docs: kdoc: avoid error_count overflows

The glibc library limits the return code to 8 bits. We need to
stick to this limit when using sys.exit(error_count).

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <233d1674db99ed8feb405a2f781de350f0fba0ac.1768823489.git.mchehab+huawei@kernel.org>

Author: mchehab

scripts/kernel-doc.py

@@ -116,6 +116,8 @@
 
 sys.path.insert(0, os.path.join(SRC_DIR, LIB_DIR))
 
+WERROR_RETURN_CODE = 3
+
 DESC = """
 Read C language source or header FILEs, extract embedded documentation comments,
 and print formatted documentation to standard output.
@@ -176,7 +178,21 @@ def format(self, record):
         return logging.Formatter.format(self, record)
 
 def main():
-    """Main program"""
+    """
+    Main program.
+
+    By default, the return value is:
+
+    - 0: success or Python version is not compatible with
+      kernel-doc.  If -Werror is not used, it will also
+      return 0 if there are issues at kernel-doc markups;
+
+    - 1: an abnormal condition happened;
+
+    - 2: argparse issued an error;
+
+    - 3: -Werror is used, and one or more unfiltered parse warnings happened.
+    """
 
     parser = argparse.ArgumentParser(formatter_class=argparse.RawTextHelpFormatter,
                                      description=DESC)
@@ -323,16 +339,12 @@ def main():
 
     if args.werror:
         print("%s warnings as errors" % error_count)    # pylint: disable=C0209
-        sys.exit(error_count)
+        sys.exit(WERROR_RETURN_CODE)
 
     if args.verbose:
         print("%s errors" % error_count)                # pylint: disable=C0209
 
-    if args.none:
-        sys.exit(0)
-
-    sys.exit(error_count)
-
+    sys.exit(0)
 
 # Call main method
 if __name__ == "__main__":