Revert early HTTP port reservation (#17754, #19805) (#20468)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

python/sglang/utils.py

@@ -409,61 +409,6 @@ def reserve_port(host, start=30000, end=40000):
     raise RuntimeError("No free port available.")
 
 
-def _prebind_listening_socket(host: str, port: int) -> socket.socket:
-    """
-    Create and bind a server socket to reserve the port before model loading.
-
-    This prevents port conflicts that could occur if another process (e.g., a
-    subprocess spawned during model loading) binds to the same port before the
-    HTTP server starts. By binding early, we ensure the port is available and
-    reserved for the HTTP server. The socket is intentionally not put into
-    listening mode here to avoid accepting probe connections before uvicorn is
-    ready to serve requests.
-
-    Args:
-        host: The host address to bind to.
-        port: The port number to bind to.
-
-    Returns:
-        A bound socket object.
-
-    Raises:
-        RuntimeError: If the port is already in use or permission is denied.
-    """
-    import errno
-
-    from sglang.srt.utils.network import NetworkAddress
-
-    # Determine socket family based on address type
-    na = NetworkAddress(host or "0.0.0.0", port)
-    sock = socket.socket(family=na.family, type=socket.SOCK_STREAM)
-    # SO_REUSEADDR: Allows binding to a port in TIME_WAIT state
-    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-
-    try:
-        sock.bind(na.to_bind_tuple())
-        sock.set_inheritable(True)
-        logger.info(f"Successfully reserved port {port} on host '{na.host}'")
-    except OSError as e:
-        sock.close()
-        if e.errno == errno.EADDRINUSE:
-            raise RuntimeError(
-                f"Port {port} is already in use on host '{na.host}'. "
-                f"Please choose a different port with --port or stop the process using this port. "
-                f"You can find the process using: lsof -i :{port} or netstat -tlnp | grep {port}"
-            ) from e
-        elif e.errno == errno.EACCES:
-            raise RuntimeError(
-                f"Permission denied when trying to bind to port {port}. "
-                f"Ports below 1024 require root/sudo privileges. "
-                f"Consider using a port >= 1024 (e.g., --port 8000) or run with sudo."
-            ) from e
-        else:
-            raise RuntimeError(f"Failed to bind to {na}: {e}") from e
-
-    return sock
-
-
 def release_port(lock_socket):
     """
     Release the reserved port by closing the lock socket.