[PATCH AUTOSEL 4.9 04/13] PCI: tegra: Fix OF node reference leak

[Sasha Levin <sashal@xxxxxxxxxx>]

From: Nishka Dasgupta <nishkadg.linux@xxxxxxxxx>

[ Upstream commit 9e38e690ace3e7a22a81fc02652fc101efb340cf ]

Each iteration of for_each_child_of_node() executes of_node_put() on the
previous node, but in some return paths in the middle of the loop
of_node_put() is missing thus causing a reference leak.

Hence stash these mid-loop return values in a variable 'err' and add a
new label err_node_put which executes of_node_put() on the previous node
and returns 'err' on failure.

Change mid-loop return statements to point to jump to this label to
fix the reference leak.

Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@xxxxxxxxx>
[lorenzo.pieralisi@xxxxxxx: rewrote commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/pci/host/pci-tegra.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 8dfccf7332411..8e101b19c4d6f 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -1898,14 +1898,15 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
 		err = of_pci_get_devfn(port);
 		if (err < 0) {
 			dev_err(dev, "failed to parse address: %d\n", err);
-			return err;
+			goto err_node_put;
 		}
 
 		index = PCI_SLOT(err);
 
 		if (index < 1 || index > soc->num_ports) {
 			dev_err(dev, "invalid port number: %d\n", index);
-			return -EINVAL;
+			err = -EINVAL;
+			goto err_node_put;
 		}
 
 		index--;
@@ -1914,12 +1915,13 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
 		if (err < 0) {
 			dev_err(dev, "failed to parse # of lanes: %d\n",
 				err);
-			return err;
+			goto err_node_put;
 		}
 
 		if (value > 16) {
 			dev_err(dev, "invalid # of lanes: %u\n", value);
-			return -EINVAL;
+			err = -EINVAL;
+			goto err_node_put;
 		}
 
 		lanes |= value << (index << 3);
@@ -1933,13 +1935,15 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
 		lane += value;
 
 		rp = devm_kzalloc(dev, sizeof(*rp), GFP_KERNEL);
-		if (!rp)
-			return -ENOMEM;
+		if (!rp) {
+			err = -ENOMEM;
+			goto err_node_put;
+		}
 
 		err = of_address_to_resource(port, 0, &rp->regs);
 		if (err < 0) {
 			dev_err(dev, "failed to parse address: %d\n", err);
-			return err;
+			goto err_node_put;
 		}
 
 		INIT_LIST_HEAD(&rp->list);
@@ -1966,6 +1970,10 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
 		return err;
 
 	return 0;
+
+err_node_put:
+	of_node_put(port);
+	return err;
 }
 
 /*
-- 
2.20.1