diff --git a/backend/Backend.cpp b/backend/Backend.cpp
index 887eb0e..15a9ff1 100644
--- a/backend/Backend.cpp
+++ b/backend/Backend.cpp
@@ -36,7 +36,8 @@
   if (avail_planes < display->layers().size())
     avail_planes--;
 
-  std::map<uint32_t, DrmHwcTwo::HwcLayer *> z_map, z_map_tmp;
+  std::map<uint32_t, DrmHwcTwo::HwcLayer *> z_map;
+  std::map<uint32_t, DrmHwcTwo::HwcLayer *> z_map_tmp;
   uint32_t z_index = 0;
   // First create a map of layers and z_order values
   for (std::pair<const hwc2_layer_t, DrmHwcTwo::HwcLayer> &l :
@@ -49,7 +50,8 @@
   uint32_t total_pixops = display->CalcPixOps(z_map, 0, z_map.size());
   uint32_t gpu_pixops = 0;
 
-  int client_start = -1, client_size = 0;
+  int client_start = -1;
+  size_t client_size = 0;
 
   if (display->compositor().ShouldFlattenOnClient()) {
     client_start = 0;
@@ -58,17 +60,18 @@
   } else {
     std::tie(client_start, client_size) = GetClientLayers(display, z_map);
 
-    int extra_client = (z_map.size() - client_size) - avail_planes;
+    size_t extra_client = (z_map.size() - client_size) - avail_planes;
     if (extra_client > 0) {
-      int start = 0, steps;
+      int start = 0;
+      size_t steps;
       if (client_size != 0) {
-        int prepend = std::min(client_start, extra_client);
-        int append = std::min(int(z_map.size() - (client_start + client_size)),
-                              extra_client);
-        start = client_start - prepend;
+        size_t prepend = std::min((size_t)client_start, extra_client);
+        size_t append = std::min(z_map.size() - (client_start + client_size),
+                                 extra_client);
+        start = client_start - (int)prepend;
         client_size += extra_client;
         steps = 1 + std::min(std::min(append, prepend),
-                             int(z_map.size()) - (start + client_size));
+                             z_map.size() - (start + client_size));
       } else {
         client_size = extra_client;
         steps = 1 + z_map.size() - extra_client;
@@ -107,15 +110,16 @@
   return *num_types ? HWC2::Error::HasChanges : HWC2::Error::None;
 }
 
-std::tuple<int, int> Backend::GetClientLayers(
+std::tuple<int, size_t> Backend::GetClientLayers(
     DrmHwcTwo::HwcDisplay *display,
     const std::map<uint32_t, DrmHwcTwo::HwcLayer *> &z_map) {
-  int client_start = -1, client_size = 0;
+  int client_start = -1;
+  size_t client_size = 0;
 
-  for (auto & [ z_order, layer ] : z_map) {
+  for (auto &[z_order, layer] : z_map) {
     if (IsClientLayer(display, layer)) {
       if (client_start < 0)
-        client_start = z_order;
+        client_start = (int)z_order;
       client_size = (z_order - client_start) + 1;
     }
   }
diff --git a/backend/Backend.h b/backend/Backend.h
index 898fece..2725809 100644
--- a/backend/Backend.h
+++ b/backend/Backend.h
@@ -27,7 +27,7 @@
   virtual HWC2::Error ValidateDisplay(DrmHwcTwo::HwcDisplay *display,
                                       uint32_t *num_types,
                                       uint32_t *num_requests);
-  virtual std::tuple<int, int> GetClientLayers(
+  virtual std::tuple<int, size_t> GetClientLayers(
       DrmHwcTwo::HwcDisplay *display,
       const std::map<uint32_t, DrmHwcTwo::HwcLayer *> &z_map);
   virtual bool IsClientLayer(DrmHwcTwo::HwcDisplay *display,
diff --git a/backend/BackendManager.cpp b/backend/BackendManager.cpp
index 0bacdcd..a346d46 100644
--- a/backend/BackendManager.cpp
+++ b/backend/BackendManager.cpp
@@ -23,7 +23,7 @@
 
 namespace android {
 
-const std::vector<std::string> BackendManager::client_devices_ = {
+const std::vector<std::string> BackendManager::kClientDevices = {
     "kirin",
     "mediatek-drm",
 };
@@ -45,7 +45,7 @@
   char backend_override[PROPERTY_VALUE_MAX];
   property_get("vendor.hwc.backend_override", backend_override,
                driver_name.c_str());
-  std::string backend_name(std::move(backend_override));
+  std::string backend_name(backend_override);
 
   display->set_backend(GetBackendByName(backend_name));
   if (!display->backend()) {
@@ -63,15 +63,15 @@
 }
 
 std::unique_ptr<Backend> BackendManager::GetBackendByName(std::string &name) {
-  if (!available_backends_.size()) {
+  if (available_backends_.empty()) {
     ALOGE("No backends are specified");
     return nullptr;
   }
 
   auto it = available_backends_.find(name);
   if (it == available_backends_.end()) {
-    auto it = std::find(client_devices_.begin(), client_devices_.end(), name);
-    name = it == client_devices_.end() ? "generic" : "client";
+    auto it = std::find(kClientDevices.begin(), kClientDevices.end(), name);
+    name = it == kClientDevices.end() ? "generic" : "client";
   }
 
   return available_backends_[name]();
diff --git a/backend/BackendManager.h b/backend/BackendManager.h
index e86c098..9b314db 100644
--- a/backend/BackendManager.h
+++ b/backend/BackendManager.h
@@ -48,7 +48,7 @@
  private:
   BackendManager() = default;
 
-  static const std::vector<std::string> client_devices_;
+  static const std::vector<std::string> kClientDevices;
 
   std::map<std::string, backend_constructor_t> available_backends_;
 };