1 files changed, 66 insertions, 349 deletions

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index a453965f9e9a..e59bfa7c8030 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * mos7720.c
  *   Controls the Moschip 7720 usb to dual port serial converter
  *
  * Copyright 2006 Moschip Semiconductor Tech. Ltd.
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 2 of the License.
- *
  * Developed by:
  * 	Vijaya Kumar <vijaykumar.gn@gmail.com>
  *	Ajay Kumar <naanuajay@yahoo.com>
@@ -82,14 +79,6 @@ MODULE_DEVICE_TABLE(usb, id_table);
 #define DCR_INIT_VAL       0x0c	/* SLCTIN, nINIT */
 #define ECR_INIT_VAL       0x00	/* SPP mode */
 
-struct urbtracker {
-	struct mos7715_parport  *mos_parport;
-	struct list_head        urblist_entry;
-	struct kref             ref_count;
-	struct urb              *urb;
-	struct usb_ctrlrequest	*setup;
-};
-
 enum mos7715_pp_modes {
 	SPP = 0<<5,
 	PS2 = 1<<5,      /* moschip calls this 'NIBBLE' mode */
@@ -99,12 +88,9 @@ enum mos7715_pp_modes {
 struct mos7715_parport {
 	struct parport          *pp;	       /* back to containing struct */
 	struct kref             ref_count;     /* to instance of this struct */
-	struct list_head        deferred_urbs; /* list deferred async urbs */
-	struct list_head        active_urbs;   /* list async urbs in flight */
-	spinlock_t              listlock;      /* protects list access */
 	bool                    msg_pending;   /* usb sync call pending */
 	struct completion       syncmsg_compl; /* usb sync call completed */
-	struct tasklet_struct   urb_tasklet;   /* for sending deferred urbs */
+	struct work_struct      work;          /* restore deferred writes */
 	struct usb_serial       *serial;       /* back to containing struct */
 	__u8	                shadowECR;     /* parallel port regs... */
 	__u8	                shadowDCR;
@@ -229,8 +215,10 @@ static int read_mos_reg(struct usb_serial *serial, unsigned int serial_portnum,
 	int status;
 
 	buf = kmalloc(1, GFP_KERNEL);
-	if (!buf)
+	if (!buf) {
+		*data = 0;
 		return -ENOMEM;
+	}
 
 	status = usb_control_msg(usbdev, pipe, request, requesttype, value,
 				     index, buf, 1, MOS_WDR_TIMEOUT);
@@ -268,172 +256,8 @@ static void destroy_mos_parport(struct kref *kref)
 	kfree(mos_parport);
 }
 
-static void destroy_urbtracker(struct kref *kref)
-{
-	struct urbtracker *urbtrack =
-		container_of(kref, struct urbtracker, ref_count);
-	struct mos7715_parport *mos_parport = urbtrack->mos_parport;
-
-	usb_free_urb(urbtrack->urb);
-	kfree(urbtrack->setup);
-	kfree(urbtrack);
-	kref_put(&mos_parport->ref_count, destroy_mos_parport);
-}
-
 /*
- * This runs as a tasklet when sending an urb in a non-blocking parallel
- * port callback had to be deferred because the disconnect mutex could not be
- * obtained at the time.
- */
-static void send_deferred_urbs(unsigned long _mos_parport)
-{
-	int ret_val;
-	unsigned long flags;
-	struct mos7715_parport *mos_parport = (void *)_mos_parport;
-	struct urbtracker *urbtrack, *tmp;
-	struct list_head *cursor, *next;
-	struct device *dev;
-
-	/* if release function ran, game over */
-	if (unlikely(mos_parport->serial == NULL))
-		return;
-
-	dev = &mos_parport->serial->dev->dev;
-
-	/* try again to get the mutex */
-	if (!mutex_trylock(&mos_parport->serial->disc_mutex)) {
-		dev_dbg(dev, "%s: rescheduling tasklet\n", __func__);
-		tasklet_schedule(&mos_parport->urb_tasklet);
-		return;
-	}
-
-	/* if device disconnected, game over */
-	if (unlikely(mos_parport->serial->disconnected)) {
-		mutex_unlock(&mos_parport->serial->disc_mutex);
-		return;
-	}
-
-	spin_lock_irqsave(&mos_parport->listlock, flags);
-	if (list_empty(&mos_parport->deferred_urbs)) {
-		spin_unlock_irqrestore(&mos_parport->listlock, flags);
-		mutex_unlock(&mos_parport->serial->disc_mutex);
-		dev_dbg(dev, "%s: deferred_urbs list empty\n", __func__);
-		return;
-	}
-
-	/* move contents of deferred_urbs list to active_urbs list and submit */
-	list_for_each_safe(cursor, next, &mos_parport->deferred_urbs)
-		list_move_tail(cursor, &mos_parport->active_urbs);
-	list_for_each_entry_safe(urbtrack, tmp, &mos_parport->active_urbs,
-			    urblist_entry) {
-		ret_val = usb_submit_urb(urbtrack->urb, GFP_ATOMIC);
-		dev_dbg(dev, "%s: urb submitted\n", __func__);
-		if (ret_val) {
-			dev_err(dev, "usb_submit_urb() failed: %d\n", ret_val);
-			list_del(&urbtrack->urblist_entry);
-			kref_put(&urbtrack->ref_count, destroy_urbtracker);
-		}
-	}
-	spin_unlock_irqrestore(&mos_parport->listlock, flags);
-	mutex_unlock(&mos_parport->serial->disc_mutex);
-}
-
-/* callback for parallel port control urbs submitted asynchronously */
-static void async_complete(struct urb *urb)
-{
-	struct urbtracker *urbtrack = urb->context;
-	int status = urb->status;
-
-	if (unlikely(status))
-		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n", __func__, status);
-
-	/* remove the urbtracker from the active_urbs list */
-	spin_lock(&urbtrack->mos_parport->listlock);
-	list_del(&urbtrack->urblist_entry);
-	spin_unlock(&urbtrack->mos_parport->listlock);
-	kref_put(&urbtrack->ref_count, destroy_urbtracker);
-}
-
-static int write_parport_reg_nonblock(struct mos7715_parport *mos_parport,
-				      enum mos_regs reg, __u8 data)
-{
-	struct urbtracker *urbtrack;
-	int ret_val;
-	unsigned long flags;
-	struct usb_serial *serial = mos_parport->serial;
-	struct usb_device *usbdev = serial->dev;
-
-	/* create and initialize the control urb and containing urbtracker */
-	urbtrack = kmalloc(sizeof(struct urbtracker), GFP_ATOMIC);
-	if (!urbtrack)
-		return -ENOMEM;
-
-	kref_get(&mos_parport->ref_count);
-	urbtrack->mos_parport = mos_parport;
-	urbtrack->urb = usb_alloc_urb(0, GFP_ATOMIC);
-	if (!urbtrack->urb) {
-		kfree(urbtrack);
-		return -ENOMEM;
-	}
-	urbtrack->setup = kmalloc(sizeof(*urbtrack->setup), GFP_ATOMIC);
-	if (!urbtrack->setup) {
-		usb_free_urb(urbtrack->urb);
-		kfree(urbtrack);
-		return -ENOMEM;
-	}
-	urbtrack->setup->bRequestType = (__u8)0x40;
-	urbtrack->setup->bRequest = (__u8)0x0e;
-	urbtrack->setup->wValue = cpu_to_le16(get_reg_value(reg, dummy));
-	urbtrack->setup->wIndex = cpu_to_le16(get_reg_index(reg));
-	urbtrack->setup->wLength = 0;
-	usb_fill_control_urb(urbtrack->urb, usbdev,
-			     usb_sndctrlpipe(usbdev, 0),
-			     (unsigned char *)urbtrack->setup,
-			     NULL, 0, async_complete, urbtrack);
-	kref_init(&urbtrack->ref_count);
-	INIT_LIST_HEAD(&urbtrack->urblist_entry);
-
-	/*
-	 * get the disconnect mutex, or add tracker to the deferred_urbs list
-	 * and schedule a tasklet to try again later
-	 */
-	if (!mutex_trylock(&serial->disc_mutex)) {
-		spin_lock_irqsave(&mos_parport->listlock, flags);
-		list_add_tail(&urbtrack->urblist_entry,
-			      &mos_parport->deferred_urbs);
-		spin_unlock_irqrestore(&mos_parport->listlock, flags);
-		tasklet_schedule(&mos_parport->urb_tasklet);
-		dev_dbg(&usbdev->dev, "tasklet scheduled\n");
-		return 0;
-	}
-
-	/* bail if device disconnected */
-	if (serial->disconnected) {
-		kref_put(&urbtrack->ref_count, destroy_urbtracker);
-		mutex_unlock(&serial->disc_mutex);
-		return -ENODEV;
-	}
-
-	/* add the tracker to the active_urbs list and submit */
-	spin_lock_irqsave(&mos_parport->listlock, flags);
-	list_add_tail(&urbtrack->urblist_entry, &mos_parport->active_urbs);
-	spin_unlock_irqrestore(&mos_parport->listlock, flags);
-	ret_val = usb_submit_urb(urbtrack->urb, GFP_ATOMIC);
-	mutex_unlock(&serial->disc_mutex);
-	if (ret_val) {
-		dev_err(&usbdev->dev,
-			"%s: submit_urb() failed: %d\n", __func__, ret_val);
-		spin_lock_irqsave(&mos_parport->listlock, flags);
-		list_del(&urbtrack->urblist_entry);
-		spin_unlock_irqrestore(&mos_parport->listlock, flags);
-		kref_put(&urbtrack->ref_count, destroy_urbtracker);
-		return ret_val;
-	}
-	return 0;
-}
-
-/*
- * This is the the common top part of all parallel port callback operations that
+ * This is the common top part of all parallel port callback operations that
  * send synchronous messages to the device.  This implements convoluted locking
  * that avoids two scenarios: (1) a port operation is called after usbserial
  * has called our release function, at which point struct mos7715_parport has
@@ -459,6 +283,10 @@ static int parport_prologue(struct parport *pp)
 	reinit_completion(&mos_parport->syncmsg_compl);
 	spin_unlock(&release_lock);
 
+	/* ensure writes from restore are submitted before new requests */
+	if (work_pending(&mos_parport->work))
+		flush_work(&mos_parport->work);
+
 	mutex_lock(&mos_parport->serial->disc_mutex);
 	if (mos_parport->serial->disconnected) {
 		/* device disconnected */
@@ -483,6 +311,26 @@ static inline void parport_epilogue(struct parport *pp)
 	complete(&mos_parport->syncmsg_compl);
 }
 
+static void deferred_restore_writes(struct work_struct *work)
+{
+	struct mos7715_parport *mos_parport;
+
+	mos_parport = container_of(work, struct mos7715_parport, work);
+
+	mutex_lock(&mos_parport->serial->disc_mutex);
+
+	/* if device disconnected, game over */
+	if (mos_parport->serial->disconnected)
+		goto done;
+
+	write_mos_reg(mos_parport->serial, dummy, MOS7720_DCR,
+		      mos_parport->shadowDCR);
+	write_mos_reg(mos_parport->serial, dummy, MOS7720_ECR,
+		      mos_parport->shadowECR);
+done:
+	mutex_unlock(&mos_parport->serial->disc_mutex);
+}
+
 static void parport_mos7715_write_data(struct parport *pp, unsigned char d)
 {
 	struct mos7715_parport *mos_parport = pp->private_data;
@@ -521,7 +369,7 @@ static void parport_mos7715_write_control(struct parport *pp, unsigned char d)
 
 static unsigned char parport_mos7715_read_control(struct parport *pp)
 {
-	struct mos7715_parport *mos_parport = pp->private_data;
+	struct mos7715_parport *mos_parport;
 	__u8 dcr;
 
 	spin_lock(&release_lock);
@@ -557,7 +405,7 @@ static unsigned char parport_mos7715_frob_control(struct parport *pp,
 static unsigned char parport_mos7715_read_status(struct parport *pp)
 {
 	unsigned char status;
-	struct mos7715_parport *mos_parport = pp->private_data;
+	struct mos7715_parport *mos_parport;
 
 	spin_lock(&release_lock);
 	mos_parport = pp->private_data;
@@ -640,10 +488,10 @@ static void parport_mos7715_restore_state(struct parport *pp,
 		spin_unlock(&release_lock);
 		return;
 	}
-	write_parport_reg_nonblock(mos_parport, MOS7720_DCR,
-				   mos_parport->shadowDCR);
-	write_parport_reg_nonblock(mos_parport, MOS7720_ECR,
-				   mos_parport->shadowECR);
+	mos_parport->shadowDCR = s->u.pc.ctr;
+	mos_parport->shadowECR = s->u.pc.ecr;
+
+	schedule_work(&mos_parport->work);
 	spin_unlock(&release_lock);
 }
 
@@ -713,13 +561,9 @@ static int mos7715_parport_init(struct usb_serial *serial)
 
 	mos_parport->msg_pending = false;
 	kref_init(&mos_parport->ref_count);
-	spin_lock_init(&mos_parport->listlock);
-	INIT_LIST_HEAD(&mos_parport->active_urbs);
-	INIT_LIST_HEAD(&mos_parport->deferred_urbs);
 	usb_set_serial_data(serial, mos_parport); /* hijack private pointer */
 	mos_parport->serial = serial;
-	tasklet_init(&mos_parport->urb_tasklet, send_deferred_urbs,
-		     (unsigned long) mos_parport);
+	INIT_WORK(&mos_parport->work, deferred_restore_writes);
 	init_completion(&mos_parport->syncmsg_compl);
 
 	/* cycle parallel port reset bit */
@@ -982,7 +826,7 @@ static int mos77xx_calc_num_ports(struct usb_serial *serial,
 		/*
 		 * The 7715 uses the first bulk in/out endpoint pair for the
 		 * parallel port, and the second for the serial port. We swap
-		 * the endpoint descriptors here so that the the first and
+		 * the endpoint descriptors here so that the first and
 		 * only registered port structure uses the serial-port
 		 * endpoints.
 		 */
@@ -1101,27 +945,20 @@ static int mos7720_open(struct tty_struct *tty, struct usb_serial_port *port)
  *	this function is called by the tty driver when it wants to know how many
  *	bytes of data we currently have outstanding in the port (data that has
  *	been written, but hasn't made it out the port yet)
- *	If successful, we return the number of bytes left to be written in the
- *	system,
- *	Otherwise we return a negative error number.
  */
-static int mos7720_chars_in_buffer(struct tty_struct *tty)
+static unsigned int mos7720_chars_in_buffer(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
+	struct moschip_port *mos7720_port = usb_get_serial_port_data(port);
 	int i;
-	int chars = 0;
-	struct moschip_port *mos7720_port;
-
-	mos7720_port = usb_get_serial_port_data(port);
-	if (mos7720_port == NULL)
-		return 0;
+	unsigned int chars = 0;
 
 	for (i = 0; i < NUM_URBS; ++i) {
 		if (mos7720_port->write_urb_pool[i] &&
 		    mos7720_port->write_urb_pool[i]->status == -EINPROGRESS)
 			chars += URB_TRANSFER_BUFFER_SIZE;
 	}
-	dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
+	dev_dbg(&port->dev, "%s - returns %u\n", __func__, chars);
 	return chars;
 }
 
@@ -1159,7 +996,7 @@ static void mos7720_close(struct usb_serial_port *port)
 	mos7720_port->open = 0;
 }
 
-static void mos7720_break(struct tty_struct *tty, int break_state)
+static int mos7720_break(struct tty_struct *tty, int break_state)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	unsigned char data;
@@ -1170,7 +1007,7 @@ static void mos7720_break(struct tty_struct *tty, int break_state)
 
 	mos7720_port = usb_get_serial_port_data(port);
 	if (mos7720_port == NULL)
-		return;
+		return -ENODEV;
 
 	if (break_state == -1)
 		data = mos7720_port->shadowLCR | UART_LCR_SBC;
@@ -1178,28 +1015,23 @@ static void mos7720_break(struct tty_struct *tty, int break_state)
 		data = mos7720_port->shadowLCR & ~UART_LCR_SBC;
 
 	mos7720_port->shadowLCR  = data;
-	write_mos_reg(serial, port->port_number, MOS7720_LCR,
-		      mos7720_port->shadowLCR);
+
+	return write_mos_reg(serial, port->port_number, MOS7720_LCR,
+			     mos7720_port->shadowLCR);
 }
 
 /*
  * mos7720_write_room
  *	this function is called by the tty driver when it wants to know how many
  *	bytes of data we can accept for a specific port.
- *	If successful, we return the amount of room that we have for this port
- *	Otherwise we return a negative error number.
  */
-static int mos7720_write_room(struct tty_struct *tty)
+static unsigned int mos7720_write_room(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
-	struct moschip_port *mos7720_port;
-	int room = 0;
+	struct moschip_port *mos7720_port = usb_get_serial_port_data(port);
+	unsigned int room = 0;
 	int i;
 
-	mos7720_port = usb_get_serial_port_data(port);
-	if (mos7720_port == NULL)
-		return -ENODEV;
-
 	/* FIXME: Locking */
 	for (i = 0; i < NUM_URBS; ++i) {
 		if (mos7720_port->write_urb_pool[i] &&
@@ -1207,7 +1039,7 @@ static int mos7720_write_room(struct tty_struct *tty)
 			room += URB_TRANSFER_BUFFER_SIZE;
 	}
 
-	dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
+	dev_dbg(&port->dev, "%s - returns %u\n", __func__, room);
 	return room;
 }
 
@@ -1250,8 +1082,10 @@ static int mos7720_write(struct tty_struct *tty, struct usb_serial_port *port,
 	if (urb->transfer_buffer == NULL) {
 		urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
 					       GFP_ATOMIC);
-		if (!urb->transfer_buffer)
+		if (!urb->transfer_buffer) {
+			bytes_sent = -ENOMEM;
 			goto exit;
+		}
 	}
 	transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
 
@@ -1523,14 +1357,12 @@ static int send_cmd_write_baud_rate(struct moschip_port *mos7720_port,
  */
 static void change_port_settings(struct tty_struct *tty,
 				 struct moschip_port *mos7720_port,
-				 struct ktermios *old_termios)
+				 const struct ktermios *old_termios)
 {
 	struct usb_serial_port *port;
 	struct usb_serial *serial;
 	int baud;
 	unsigned cflag;
-	unsigned iflag;
-	__u8 mask = 0xff;
 	__u8 lData;
 	__u8 lParity;
 	__u8 lStop;
@@ -1549,34 +1381,12 @@ static void change_port_settings(struct tty_struct *tty,
 		return;
 	}
 
-	lData = UART_LCR_WLEN8;
 	lStop = 0x00;	/* 1 stop bit */
 	lParity = 0x00;	/* No parity */
 
 	cflag = tty->termios.c_cflag;
-	iflag = tty->termios.c_iflag;
 
-	/* Change the number of bits */
-	switch (cflag & CSIZE) {
-	case CS5:
-		lData = UART_LCR_WLEN5;
-		mask = 0x1f;
-		break;
-
-	case CS6:
-		lData = UART_LCR_WLEN6;
-		mask = 0x3f;
-		break;
-
-	case CS7:
-		lData = UART_LCR_WLEN7;
-		mask = 0x7f;
-		break;
-	default:
-	case CS8:
-		lData = UART_LCR_WLEN8;
-		break;
-	}
+	lData = UART_LCR_WLEN(tty_get_char_size(cflag));
 
 	/* Change the Parity bit */
 	if (cflag & PARENB) {
@@ -1685,14 +1495,12 @@ static void change_port_settings(struct tty_struct *tty,
  *	termios structure.
  */
 static void mos7720_set_termios(struct tty_struct *tty,
-		struct usb_serial_port *port, struct ktermios *old_termios)
+				struct usb_serial_port *port,
+				const struct ktermios *old_termios)
 {
 	int status;
-	struct usb_serial *serial;
 	struct moschip_port *mos7720_port;
 
-	serial = port->serial;
-
 	mos7720_port = usb_get_serial_port_data(port);
 
 	if (mos7720_port == NULL)
@@ -1797,72 +1605,6 @@ static int mos7720_tiocmset(struct tty_struct *tty,
 	return 0;
 }
 
-static int set_modem_info(struct moschip_port *mos7720_port, unsigned int cmd,
-			  unsigned int __user *value)
-{
-	unsigned int mcr;
-	unsigned int arg;
-
-	struct usb_serial_port *port;
-
-	if (mos7720_port == NULL)
-		return -1;
-
-	port = (struct usb_serial_port *)mos7720_port->port;
-	mcr = mos7720_port->shadowMCR;
-
-	if (copy_from_user(&arg, value, sizeof(int)))
-		return -EFAULT;
-
-	switch (cmd) {
-	case TIOCMBIS:
-		if (arg & TIOCM_RTS)
-			mcr |= UART_MCR_RTS;
-		if (arg & TIOCM_DTR)
-			mcr |= UART_MCR_RTS;
-		if (arg & TIOCM_LOOP)
-			mcr |= UART_MCR_LOOP;
-		break;
-
-	case TIOCMBIC:
-		if (arg & TIOCM_RTS)
-			mcr &= ~UART_MCR_RTS;
-		if (arg & TIOCM_DTR)
-			mcr &= ~UART_MCR_RTS;
-		if (arg & TIOCM_LOOP)
-			mcr &= ~UART_MCR_LOOP;
-		break;
-
-	}
-
-	mos7720_port->shadowMCR = mcr;
-	write_mos_reg(port->serial, port->port_number, MOS7720_MCR,
-		      mos7720_port->shadowMCR);
-
-	return 0;
-}
-
-static int get_serial_info(struct moschip_port *mos7720_port,
-			   struct serial_struct __user *retinfo)
-{
-	struct serial_struct tmp;
-
-	memset(&tmp, 0, sizeof(tmp));
-
-	tmp.type		= PORT_16550A;
-	tmp.line		= mos7720_port->port->minor;
-	tmp.port		= mos7720_port->port->port_number;
-	tmp.irq			= 0;
-	tmp.xmit_fifo_size	= NUM_URBS * URB_TRANSFER_BUFFER_SIZE;
-	tmp.baud_base		= 9600;
-	tmp.close_delay		= 5*HZ;
-	tmp.closing_wait	= 30*HZ;
-
-	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
-		return -EFAULT;
-	return 0;
-}
-
 static int mos7720_ioctl(struct tty_struct *tty,
 			 unsigned int cmd, unsigned long arg)
 {
@@ -1878,18 +1620,6 @@ static int mos7720_ioctl(struct tty_struct *tty,
 		dev_dbg(&port->dev, "%s TIOCSERGETLSR\n", __func__);
 		return get_lsr_info(tty, mos7720_port,
 					(unsigned int __user *)arg);
-
-	/* FIXME: These should be using the mode methods */
-	case TIOCMBIS:
-	case TIOCMBIC:
-		dev_dbg(&port->dev, "%s TIOCMSET/TIOCMBIC/TIOCMSET\n", __func__);
-		return set_modem_info(mos7720_port, cmd,
-				      (unsigned int __user *)arg);
-
-	case TIOCGSERIAL:
-		dev_dbg(&port->dev, "%s TIOCGSERIAL\n", __func__);
-		return get_serial_info(mos7720_port,
-				       (struct serial_struct __user *)arg);
 	}
 
 	return -ENOIOCTLCMD;
@@ -1905,10 +1635,6 @@ static int mos7720_startup(struct usb_serial *serial)
 	product = le16_to_cpu(serial->dev->descriptor.idProduct);
 	dev = serial->dev;
 
-	/* setting configuration feature to one */
-	usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
-			(__u8)0x03, 0x00, 0x01, 0x00, NULL, 0x00, 5000);
-
 	if (product == MOSCHIP_DEVICE_ID_7715) {
 		struct urb *urb = serial->port[0]->interrupt_in_urb;
 
@@ -1943,8 +1669,6 @@ static void mos7720_release(struct usb_serial *serial)
 
 	if (le16_to_cpu(serial->dev->descriptor.idProduct)
 	    == MOSCHIP_DEVICE_ID_7715) {
-		struct urbtracker *urbtrack;
-		unsigned long flags;
 		struct mos7715_parport *mos_parport =
 			usb_get_serial_data(serial);
 
@@ -1957,21 +1681,17 @@ static void mos7720_release(struct usb_serial *serial)
 		if (mos_parport->msg_pending)
 			wait_for_completion_timeout(&mos_parport->syncmsg_compl,
 					    msecs_to_jiffies(MOS_WDR_TIMEOUT));
+		/*
+		 * If delayed work is currently scheduled, wait for it to
+		 * complete. This also implies barriers that ensure the
+		 * below serial clearing is not hoisted above the ->work.
+		 */
+		cancel_work_sync(&mos_parport->work);
 
 		parport_remove_port(mos_parport->pp);
 		usb_set_serial_data(serial, NULL);
 		mos_parport->serial = NULL;
 
-		/* if tasklet currently scheduled, wait for it to complete */
-		tasklet_kill(&mos_parport->urb_tasklet);
-
-		/* unlink any urbs sent by the tasklet  */
-		spin_lock_irqsave(&mos_parport->listlock, flags);
-		list_for_each_entry(urbtrack,
-				    &mos_parport->active_urbs,
-				    urblist_entry)
-			usb_unlink_urb(urbtrack->urb);
-		spin_unlock_irqrestore(&mos_parport->listlock, flags);
 		parport_del_port(mos_parport->pp);
 
 		kref_put(&mos_parport->ref_count, destroy_mos_parport);
@@ -1994,19 +1714,16 @@ static int mos7720_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int mos7720_port_remove(struct usb_serial_port *port)
+static void mos7720_port_remove(struct usb_serial_port *port)
 {
 	struct moschip_port *mos7720_port;
 
 	mos7720_port = usb_get_serial_port_data(port);
 	kfree(mos7720_port);
-
-	return 0;
 }
 
 static struct usb_serial_driver moschip7720_2port_driver = {
 	.driver = {
-		.owner =	THIS_MODULE,
 		.name =		"moschip7720",
 	},
 	.description		= "Moschip 2 port adapter",
@@ -2043,4 +1760,4 @@ module_usb_serial_driver(serial_drivers, id_table);
 
 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");