Commit f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") tried to work around a breakage introduced by commit a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") by adding a second initialisation of the port lock when registering the port.

As reported by the build robots [1], this doesn't really solve the regression introduced by the console-detach changes and also adds a second redundant initialisation of the lock for normal ports.

Start cleaning up this mess by removing the redundant initialisation and making sure that the port lock is again initialised once-only for ports that aren't already in use as a console.

[1] https://lore.kernel.org/r/20200802054852.GR23458@shao2-debian

Fixes: f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Cc: stable stable@vger.kernel.org # 5.7 Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Signed-off-by: Johan Hovold johan@kernel.org --- drivers/tty/serial/serial_core.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index f797c971cd82..53b79e1fcbc8 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2378,13 +2378,6 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, /* Power up port for set_mctrl() */ uart_change_pm(state, UART_PM_STATE_ON);

- /* - * If this driver supports console, and it hasn't been - * successfully registered yet, initialise spin lock for it. - */ - if (port->cons && !(port->cons->flags & CON_ENABLED)) - __uart_port_spin_lock_init(port); - /* * Ensure that the modem control lines are de-activated. * keep the DTR setting that is set in uart_set_options() @@ -2900,7 +2893,12 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) goto out; }

- uart_port_spin_lock_init(uport); + /* + * If this port is in use as a console then the spinlock is already + * initialised. + */ + if (!uart_console_enabled(uport)) + __uart_port_spin_lock_init(uport);

if (uport->cons && uport->dev) of_console_check(uport->dev->of_node, uport->cons->name, uport->line);