PCI: keystone: Fix interrupt-controller-node lookup

commit eac56aa3bc8af3d9b9850345d0f2da9d83529134 upstream.

Fix child-node lookup during initialisation which was using the wrong
OF-helper and ended up searching the whole device tree depth-first
starting at the parent rather than just matching on its children.

To make things worse, the parent pci node could end up being prematurely
freed as of_find_node_by_name() drops a reference to its first argument.
Any matching child interrupt-controller node was also leaked.

Fixes: 0c4ffcfe1fbc ("PCI: keystone: Add TI Keystone PCIe driver")
Cc: stable <stable@vger.kernel.org>     # 3.18
Acked-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
[lorenzo.pieralisi@arm.com: updated commit subject]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[johan: backport to 4.4]
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
index 0aa81bd..fb682e8 100644 (file)
--- a/drivers/pci/host/pci-keystone.c
+++ b/drivers/pci/host/pci-keystone.c
@@ -179,14 +179,16 @@ static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
        }
 
        /* interrupt controller is in a child node */
-       *np_temp = of_find_node_by_name(np_pcie, controller);
+       *np_temp = of_get_child_by_name(np_pcie, controller);
        if (!(*np_temp)) {
                dev_err(dev, "Node for %s is absent\n", controller);
                goto out;
        }
        temp = of_irq_count(*np_temp);
-       if (!temp)
+       if (!temp) {
+               of_node_put(*np_temp);
                goto out;
+       }
        if (temp > max_host_irqs)
                dev_warn(dev, "Too many %s interrupts defined %u\n",
                        (legacy ? "legacy" : "MSI"), temp);
@@ -200,6 +202,9 @@ static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
                if (!host_irqs[temp])
                        break;
        }
+
+       of_node_put(*np_temp);
+
        if (temp) {
                *num_irqs = temp;
                ret = 0;