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

[Kangjie Lu]

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

Signed-off-by: Kangjie Lu <k...@umn.edu>
---
 drivers/pci/controller/pcie-xilinx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/controller/pcie-xilinx.c 
b/drivers/pci/controller/pcie-xilinx.c
index 9bd1a35cd5d8..b7083e995c45 100644
--- a/drivers/pci/controller/pcie-xilinx.c
+++ b/drivers/pci/controller/pcie-xilinx.c
@@ -341,6 +341,9 @@ static void 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;
+
        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);
-- 
2.17.1