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Subject[PATCH 2/2] serial: core: Remove BUG_ON(in_interrupt()) check
Date
From: "Ahmed S. Darwish" <a.darwish@linutronix.de>

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>
---
drivers/tty/serial/serial_core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 7dacdb6a85345..62dc7b5cd60c6 100644
--- 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);

/*
--
2.30.0
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