Commit fe88c648 authored Sep 09, 2020 by Johan Hovold Committed by Greg Kroah-Hartman Sep 16, 2020

serial: core: fix port-lock initialisation

Commit f743061a ("serial: core: Initialise spin lock before use in
uart_configure_port()") tried to work around a breakage introduced by
commit a3cb39d2 ("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: f743061a ("serial: core: Initialise spin lock before use in uart_configure_port()")
Fixes: a3cb39d2 ("serial: core: Allow detach and attach serial device for console")
Cc: stable <stable@vger.kernel.org>     # 5.7
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200909143101.15389-2-johan@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent f75aef39

drivers/tty/serial/serial_core.c

+6 −8

Original line number	Diff line number	Diff line
		@@ -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);

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