[logging] fix dynamic log level (#7016)

Set mLoggingLevel as static member.

src/core/api/logging_api.cpp

@@ -41,8 +41,8 @@ using namespace ot;
 
 otLogLevel otLoggingGetLevel(void)
 {
-#if OPENTHREAD_CONFIG_LOG_LEVEL_DYNAMIC_ENABLE && !OPENTHREAD_CONFIG_MULTIPLE_INSTANCE_ENABLE
-    return Instance::Get().GetLogLevel();
+#if OPENTHREAD_CONFIG_LOG_LEVEL_DYNAMIC_ENABLE
+    return Instance::GetLogLevel();
 #else
     return static_cast<otLogLevel>(OPENTHREAD_CONFIG_LOG_LEVEL);
 #endif
@@ -55,7 +55,7 @@ otError otLoggingSetLevel(otLogLevel aLogLevel)
 
     if (aLogLevel <= OT_LOG_LEVEL_DEBG && aLogLevel >= OT_LOG_LEVEL_NONE)
     {
-        Instance::Get().SetLogLevel(aLogLevel);
+        Instance::SetLogLevel(aLogLevel);
     }
     else
     {

src/core/common/instance.cpp

@@ -58,6 +58,10 @@ bool Instance::sDnsNameCompressionEnabled = true;
 #endif
 #endif
 
+#if OPENTHREAD_CONFIG_LOG_LEVEL_DYNAMIC_ENABLE
+otLogLevel Instance::sLogLevel = static_cast<otLogLevel>(OPENTHREAD_CONFIG_LOG_LEVEL_INIT);
+#endif
+
 Instance::Instance(void)
     : mTimerMilliScheduler(*this)
 #if OPENTHREAD_CONFIG_PLATFORM_USEC_TIMER_ENABLE
@@ -109,9 +113,6 @@ Instance::Instance(void)
 #if OPENTHREAD_RADIO || OPENTHREAD_CONFIG_LINK_RAW_ENABLE
     , mLinkRaw(*this)
 #endif
-#if OPENTHREAD_CONFIG_LOG_LEVEL_DYNAMIC_ENABLE
-    , mLogLevel(static_cast<otLogLevel>(OPENTHREAD_CONFIG_LOG_LEVEL_INIT))
-#endif
 #if OPENTHREAD_ENABLE_VENDOR_EXTENSION
     , mExtension(Extension::ExtensionBase::Init(*this))
 #endif

src/core/common/instance.hpp

@@ -208,10 +208,10 @@ public:
      * @returns The log level.
      *
      */
-    otLogLevel GetLogLevel(void) const
+    static otLogLevel GetLogLevel(void)
 #if OPENTHREAD_CONFIG_LOG_LEVEL_DYNAMIC_ENABLE
     {
-        return mLogLevel;
+        return sLogLevel;
     }
 #else
     {
@@ -226,10 +226,10 @@ public:
      * @param[in] aLogLevel  A log level.
      *
      */
-    void SetLogLevel(otLogLevel aLogLevel)
+    static void SetLogLevel(otLogLevel aLogLevel)
     {
         OT_ASSERT(aLogLevel <= OT_LOG_LEVEL_DEBG && aLogLevel >= OT_LOG_LEVEL_NONE);
-        mLogLevel = aLogLevel;
+        sLogLevel = aLogLevel;
     }
 #endif
 
@@ -429,7 +429,7 @@ private:
 #endif // OPENTHREAD_RADIO || OPENTHREAD_CONFIG_LINK_RAW_ENABLE
 
 #if OPENTHREAD_CONFIG_LOG_LEVEL_DYNAMIC_ENABLE
-    otLogLevel mLogLevel;
+    static otLogLevel sLogLevel;
 #endif
 #if OPENTHREAD_ENABLE_VENDOR_EXTENSION
     Extension::ExtensionBase &mExtension;

src/core/thread/mesh_forwarder.cpp

@@ -1816,7 +1816,7 @@ void MeshForwarder::LogMessage(MessageAction       aAction,
         break;
     }
 
-    VerifyOrExit(GetInstance().GetLogLevel() >= logLevel);
+    VerifyOrExit(Instance::GetLogLevel() >= logLevel);
 
     switch (aMessage.GetType())
     {