[PATCH v2] pci: pcie-xilinx: fix a missing-check bug for __get_free_pages

[Kangjie Lu]

In case __get_free_pages fail, the fix returns -ENOMEMto avoid
NULL pointer dereference.

Signed-off-by: Kangjie Lu <k...@umn.edu>
Reviewed-by: Steven Price <steven.pr...@arm.com>
---
v2: caller is redefined to accept the error code, as suggested by
Steven Price <steven.pr...@arm.com>
---
 drivers/pci/controller/pcie-xilinx.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-xilinx.c 
b/drivers/pci/controller/pcie-xilinx.c
index 9bd1a35cd5d8..abc214e94f7c 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -336,14 +336,19 @@ static const struct irq_domain_ops msi_domain_ops = {
  * xilinx_pcie_enable_msi - Enable MSI support
  * @port: PCIe port information
  */
-static void xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
+static int xilinx_pcie_enable_msi(struct xilinx_pcie_port *port)
 {
        phys_addr_t msg_addr;
 
        port->msi_pages = __get_free_pages(GFP_KERNEL, 0);
+       if (unlikely(!port->msi_pages))
+               return -ENOMEM;
+
        msg_addr = virt_to_phys((void *)port->msi_pages);
        pcie_write(port, 0x0, XILINX_PCIE_REG_MSIBASE1);
        pcie_write(port, msg_addr, XILINX_PCIE_REG_MSIBASE2);
+
+       return 0;
 }
 
 /* INTx Functions */
@@ -498,6 +503,7 @@ static int xilinx_pcie_init_irq_domain(struct 
xilinx_pcie_port *port)
        struct device *dev = port->dev;
        struct device_node *node = dev->of_node;
        struct device_node *pcie_intc_node;
+       int ret;
 
        /* Setup INTx */
        pcie_intc_node = of_get_next_child(node, NULL);
@@ -526,7 +532,9 @@ static int xilinx_pcie_init_irq_domain(struct 
xilinx_pcie_port *port)
                        return -ENODEV;
                }
 
-               xilinx_pcie_enable_msi(port);
+               ret = xilinx_pcie_enable_msi(port);
+               if (ret)
+                       return ret;
        }
 
        return 0;
-- 
2.17.1