linux-kernel - [PATCH 4.2.y-ckt 087/268] PCI: Fix minimum allocation address overwrite

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Date:	Wed, 27 Jan 2016 12:32:28 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Christoph Biedl <linux-kernel.bfrz@...chmal.in-ulm.de>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 4.2.y-ckt 087/268] PCI: Fix minimum allocation address overwrite

4.2.8-ckt3 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Christoph Biedl <linux-kernel.bfrz@...chmal.in-ulm.de>

commit 3460baa620685c20f5ee19afb6d99d26150c382c upstream.

Commit 36e097a8a297 ("PCI: Split out bridge window override of minimum
allocation address") claimed to do no functional changes but unfortunately
did: The "min" variable is altered.  At least the AVM A1 PCMCIA adapter was
no longer detected, breaking ISDN operation.

Use a local copy of "min" to restore the previous behaviour.

[bhelgaas: avoid gcc "?:" extension for portability and readability]
Fixes: 36e097a8a297 ("PCI: Split out bridge window override of minimum allocation address")
Signed-off-by: Christoph Biedl <linux-kernel.bfrz@...chmal.in-ulm.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 drivers/pci/bus.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index d3346d2..89b3bef 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -140,6 +140,8 @@ static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
 	type_mask |= IORESOURCE_TYPE_BITS;
 
 	pci_bus_for_each_resource(bus, r, i) {
+		resource_size_t min_used = min;
+
 		if (!r)
 			continue;
 
@@ -163,12 +165,12 @@ static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
 		 * overrides "min".
 		 */
 		if (avail.start)
-			min = avail.start;
+			min_used = avail.start;
 
 		max = avail.end;
 
 		/* Ok, try it out.. */
-		ret = allocate_resource(r, res, size, min, max,
+		ret = allocate_resource(r, res, size, min_used, max,
 					align, alignf, alignf_data);
 		if (ret == 0)
 			return 0;
-- 
1.9.1