FAILED: patch "[PATCH] USB: serial: f81232: fix interrupt worker not stop" failed to apply to 4.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 804dbee1e49774918339c1e5a87400988c0819e8 Mon Sep 17 00:00:00 2001
From: "Ji-Ze Hong (Peter Hong)" <hpeter@gmail.com>
Date: Tue, 30 Apr 2019 09:22:29 +0800
Subject: [PATCH] USB: serial: f81232: fix interrupt worker not stop

The F81232 will use interrupt worker to handle MSR change.
This patch will fix the issue that interrupt work should stop
in close() and suspend().

This also fixes line-status events being disabled after a suspend cycle
until the port is re-opened.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
[ johan: amend commit message ]
Fixes: 87fe5adcd8de ("USB: f81232: implement read IIR/MSR with endpoint")
Cc: stable <stable@vger.kernel.org>	# 4.1
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 0dcdcb4b2cde..dee6f2caf9b5 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -556,9 +556,12 @@ static int f81232_open(struct tty_struct *tty, struct usb_serial_port *port)
 
 static void f81232_close(struct usb_serial_port *port)
 {
+	struct f81232_private *port_priv = usb_get_serial_port_data(port);
+
 	f81232_port_disable(port);
 	usb_serial_generic_close(port);
 	usb_kill_urb(port->interrupt_in_urb);
+	flush_work(&port_priv->interrupt_work);
 }
 
 static void f81232_dtr_rts(struct usb_serial_port *port, int on)
@@ -632,6 +635,40 @@ static int f81232_port_remove(struct usb_serial_port *port)
 	return 0;
 }
 
+static int f81232_suspend(struct usb_serial *serial, pm_message_t message)
+{
+	struct usb_serial_port *port = serial->port[0];
+	struct f81232_private *port_priv = usb_get_serial_port_data(port);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
+		usb_kill_urb(port->read_urbs[i]);
+
+	usb_kill_urb(port->interrupt_in_urb);
+
+	if (port_priv)
+		flush_work(&port_priv->interrupt_work);
+
+	return 0;
+}
+
+static int f81232_resume(struct usb_serial *serial)
+{
+	struct usb_serial_port *port = serial->port[0];
+	int result;
+
+	if (tty_port_initialized(&port->port)) {
+		result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
+		if (result) {
+			dev_err(&port->dev, "submit interrupt urb failed: %d\n",
+					result);
+			return result;
+		}
+	}
+
+	return usb_serial_generic_resume(serial);
+}
+
 static struct usb_serial_driver f81232_device = {
 	.driver = {
 		.owner =	THIS_MODULE,
@@ -655,6 +692,8 @@ static struct usb_serial_driver f81232_device = {
 	.read_int_callback =	f81232_read_int_callback,
 	.port_probe =		f81232_port_probe,
 	.port_remove =		f81232_port_remove,
+	.suspend =		f81232_suspend,
+	.resume =		f81232_resume,
 };
 
 static struct usb_serial_driver * const serial_drivers[] = {