[PATCH 5.7 124/244] PCI/PM: Call .bridge_d3() hook only if non-NULL

[Greg Kroah-Hartman]

From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

commit c3aaf086701d05a82c8156ee8620af41e5a7d6fe upstream.

26ad34d510a8 ("PCI / ACPI: Whitelist D3 for more PCIe hotplug ports") added
the struct pci_platform_pm_ops.bridge_d3() function pointer and
platform_pci_bridge_d3() to use it.

The .bridge_d3() op is implemented by acpi_pci_platform_pm, but not by
mid_pci_platform_pm.  We don't expect platform_pci_bridge_d3() to be called
on Intel MID platforms, but nothing in the code itself would prevent that.

Check the .bridge_d3() pointer for NULL before calling it.

Fixes: 26ad34d510a8 ("PCI / ACPI: Whitelist D3 for more PCIe hotplug ports")
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/pci/pci.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -868,7 +868,9 @@ static inline bool platform_pci_need_res
 
 static inline bool platform_pci_bridge_d3(struct pci_dev *dev)
 {
-	return pci_platform_pm ? pci_platform_pm->bridge_d3(dev) : false;
+	if (pci_platform_pm && pci_platform_pm->bridge_d3)
+		return pci_platform_pm->bridge_d3(dev);
+	return false;
 }
 
 /**