linux-kernel - [RFC v5 2/7] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources

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Date:	Tue,  5 Apr 2016 21:43:30 +0800
From:	Yongji Xie <xyjxie@...ux.vnet.ibm.com>
To:	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	linux-doc@...r.kernel.org
Cc:	bhelgaas@...gle.com, corbet@....net, aik@...abs.ru,
	alex.williamson@...hat.com, benh@...nel.crashing.org,
	paulus@...ba.org, mpe@...erman.id.au, warrier@...ux.vnet.ibm.com,
	zhong@...ux.vnet.ibm.com, nikunj@...ux.vnet.ibm.com,
	gwshan@...ux.vnet.ibm.com, Yongji Xie <xyjxie@...ux.vnet.ibm.com>
Subject: [RFC v5 2/7] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources

Now we use the IORESOURCE_STARTALIGN to identify
bridge resources in __assign_resources_sorted().
That's quite fragile. We can't make sure that
the PCI devices' resources will not use
IORESOURCE_STARTALIGN any more.

In this patch, we try to use a more robust way
to identify bridge resources.

Signed-off-by: Yongji Xie <xyjxie@...ux.vnet.ibm.com>
---
 drivers/pci/setup-bus.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 7796d0a..bffcf1e 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -391,6 +391,7 @@ static void __assign_resources_sorted(struct list_head *head,
 	struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
 	unsigned long fail_type;
 	resource_size_t add_align, align;
+	int index;
 
 	/* Check if optional add_size is there */
 	if (!realloc_head || list_empty(realloc_head))
@@ -411,11 +412,14 @@ static void __assign_resources_sorted(struct list_head *head,
 
 		/*
 		 * There are two kinds of additional resources in the list:
-		 * 1. bridge resource  -- IORESOURCE_STARTALIGN
-		 * 2. SR-IOV resource   -- IORESOURCE_SIZEALIGN
+		 * 1. bridge resource
+		 * 2. SR-IOV resource
 		 * Here just fix the additional alignment for bridge
 		 */
-		if (!(dev_res->res->flags & IORESOURCE_STARTALIGN))
+		index = dev_res->res - dev_res->dev->resource;
+		if (pci_is_bridge(dev_res->dev) &&
+			index >= PCI_BRIDGE_RESOURCES &&
+			index <= PCI_BRIDGE_RESOURCE_END)
 			continue;
 
 		add_align = get_res_add_align(realloc_head, dev_res->res);
-- 
1.7.9.5