Message-ID: <b23d566c-09dc-7374-cc87-0ad4660e8b2e@linux.intel.com>
Date: Wed, 11 Jun 2025 14:13:35 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
    linux-serial <linux-serial@...r.kernel.org>, 
    LKML <linux-kernel@...r.kernel.org>, Karsten Keil <isdn@...ux-pingi.de>, 
    David Lin <dtwlin@...il.com>, Johan Hovold <johan@...nel.org>, 
    Alex Elder <elder@...nel.org>, Oliver Neukum <oneukum@...e.com>, 
    Marcel Holtmann <marcel@...tmann.org>, 
    Johan Hedberg <johan.hedberg@...il.com>, 
    Luiz Augusto von Dentz <luiz.dentz@...il.com>, 
    Netdev <netdev@...r.kernel.org>, greybus-dev@...ts.linaro.org, 
    linux-staging@...ts.linux.dev, linux-usb@...r.kernel.org, 
    linux-bluetooth@...r.kernel.org
Subject: Re: [PATCH 01/33] tty: introduce and use tty_port_tty_vhangup()
 helper

On Wed, 11 Jun 2025, Jiri Slaby (SUSE) wrote:

> 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@...nel.org>
> Cc: Karsten Keil <isdn@...ux-pingi.de>
> Cc: David Lin <dtwlin@...il.com>
> Cc: Johan Hovold <johan@...nel.org>
> Cc: Alex Elder <elder@...nel.org>
> Cc: Oliver Neukum <oneukum@...e.com>
> Cc: Marcel Holtmann <marcel@...tmann.org>
> Cc: Johan Hedberg <johan.hedberg@...il.com>
> Cc: Luiz Augusto von Dentz <luiz.dentz@...il.com>

Nice cleanup. I'm not sure if it's important enough to be mentioned in
Documentation/driver-api/tty/tty_port.rst .

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>

-- 
 i.

> ---
> Cc: netdev@...r.kernel.org
> Cc: greybus-dev@...ts.linaro.org
> Cc: linux-staging@...ts.linux.dev
> Cc: linux-usb@...r.kernel.org
> Cc: linux-bluetooth@...r.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 70dee9ad4bae..78e6e7748fb9 100644
> --- a/drivers/isdn/capi/capi.c
> +++ b/drivers/isdn/capi/capi.c
> @@ -306,15 +306,9 @@ 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 308ed1ca9947..10df5c37c83e 100644
> --- a/drivers/staging/greybus/uart.c
> +++ b/drivers/staging/greybus/uart.c
> @@ -916,7 +916,6 @@ 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);
> @@ -929,11 +928,7 @@ 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 1f7708a91fc6..d6485714eb0f 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -3209,7 +3209,6 @@ 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);
> @@ -3228,11 +3227,7 @@ 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 4af1fbf73f51..903eebdbe12d 100644
> --- a/drivers/tty/tty_port.c
> +++ b/drivers/tty/tty_port.c
> @@ -396,15 +396,19 @@ 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 c2ecfa3c8349..f9171fbedf5c 100644
> --- a/drivers/usb/class/cdc-acm.c
> +++ b/drivers/usb/class/cdc-acm.c
> @@ -1571,7 +1571,6 @@ 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 */
> @@ -1598,11 +1597,7 @@ 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 7266558d823a..c78ff40b1e5f 100644
> --- a/drivers/usb/serial/usb-serial.c
> +++ b/drivers/usb/serial/usb-serial.c
> @@ -1176,7 +1176,6 @@ 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)
> @@ -1191,11 +1190,7 @@ 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 08f89a598366..021f9a8415c0 100644
> --- a/include/linux/tty_port.h
> +++ b/include/linux/tty_port.h
> @@ -232,7 +232,7 @@ 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);
> @@ -251,4 +251,14 @@ 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 21a5b5535ebc..827dfbe66085 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);
> 

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