libs/libc: remove unnecessary flockfile to improve performance

modify lib_wrflush/lib_rdflush/lib_ffulsh to unlocked version

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>

libs/libc/stdio/lib_wrflush_unlocked.c

@@ -0,0 +1,99 @@
+/****************************************************************************
+ * libs/libc/stdio/lib_wrflush_unlocked.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdbool.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "libc.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lib_wrflush_unlocked
+ *
+ * Description:
+ *   This is simply a version of fflush that does not report an error if
+ *   the file is not open for writing.
+ *
+ ****************************************************************************/
+
+int lib_wrflush_unlocked(FAR FILE *stream)
+{
+#ifndef CONFIG_STDIO_DISABLE_BUFFERING
+  /* Verify that we were passed a valid (i.e., non-NULL) stream */
+
+#ifdef CONFIG_DEBUG_FEATURES
+  if (stream == NULL)
+    {
+      return -EINVAL;
+    }
+#endif
+
+  /* Do nothing if there is no I/O buffer */
+
+  if (stream->fs_bufstart == NULL)
+    {
+      return OK;
+    }
+
+  /* Verify that the stream is opened for writing... lib_fflush will
+   * return an error if it is called for a stream that is not opened for
+   * writing.  Check that first so that this function will not fail in
+   * that case.
+   */
+
+  if ((stream->fs_oflags & O_WROK) == 0)
+    {
+      /* Report that the success was successful if we attempt to flush a
+       * read-only stream.
+       */
+
+      return OK;
+    }
+
+  /* Flush the stream.   Return success if there is no buffered write data
+   * -- i.e., that the stream is opened for writing and  that all of the
+   * buffered write data was successfully flushed by lib_fflush().
+   */
+
+  return lib_fflush_unlocked(stream, true);
+
+#else
+  /* Verify that we were passed a valid (i.e., non-NULL) stream */
+
+#ifdef CONFIG_DEBUG_FEATURES
+  if (!stream)
+    {
+      return -EINVAL;
+    }
+#endif
+
+  return OK;
+#endif
+}