This is a note to let you know that I've just added the patch titled
serial: core: fix port-lock initialisation
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From fe88c6489264eaea23570dfdf03e1d3f5f47f423 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Wed, 9 Sep 2020 16:31:00 +0200
Subject: serial: core: fix port-lock initialisation
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@xxxxxxxxxxxxxxx> # 5.7
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200909143101.15389-2-johan@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
--
2.28.0
