fix(nvs): Improved lockig mechanism for initialization phase

components/nvs_flash/src/nvs_platform.cpp

@@ -0,0 +1,50 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include "nvs_platform.hpp"
+
+using namespace nvs;
+
+#ifdef LINUX_TARGET
+Lock::Lock() {}
+Lock::~Lock() {}
+esp_err_t nvs::Lock::init() {return ESP_OK;}
+void Lock::uninit() {}
+#else
+
+#include "sys/lock.h"
+
+Lock::Lock()
+{
+    // Newlib implementation ensures that even if mSemaphore was 0, it gets initialized.
+    // Locks mSemaphore
+    _lock_acquire(&mSemaphore);
+}
+
+Lock::~Lock()
+{
+    // Unlocks mSemaphore
+    _lock_release(&mSemaphore);
+}
+
+esp_err_t Lock::init()
+{
+    // Let postpone initialization to the Lock::Lock.
+    // It is designed to lazy initialize the semaphore in a properly guarded critical section
+    return ESP_OK;
+}
+
+void Lock::uninit()
+{
+    // Uninitializes mSemaphore. Please be aware that uninitialization of semaphore shared and held by another thread
+    // can cause undefined behavior
+    if (mSemaphore) {
+        _lock_close(&mSemaphore);
+    }
+}
+
+_lock_t Lock::mSemaphore = 0;
+
+#endif