diff --git a/audio/aidl/default/downmix/DownmixSw.cpp b/audio/aidl/default/downmix/DownmixSw.cpp
index ce5fe20..19ab2e8 100644
--- a/audio/aidl/default/downmix/DownmixSw.cpp
+++ b/audio/aidl/default/downmix/DownmixSw.cpp
@@ -144,10 +144,6 @@
     return mContext;
 }
 
-std::shared_ptr<EffectContext> DownmixSw::getContext() {
-    return mContext;
-}
-
 RetCode DownmixSw::releaseContext() {
     if (mContext) {
         mContext.reset();
diff --git a/audio/aidl/default/downmix/DownmixSw.h b/audio/aidl/default/downmix/DownmixSw.h
index 3f8a09b..1a9f0f0 100644
--- a/audio/aidl/default/downmix/DownmixSw.h
+++ b/audio/aidl/default/downmix/DownmixSw.h
@@ -55,20 +55,23 @@
     }
 
     ndk::ScopedAStatus getDescriptor(Descriptor* _aidl_return) override;
-    ndk::ScopedAStatus setParameterSpecific(const Parameter::Specific& specific) override;
-    ndk::ScopedAStatus getParameterSpecific(const Parameter::Id& id,
-                                            Parameter::Specific* specific) override;
+    ndk::ScopedAStatus setParameterSpecific(const Parameter::Specific& specific)
+            REQUIRES(mImplMutex) override;
+    ndk::ScopedAStatus getParameterSpecific(const Parameter::Id& id, Parameter::Specific* specific)
+            REQUIRES(mImplMutex) override;
 
-    std::shared_ptr<EffectContext> createContext(const Parameter::Common& common) override;
-    std::shared_ptr<EffectContext> getContext() override;
-    RetCode releaseContext() override;
+    std::shared_ptr<EffectContext> createContext(const Parameter::Common& common)
+            REQUIRES(mImplMutex) override;
+    RetCode releaseContext() REQUIRES(mImplMutex) override;
 
     std::string getEffectName() override { return kEffectName; };
-    IEffect::Status effectProcessImpl(float* in, float* out, int sample) override;
+    IEffect::Status effectProcessImpl(float* in, float* out, int sample)
+            REQUIRES(mImplMutex) override;
 
   private:
-    std::shared_ptr<DownmixSwContext> mContext;
+    std::shared_ptr<DownmixSwContext> mContext GUARDED_BY(mImplMutex);
 
-    ndk::ScopedAStatus getParameterDownmix(const Downmix::Tag& tag, Parameter::Specific* specific);
+    ndk::ScopedAStatus getParameterDownmix(const Downmix::Tag& tag, Parameter::Specific* specific)
+            REQUIRES(mImplMutex);
 };
 }  // namespace aidl::android::hardware::audio::effect