diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index e95d9143478557b2fc12f1145d75e4adcbe90ec2..c10fc15bf8510023e41c35ba32175540f5dbd1a8 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -185,6 +185,7 @@
 
 enum mos7840_flag {
 	MOS7840_FLAG_CTRL_BUSY,
+	MOS7840_FLAG_LED_BUSY,
 };
 
 static const struct usb_device_id id_table[] = {
@@ -240,9 +241,10 @@ struct moschip_port {
 
 	/* For device(s) with LED indicator */
 	bool has_led;
-	bool led_flag;
 	struct timer_list led_timer1;	/* Timer for LED on */
 	struct timer_list led_timer2;	/* Timer for LED off */
+	struct urb *led_urb;
+	struct usb_ctrlrequest *led_dr;
 
 	unsigned long flags;
 };
@@ -535,7 +537,7 @@ static void mos7840_set_led_async(struct moschip_port *mcs, __u16 wval,
 				__u16 reg)
 {
 	struct usb_device *dev = mcs->port->serial->dev;
-	struct usb_ctrlrequest *dr = mcs->dr;
+	struct usb_ctrlrequest *dr = mcs->led_dr;
 
 	dr->bRequestType = MCS_WR_RTYPE;
 	dr->bRequest = MCS_WRREQ;
@@ -543,10 +545,10 @@ static void mos7840_set_led_async(struct moschip_port *mcs, __u16 wval,
 	dr->wIndex = cpu_to_le16(reg);
 	dr->wLength = cpu_to_le16(0);
 
-	usb_fill_control_urb(mcs->control_urb, dev, usb_sndctrlpipe(dev, 0),
+	usb_fill_control_urb(mcs->led_urb, dev, usb_sndctrlpipe(dev, 0),
 		(unsigned char *)dr, NULL, 0, mos7840_set_led_callback, NULL);
 
-	usb_submit_urb(mcs->control_urb, GFP_ATOMIC);
+	usb_submit_urb(mcs->led_urb, GFP_ATOMIC);
 }
 
 static void mos7840_set_led_sync(struct usb_serial_port *port, __u16 reg,
@@ -572,7 +574,19 @@ static void mos7840_led_flag_off(unsigned long arg)
 {
 	struct moschip_port *mcs = (struct moschip_port *) arg;
 
-	mcs->led_flag = false;
+	clear_bit_unlock(MOS7840_FLAG_LED_BUSY, &mcs->flags);
+}
+
+static void mos7840_led_activity(struct usb_serial_port *port)
+{
+	struct moschip_port *mos7840_port = usb_get_serial_port_data(port);
+
+	if (test_and_set_bit_lock(MOS7840_FLAG_LED_BUSY, &mos7840_port->flags))
+		return;
+
+	mos7840_set_led_async(mos7840_port, 0x0301, MODEM_CONTROL_REGISTER);
+	mod_timer(&mos7840_port->led_timer1,
+				jiffies + msecs_to_jiffies(LED_ON_MS));
 }
 
 /*****************************************************************************
@@ -770,14 +784,8 @@ static void mos7840_bulk_in_callback(struct urb *urb)
 		return;
 	}
 
-	/* Turn on LED */
-	if (mos7840_port->has_led && !mos7840_port->led_flag) {
-		mos7840_port->led_flag = true;
-		mos7840_set_led_async(mos7840_port, 0x0301,
-					MODEM_CONTROL_REGISTER);
-		mod_timer(&mos7840_port->led_timer1,
-				jiffies + msecs_to_jiffies(LED_ON_MS));
-	}
+	if (mos7840_port->has_led)
+		mos7840_led_activity(port);
 
 	mos7840_port->read_urb_busy = true;
 	retval = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
@@ -1454,13 +1462,8 @@ static int mos7840_write(struct tty_struct *tty, struct usb_serial_port *port,
 	data1 = urb->transfer_buffer;
 	dev_dbg(&port->dev, "bulkout endpoint is %d\n", port->bulk_out_endpointAddress);
 
-	/* Turn on LED */
-	if (mos7840_port->has_led && !mos7840_port->led_flag) {
-		mos7840_port->led_flag = true;
-		mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0301);
-		mod_timer(&mos7840_port->led_timer1,
-				jiffies + msecs_to_jiffies(LED_ON_MS));
-	}
+	if (mos7840_port->has_led)
+		mos7840_led_activity(port);
 
 	/* send it down the pipe */
 	status = usb_submit_urb(urb, GFP_ATOMIC);
@@ -2412,6 +2415,14 @@ static int mos7840_port_probe(struct usb_serial_port *port)
 	if (device_type == MOSCHIP_DEVICE_ID_7810) {
 		mos7840_port->has_led = true;
 
+		mos7840_port->led_urb = usb_alloc_urb(0, GFP_KERNEL);
+		mos7840_port->led_dr = kmalloc(sizeof(*mos7840_port->led_dr),
+								GFP_KERNEL);
+		if (!mos7840_port->led_urb || !mos7840_port->led_dr) {
+			status = -ENOMEM;
+			goto error;
+		}
+
 		init_timer(&mos7840_port->led_timer1);
 		mos7840_port->led_timer1.function = mos7840_led_off;
 		mos7840_port->led_timer1.expires =
@@ -2424,8 +2435,6 @@ static int mos7840_port_probe(struct usb_serial_port *port)
 			jiffies + msecs_to_jiffies(LED_OFF_MS);
 		mos7840_port->led_timer2.data = (unsigned long)mos7840_port;
 
-		mos7840_port->led_flag = false;
-
 		/* Turn off LED */
 		mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0300);
 	}
@@ -2447,6 +2456,8 @@ static int mos7840_port_probe(struct usb_serial_port *port)
 	}
 	return 0;
 error:
+	kfree(mos7840_port->led_dr);
+	usb_free_urb(mos7840_port->led_urb);
 	kfree(mos7840_port->dr);
 	kfree(mos7840_port->ctrl_buf);
 	usb_free_urb(mos7840_port->control_urb);
@@ -2467,6 +2478,10 @@ static int mos7840_port_remove(struct usb_serial_port *port)
 
 		del_timer_sync(&mos7840_port->led_timer1);
 		del_timer_sync(&mos7840_port->led_timer2);
+
+		usb_kill_urb(mos7840_port->led_urb);
+		usb_free_urb(mos7840_port->led_urb);
+		kfree(mos7840_port->led_dr);
 	}
 	usb_kill_urb(mos7840_port->control_urb);
 	usb_free_urb(mos7840_port->control_urb);