serial: core: Remove BUG_ON(in_interrupt()) check

The usage of in_interrupt() in drivers is phased out for various
reasons.

In both exported functions where BUG_ON(in_interrupt()) is invoked,
there is a mutex_lock() afterwards. mutex_lock() contains a
might_sleep() which will already trigger a stack trace if the target
functions is called from atomic context.

Remove the BUG_ON() and add a "Context: " in the kernel-doc instead.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20210208181615.381861-3-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 7dacdb6..ba31e97 100644 (file)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2848,6 +2848,8 @@ static const struct attribute_group tty_dev_attr_group = {
  *     @drv: pointer to the uart low level driver structure for this port
  *     @uport: uart port structure to use for this port.
  *
+ *     Context: task context, might sleep
+ *
  *     This allows the driver to register its own uart_port structure
  *     with the core driver.  The main purpose is to allow the low
  *     level uart drivers to expand uart_port, rather than having yet
@@ -2861,8 +2863,6 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
        struct device *tty_dev;
        int num_groups;
 
-       BUG_ON(in_interrupt());
-
        if (uport->line >= drv->nr)
                return -EINVAL;
 
@@ -2951,6 +2951,8 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
  *     @drv: pointer to the uart low level driver structure for this port
  *     @uport: uart port structure for this port
  *
+ *     Context: task context, might sleep
+ *
  *     This unhooks (and hangs up) the specified port structure from the
  *     core driver.  No further calls will be made to the low-level code
  *     for this port.
@@ -2963,8 +2965,6 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
        struct tty_struct *tty;
        int ret = 0;
 
-       BUG_ON(in_interrupt());
-
        mutex_lock(&port_mutex);
 
        /*