource *res = fail_res->res;
 
 		restore_resource(fail_res, res);
-		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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