[PATCH 6.6.y 1/2] tty: introduce and use tty_port_tty_vhangup() helper

[Sasha Levin <sashal@kernel.org>]

From: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>

[ Upstream commit 2b5eac0f8c6e79bc152c8804f9f88d16717013ab ]

This code (tty_get -> vhangup -> tty_put) is repeated on few places.
Introduce a helper similar to tty_port_tty_hangup() (asynchronous) to
handle even vhangup (synchronous).

And use it on those places.

In fact, reuse the tty_port_tty_hangup()'s code and call tty_vhangup()
depending on a new bool parameter.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: David Lin <dtwlin@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250611100319.186924-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 74098cc06e75 ("xhci: dbgtty: fix device unregister: fixup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/isdn/capi/capi.c         |  8 +-------
 drivers/staging/greybus/uart.c   |  7 +------
 drivers/tty/serial/serial_core.c |  7 +------
 drivers/tty/tty_port.c           | 12 ++++++++----
 drivers/usb/class/cdc-acm.c      |  7 +------
 drivers/usb/serial/usb-serial.c  |  7 +------
 include/linux/tty_port.h         | 12 +++++++++++-
 net/bluetooth/rfcomm/tty.c       |  7 +------
 8 files changed, 25 insertions(+), 42 deletions(-)

diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 2f3789515445..11a1a26f7510 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -304,15 +304,9 @@ static void capincci_alloc_minor(struct capidev *cdev, struct capincci *np)
 static void capincci_free_minor(struct capincci *np)
 {
 	struct capiminor *mp = np->minorp;
-	struct tty_struct *tty;
 
 	if (mp) {
-		tty = tty_port_tty_get(&mp->port);
-		if (tty) {
-			tty_vhangup(tty);
-			tty_kref_put(tty);
-		}
-
+		tty_port_tty_vhangup(&mp->port);
 		capiminor_free(mp);
 	}
 }
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index 999ce613dca8..526573556cda 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -914,7 +914,6 @@ static void gb_uart_remove(struct gbphy_device *gbphy_dev)
 {
 	struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
 	struct gb_connection *connection = gb_tty->connection;
-	struct tty_struct *tty;
 	int ret;
 
 	ret = gbphy_runtime_get_sync(gbphy_dev);
@@ -927,11 +926,7 @@ static void gb_uart_remove(struct gbphy_device *gbphy_dev)
 	wake_up_all(&gb_tty->wioctl);
 	mutex_unlock(&gb_tty->mutex);
 
-	tty = tty_port_tty_get(&gb_tty->port);
-	if (tty) {
-		tty_vhangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(&gb_tty->port);
 
 	gb_connection_disable_rx(connection);
 	tty_unregister_device(gb_tty_driver, gb_tty->minor);
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 8ff0efac6aa0..c3a51bd59ff7 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3250,7 +3250,6 @@ static void serial_core_remove_one_port(struct uart_driver *drv,
 	struct uart_state *state = drv->state + uport->line;
 	struct tty_port *port = &state->port;
 	struct uart_port *uart_port;
-	struct tty_struct *tty;
 
 	mutex_lock(&port->mutex);
 	uart_port = uart_port_check(state);
@@ -3269,11 +3268,7 @@ static void serial_core_remove_one_port(struct uart_driver *drv,
 	 */
 	tty_port_unregister_device(port, drv->tty_driver, uport->line);
 
-	tty = tty_port_tty_get(port);
-	if (tty) {
-		tty_vhangup(port->tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(port);
 
 	/*
 	 * If the port is used as a console, unregister it
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 624d104bd145..eb51d1f10d56 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -414,15 +414,19 @@ EXPORT_SYMBOL(tty_port_hangup);
  * @port: tty port
  * @check_clocal: hang only ttys with %CLOCAL unset?
  */
-void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
+void __tty_port_tty_hangup(struct tty_port *port, bool check_clocal, bool async)
 {
 	struct tty_struct *tty = tty_port_tty_get(port);
 
-	if (tty && (!check_clocal || !C_CLOCAL(tty)))
-		tty_hangup(tty);
+	if (tty && (!check_clocal || !C_CLOCAL(tty))) {
+		if (async)
+			tty_hangup(tty);
+		else
+			tty_vhangup(tty);
+	}
 	tty_kref_put(tty);
 }
-EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
+EXPORT_SYMBOL_GPL(__tty_port_tty_hangup);
 
 /**
  * tty_port_tty_wakeup - helper to wake up a tty
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index f0c87c914149..c0c4a9415a76 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1572,7 +1572,6 @@ static int acm_probe(struct usb_interface *intf,
 static void acm_disconnect(struct usb_interface *intf)
 {
 	struct acm *acm = usb_get_intfdata(intf);
-	struct tty_struct *tty;
 	int i;
 
 	/* sibling interface is already cleaning up */
@@ -1599,11 +1598,7 @@ static void acm_disconnect(struct usb_interface *intf)
 	usb_set_intfdata(acm->data, NULL);
 	mutex_unlock(&acm->mutex);
 
-	tty = tty_port_tty_get(&acm->port);
-	if (tty) {
-		tty_vhangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(&acm->port);
 
 	cancel_delayed_work_sync(&acm->dwork);
 
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 17b09f03ef84..be81d4a2f79f 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1178,7 +1178,6 @@ static void usb_serial_disconnect(struct usb_interface *interface)
 	struct usb_serial *serial = usb_get_intfdata(interface);
 	struct device *dev = &interface->dev;
 	struct usb_serial_port *port;
-	struct tty_struct *tty;
 
 	/* sibling interface is cleaning up */
 	if (!serial)
@@ -1193,11 +1192,7 @@ static void usb_serial_disconnect(struct usb_interface *interface)
 
 	for (i = 0; i < serial->num_ports; ++i) {
 		port = serial->port[i];
-		tty = tty_port_tty_get(&port->port);
-		if (tty) {
-			tty_vhangup(tty);
-			tty_kref_put(tty);
-		}
+		tty_port_tty_vhangup(&port->port);
 		usb_serial_port_poison_urbs(port);
 		wake_up_interruptible(&port->port.delta_msr_wait);
 		cancel_work_sync(&port->work);
diff --git a/include/linux/tty_port.h b/include/linux/tty_port.h
index 6b367eb17979..bd025c6f3a20 100644
--- a/include/linux/tty_port.h
+++ b/include/linux/tty_port.h
@@ -235,7 +235,7 @@ bool tty_port_carrier_raised(struct tty_port *port);
 void tty_port_raise_dtr_rts(struct tty_port *port);
 void tty_port_lower_dtr_rts(struct tty_port *port);
 void tty_port_hangup(struct tty_port *port);
-void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
+void __tty_port_tty_hangup(struct tty_port *port, bool check_clocal, bool async);
 void tty_port_tty_wakeup(struct tty_port *port);
 int tty_port_block_til_ready(struct tty_port *port, struct tty_struct *tty,
 		struct file *filp);
@@ -254,4 +254,14 @@ static inline int tty_port_users(struct tty_port *port)
 	return port->count + port->blocked_open;
 }
 
+static inline void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
+{
+	__tty_port_tty_hangup(port, check_clocal, true);
+}
+
+static inline void tty_port_tty_vhangup(struct tty_port *port)
+{
+	__tty_port_tty_hangup(port, false, false);
+}
+
 #endif
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index e258ca191470..912e37cb8310 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -438,7 +438,6 @@ static int __rfcomm_release_dev(void __user *arg)
 {
 	struct rfcomm_dev_req req;
 	struct rfcomm_dev *dev;
-	struct tty_struct *tty;
 
 	if (copy_from_user(&req, arg, sizeof(req)))
 		return -EFAULT;
@@ -464,11 +463,7 @@ static int __rfcomm_release_dev(void __user *arg)
 		rfcomm_dlc_close(dev->dlc, 0);
 
 	/* Shut down TTY synchronously before freeing rfcomm_dev */
-	tty = tty_port_tty_get(&dev->port);
-	if (tty) {
-		tty_vhangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(&dev->port);
 
 	if (!test_bit(RFCOMM_TTY_OWNED, &dev->status))
 		tty_port_put(&dev->port);
-- 
2.51.0