linux-kernel - [PATCH v9 21/60] PCI: Get new realloc size for bridge for last try

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Message-Id: <1449810416-2950-22-git-send-email-yinghai@kernel.org>
Date:	Thu, 10 Dec 2015 21:06:17 -0800
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>,
	Khalid Aziz <khalid.aziz@...cle.com>
Cc:	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	Yinghai Lu <yinghai@...nel.org>
Subject: [PATCH v9 21/60] 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 "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@....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 e4972f5..c2e3999 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1739,6 +1739,17 @@ 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
@@ -1823,8 +1834,13 @@ 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);
 
@@ -1898,8 +1914,11 @@ 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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