diff --git a/init/devices.cpp b/init/devices.cpp
index 4de1e20..2cdecec 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -307,7 +307,8 @@
     return false;
 }
 
-bool DeviceHandler::FindPlatformDevice(std::string path, std::string* platform_device_path) const {
+bool DeviceHandler::FindPlatformDevice(const std::string& path,
+                                       std::string* platform_device_path) const {
     const std::set<std::string> subsystem_paths = {
             sysfs_mount_point_ + "/bus/platform",
             sysfs_mount_point_ + "/bus/amba",
@@ -316,7 +317,7 @@
     return FindSubsystemDevice(path, platform_device_path, subsystem_paths);
 }
 
-bool DeviceHandler::FindMmcDevice(std::string path, std::string* mmc_device_path) const {
+bool DeviceHandler::FindMmcDevice(const std::string& path, std::string* mmc_device_path) const {
     const std::set<std::string> subsystem_paths = {
             sysfs_mount_point_ + "/bus/mmc",
     };
@@ -324,7 +325,7 @@
     return FindSubsystemDevice(path, mmc_device_path, subsystem_paths);
 }
 
-bool DeviceHandler::FindScsiDevice(std::string path, std::string* scsi_device_path) const {
+bool DeviceHandler::FindScsiDevice(const std::string& path, std::string* scsi_device_path) const {
     const std::set<std::string> subsystem_paths = {
             sysfs_mount_point_ + "/bus/scsi",
     };
diff --git a/init/devices.h b/init/devices.h
index 8b6cf6c..67a3d00 100644
--- a/init/devices.h
+++ b/init/devices.h
@@ -149,9 +149,9 @@
     BlockDeviceInfo GetBlockDeviceInfo(const std::string& uevent_path) const;
     bool FindSubsystemDevice(std::string path, std::string* device_path,
                              const std::set<std::string>& subsystem_paths) const;
-    bool FindPlatformDevice(std::string path, std::string* platform_device_path) const;
-    bool FindMmcDevice(std::string path, std::string* mmc_device_path) const;
-    bool FindScsiDevice(std::string path, std::string* scsi_device_path) const;
+    bool FindPlatformDevice(const std::string& path, std::string* platform_device_path) const;
+    bool FindMmcDevice(const std::string& path, std::string* mmc_device_path) const;
+    bool FindScsiDevice(const std::string& path, std::string* scsi_device_path) const;
     std::tuple<mode_t, uid_t, gid_t> GetDevicePermissions(
         const std::string& path, const std::vector<std::string>& links) const;
     void MakeDevice(const std::string& path, bool block, int major, int minor,