diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 1eecfa301f7fb2efbfd025f70d39b7d159a42dde..8e075ea2743ef41b4ed08065f502527cbe804c82 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -686,7 +686,7 @@ static ssize_t driver_override_store(struct device *dev,
 				     const char *buf, size_t count)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
-	char *driver_override, *old = pdev->driver_override, *cp;
+	char *driver_override, *old, *cp;
 
 	/* We need to keep extra room for a newline */
 	if (count >= (PAGE_SIZE - 1))
@@ -700,12 +700,15 @@ static ssize_t driver_override_store(struct device *dev,
 	if (cp)
 		*cp = '\0';
 
+	device_lock(dev);
+	old = pdev->driver_override;
 	if (strlen(driver_override)) {
 		pdev->driver_override = driver_override;
 	} else {
 		kfree(driver_override);
 		pdev->driver_override = NULL;
 	}
+	device_unlock(dev);
 
 	kfree(old);
 
@@ -716,8 +719,12 @@ static ssize_t driver_override_show(struct device *dev,
 				    struct device_attribute *attr, char *buf)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
+	ssize_t len;
 
-	return snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override);
+	device_lock(dev);
+	len = snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override);
+	device_unlock(dev);
+	return len;
 }
 static DEVICE_ATTR_RW(driver_override);
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index f68c58a93dd045b9b58de9882088621253ec7758..f4f8ee5a7362e982c0084d619c8ed1996a38f770 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1685,6 +1685,8 @@ static inline int pci_get_new_domain_nr(void) { return -ENOSYS; }
 
 #define dev_is_pci(d) (false)
 #define dev_is_pf(d) (false)
+static inline bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags)
+{ return false; }
 #endif /* CONFIG_PCI */
 
 /* Include architecture-dependent settings and functions */