[3.16.y-ckt stable] Patch "PCI: Add pci_bus_clip_resource() to clip to fit upstream window" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    PCI: Add pci_bus_clip_resource() to clip to fit upstream window

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ca09326f6ec8f9c88677bf3c90945a7fd080117f Mon Sep 17 00:00:00 2001
From: Yinghai Lu <yinghai at kernel.org>
Date: Thu, 15 Jan 2015 16:21:49 -0600
Subject: PCI: Add pci_bus_clip_resource() to clip to fit upstream window

commit 0f7e7aee2f37119a32e6e8b63250922442528961 upstream.

Add pci_bus_clip_resource().  If a PCI-PCI bridge window overlaps an
upstream bridge window but is not completely contained by it, this clips
the downstream window so it fits inside the upstream one.

No functional change (this adds the function but no callers).

[bhelgaas: changelog, split into separate patch]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=85491
Reported-by: Marek Kordik <kordikmarek at gmail.com>
Fixes: 5b28541552ef ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources")
Signed-off-by: Yinghai Lu <yinghai at kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/pci/bus.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 drivers/pci/pci.h |  1 +
 2 files changed, 44 insertions(+)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 73aef51a28f0..8fb16188cd82 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -228,6 +228,49 @@ int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
 }
 EXPORT_SYMBOL(pci_bus_alloc_resource);

+/*
+ * The @idx resource of @dev should be a PCI-PCI bridge window.  If this
+ * resource fits inside a window of an upstream bridge, do nothing.  If it
+ * overlaps an upstream window but extends outside it, clip the resource so
+ * it fits completely inside.
+ */
+bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
+{
+	struct pci_bus *bus = dev->bus;
+	struct resource *res = &dev->resource[idx];
+	struct resource orig_res = *res;
+	struct resource *r;
+	int i;
+
+	pci_bus_for_each_resource(bus, r, i) {
+		resource_size_t start, end;
+
+		if (!r)
+			continue;
+
+		if (resource_type(res) != resource_type(r))
+			continue;
+
+		start = max(r->start, res->start);
+		end = min(r->end, res->end);
+
+		if (start > end)
+			continue;	/* no overlap */
+
+		if (res->start == start && res->end == end)
+			return false;	/* no change */
+
+		res->start = start;
+		res->end = end;
+		dev_printk(KERN_DEBUG, &dev->dev, "%pR clipped to %pR\n",
+				 &orig_res, res);
+
+		return true;
+	}
+
+	return false;
+}
+
 void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }

 /**
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 0601890db22d..357ea8cfab08 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -206,6 +206,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus,
 void __pci_bus_assign_resources(const struct pci_bus *bus,
 				struct list_head *realloc_head,
 				struct list_head *fail_head);
+bool pci_bus_clip_resource(struct pci_dev *dev, int idx);

 /**
  * pci_ari_enabled - query ARI forwarding status
--
2.1.4