USB: mos7840: fix port-data memory leak

Fix port-data memory leak by moving port data allocation and
deallocation to port_probe and port_remove.

Since commit 0998d063 (device-core: Ensure drvdata = NULL when no
driver is bound) the port private data is no longer freed at release as
it is no longer accessible.

Note that the indentation was kept intact using a do-while(0) in order
to facilitate review. A follow-up patch will remove it.

Compile-only tested.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/mos7840.c

@@ -2327,49 +2327,45 @@ static int mos7840_calc_num_ports(struct usb_serial *serial)
 	return mos7840_num_ports;
 }
 
-/****************************************************************************
- * mos7840_startup
- ****************************************************************************/
-
-static int mos7840_startup(struct usb_serial *serial)
+static int mos7840_port_probe(struct usb_serial_port *port)
 {
+	struct usb_serial *serial = port->serial;
 	struct moschip_port *mos7840_port;
-	struct usb_device *dev;
-	int i, status;
+	int status;
+	int pnum;
 	__u16 Data;
 
-	dev = serial->dev;
-
 	/* we set up the pointers to the endpoints in the mos7840_open *
 	 * function, as the structures aren't created yet.             */
 
-	/* set up port private structures */
-	for (i = 0; i < serial->num_ports; ++i) {
-		dev_dbg(&dev->dev, "mos7840_startup: configuring port %d............\n", i);
+	pnum = port->number - serial->minor;
+
+	/* FIXME: remove do-while(0) loop used to keep stable patch minimal.
+	 */
+	do {
+		dev_dbg(&port->dev, "mos7840_startup: configuring port %d............\n", pnum);
 		mos7840_port = kzalloc(sizeof(struct moschip_port), GFP_KERNEL);
 		if (mos7840_port == NULL) {
-			dev_err(&dev->dev, "%s - Out of memory\n", __func__);
-			status = -ENOMEM;
-			i--; /* don't follow NULL pointer cleaning up */
-			goto error;
+			dev_err(&port->dev, "%s - Out of memory\n", __func__);
+			return -ENOMEM;
 		}
 
 		/* Initialize all port interrupt end point to port 0 int
 		 * endpoint. Our device has only one interrupt end point
 		 * common to all port */
 
-		mos7840_port->port = serial->port[i];
-		mos7840_set_port_private(serial->port[i], mos7840_port);
+		mos7840_port->port = port;
+		mos7840_set_port_private(port, mos7840_port);
 		spin_lock_init(&mos7840_port->pool_lock);
 
 		/* minor is not initialised until later by
 		 * usb-serial.c:get_free_serial() and cannot therefore be used
 		 * to index device instances */
-		mos7840_port->port_num = i + 1;
-		dev_dbg(&dev->dev, "serial->port[i]->number = %d\n", serial->port[i]->number);
-		dev_dbg(&dev->dev, "serial->port[i]->serial->minor = %d\n", serial->port[i]->serial->minor);
-		dev_dbg(&dev->dev, "mos7840_port->port_num = %d\n", mos7840_port->port_num);
-		dev_dbg(&dev->dev, "serial->minor = %d\n", serial->minor);
+		mos7840_port->port_num = pnum + 1;
+		dev_dbg(&port->dev, "port->number = %d\n", port->number);
+		dev_dbg(&port->dev, "port->serial->minor = %d\n", port->serial->minor);
+		dev_dbg(&port->dev, "mos7840_port->port_num = %d\n", mos7840_port->port_num);
+		dev_dbg(&port->dev, "serial->minor = %d\n", serial->minor);
 
 		if (mos7840_port->port_num == 1) {
 			mos7840_port->SpRegOffset = 0x0;
@@ -2396,115 +2392,115 @@ static int mos7840_startup(struct usb_serial *serial)
 			mos7840_port->ControlRegOffset = 0xd;
 			mos7840_port->DcrRegOffset = 0x1c;
 		}
-		mos7840_dump_serial_port(serial->port[i], mos7840_port);
-		mos7840_set_port_private(serial->port[i], mos7840_port);
+		mos7840_dump_serial_port(port, mos7840_port);
+		mos7840_set_port_private(port, mos7840_port);
 
 		/* enable rx_disable bit in control register */
-		status = mos7840_get_reg_sync(serial->port[i],
+		status = mos7840_get_reg_sync(port,
 				 mos7840_port->ControlRegOffset, &Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Reading ControlReg failed status-0x%x\n", status);
+			dev_dbg(&port->dev, "Reading ControlReg failed status-0x%x\n", status);
 			break;
 		} else
-			dev_dbg(&dev->dev, "ControlReg Reading success val is %x, status%d\n", Data, status);
+			dev_dbg(&port->dev, "ControlReg Reading success val is %x, status%d\n", Data, status);
 		Data |= 0x08;	/* setting driver done bit */
 		Data |= 0x04;	/* sp1_bit to have cts change reflect in
 				   modem status reg */
 
 		/* Data |= 0x20; //rx_disable bit */
-		status = mos7840_set_reg_sync(serial->port[i],
+		status = mos7840_set_reg_sync(port,
 					 mos7840_port->ControlRegOffset, Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Writing ControlReg failed(rx_disable) status-0x%x\n", status);
+			dev_dbg(&port->dev, "Writing ControlReg failed(rx_disable) status-0x%x\n", status);
 			break;
 		} else
-			dev_dbg(&dev->dev, "ControlReg Writing success(rx_disable) status%d\n", status);
+			dev_dbg(&port->dev, "ControlReg Writing success(rx_disable) status%d\n", status);
 
 		/* Write default values in DCR (i.e 0x01 in DCR0, 0x05 in DCR2
 		   and 0x24 in DCR3 */
 		Data = 0x01;
-		status = mos7840_set_reg_sync(serial->port[i],
+		status = mos7840_set_reg_sync(port,
 			 (__u16) (mos7840_port->DcrRegOffset + 0), Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Writing DCR0 failed status-0x%x\n", status);
+			dev_dbg(&port->dev, "Writing DCR0 failed status-0x%x\n", status);
 			break;
 		} else
-			dev_dbg(&dev->dev, "DCR0 Writing success status%d\n", status);
+			dev_dbg(&port->dev, "DCR0 Writing success status%d\n", status);
 
 		Data = 0x05;
-		status = mos7840_set_reg_sync(serial->port[i],
+		status = mos7840_set_reg_sync(port,
 			 (__u16) (mos7840_port->DcrRegOffset + 1), Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Writing DCR1 failed status-0x%x\n", status);
+			dev_dbg(&port->dev, "Writing DCR1 failed status-0x%x\n", status);
 			break;
 		} else
-			dev_dbg(&dev->dev, "DCR1 Writing success status%d\n", status);
+			dev_dbg(&port->dev, "DCR1 Writing success status%d\n", status);
 
 		Data = 0x24;
-		status = mos7840_set_reg_sync(serial->port[i],
+		status = mos7840_set_reg_sync(port,
 			 (__u16) (mos7840_port->DcrRegOffset + 2), Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Writing DCR2 failed status-0x%x\n", status);
+			dev_dbg(&port->dev, "Writing DCR2 failed status-0x%x\n", status);
 			break;
 		} else
-			dev_dbg(&dev->dev, "DCR2 Writing success status%d\n", status);
+			dev_dbg(&port->dev, "DCR2 Writing success status%d\n", status);
 
 		/* write values in clkstart0x0 and clkmulti 0x20 */
 		Data = 0x0;
-		status = mos7840_set_reg_sync(serial->port[i],
+		status = mos7840_set_reg_sync(port,
 					 CLK_START_VALUE_REGISTER, Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Writing CLK_START_VALUE_REGISTER failed status-0x%x\n", status);
+			dev_dbg(&port->dev, "Writing CLK_START_VALUE_REGISTER failed status-0x%x\n", status);
 			break;
 		} else
-			dev_dbg(&dev->dev, "CLK_START_VALUE_REGISTER Writing success status%d\n", status);
+			dev_dbg(&port->dev, "CLK_START_VALUE_REGISTER Writing success status%d\n", status);
 
 		Data = 0x20;
-		status = mos7840_set_reg_sync(serial->port[i],
+		status = mos7840_set_reg_sync(port,
 					CLK_MULTI_REGISTER, Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Writing CLK_MULTI_REGISTER failed status-0x%x\n", status);
+			dev_dbg(&port->dev, "Writing CLK_MULTI_REGISTER failed status-0x%x\n", status);
 			goto error;
 		} else
-			dev_dbg(&dev->dev, "CLK_MULTI_REGISTER Writing success status%d\n", status);
+			dev_dbg(&port->dev, "CLK_MULTI_REGISTER Writing success status%d\n", status);
 
 		/* write value 0x0 to scratchpad register */
 		Data = 0x00;
-		status = mos7840_set_uart_reg(serial->port[i],
+		status = mos7840_set_uart_reg(port,
 						SCRATCH_PAD_REGISTER, Data);
 		if (status < 0) {
-			dev_dbg(&dev->dev, "Writing SCRATCH_PAD_REGISTER failed status-0x%x\n", status);
+			dev_dbg(&port->dev, "Writing SCRATCH_PAD_REGISTER failed status-0x%x\n", status);
 			break;
 		} else
-			dev_dbg(&dev->dev, "SCRATCH_PAD_REGISTER Writing success status%d\n", status);
+			dev_dbg(&port->dev, "SCRATCH_PAD_REGISTER Writing success status%d\n", status);
 
 		/* Zero Length flag register */
 		if ((mos7840_port->port_num != 1)
 		    && (serial->num_ports == 2)) {
 
 			Data = 0xff;
-			status = mos7840_set_reg_sync(serial->port[i],
+			status = mos7840_set_reg_sync(port,
 				      (__u16) (ZLP_REG1 +
 				      ((__u16)mos7840_port->port_num)), Data);
-			dev_dbg(&dev->dev, "ZLIP offset %x\n",
+			dev_dbg(&port->dev, "ZLIP offset %x\n",
 				(__u16)(ZLP_REG1 + ((__u16) mos7840_port->port_num)));
 			if (status < 0) {
-				dev_dbg(&dev->dev, "Writing ZLP_REG%d failed status-0x%x\n", i + 2, status);
+				dev_dbg(&port->dev, "Writing ZLP_REG%d failed status-0x%x\n", pnum + 2, status);
 				break;
 			} else
-				dev_dbg(&dev->dev, "ZLP_REG%d Writing success status%d\n", i + 2, status);
+				dev_dbg(&port->dev, "ZLP_REG%d Writing success status%d\n", pnum + 2, status);
 		} else {
 			Data = 0xff;
-			status = mos7840_set_reg_sync(serial->port[i],
+			status = mos7840_set_reg_sync(port,
 			      (__u16) (ZLP_REG1 +
 			      ((__u16)mos7840_port->port_num) - 0x1), Data);
-			dev_dbg(&dev->dev, "ZLIP offset %x\n",
+			dev_dbg(&port->dev, "ZLIP offset %x\n",
 				(__u16)(ZLP_REG1 + ((__u16) mos7840_port->port_num) - 0x1));
 			if (status < 0) {
-				dev_dbg(&dev->dev, "Writing ZLP_REG%d failed status-0x%x\n", i + 1, status);
+				dev_dbg(&port->dev, "Writing ZLP_REG%d failed status-0x%x\n", pnum + 1, status);
 				break;
 			} else
-				dev_dbg(&dev->dev, "ZLP_REG%d Writing success status%d\n", i + 1, status);
+				dev_dbg(&port->dev, "ZLP_REG%d Writing success status%d\n", pnum + 1, status);
 
 		}
 		mos7840_port->control_urb = usb_alloc_urb(0, GFP_KERNEL);
@@ -2541,92 +2537,56 @@ static int mos7840_startup(struct usb_serial *serial)
 			mos7840_port->led_flag = false;
 
 			/* Turn off LED */
-			mos7840_set_led_sync(serial->port[i],
+			mos7840_set_led_sync(port,
 						MODEM_CONTROL_REGISTER, 0x0300);
 		}
-	}
+	} while (0);
 
-	/* Zero Length flag enable */
-	Data = 0x0f;
-	status = mos7840_set_reg_sync(serial->port[0], ZLP_REG5, Data);
-	if (status < 0) {
-		dev_dbg(&dev->dev, "Writing ZLP_REG5 failed status-0x%x\n", status);
-		goto error;
-	} else
-		dev_dbg(&dev->dev, "ZLP_REG5 Writing success status%d\n", status);
-
-	/* setting configuration feature to one */
-	usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
-			(__u8) 0x03, 0x00, 0x01, 0x00, NULL, 0x00, MOS_WDR_TIMEOUT);
+	if (pnum == serial->num_ports - 1) {
+		/* Zero Length flag enable */
+		Data = 0x0f;
+		status = mos7840_set_reg_sync(serial->port[0], ZLP_REG5, Data);
+		if (status < 0) {
+			dev_dbg(&port->dev, "Writing ZLP_REG5 failed status-0x%x\n", status);
+			goto error;
+		} else
+			dev_dbg(&port->dev, "ZLP_REG5 Writing success status%d\n", status);
+
+		/* setting configuration feature to one */
+		usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+				0x03, 0x00, 0x01, 0x00, NULL, 0x00,
+				MOS_WDR_TIMEOUT);
+	}
 	return 0;
 error:
-	for (/* nothing */; i >= 0; i--) {
-		mos7840_port = mos7840_get_port_private(serial->port[i]);
+	kfree(mos7840_port->dr);
+	kfree(mos7840_port->ctrl_buf);
+	usb_free_urb(mos7840_port->control_urb);
+	kfree(mos7840_port);
 
-		kfree(mos7840_port->dr);
-		kfree(mos7840_port->ctrl_buf);
-		usb_free_urb(mos7840_port->control_urb);
-		kfree(mos7840_port);
-	}
 	return status;
 }
 
-/****************************************************************************
- * mos7840_disconnect
- *	This function is called whenever the device is removed from the usb bus.
- ****************************************************************************/
-
-static void mos7840_disconnect(struct usb_serial *serial)
+static int mos7840_port_remove(struct usb_serial_port *port)
 {
-	int i;
-	unsigned long flags;
 	struct moschip_port *mos7840_port;
 
-	/* check for the ports to be closed,close the ports and disconnect */
+	mos7840_port = mos7840_get_port_private(port);
 
-	/* free private structure allocated for serial port  *
-	 * stop reads and writes on all ports                */
+	if (mos7840_port->has_led) {
+		/* Turn off LED */
+		mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0300);
 
-	for (i = 0; i < serial->num_ports; ++i) {
-		mos7840_port = mos7840_get_port_private(serial->port[i]);
-		if (mos7840_port) {
-			usb_kill_urb(mos7840_port->control_urb);
-		}
+		del_timer_sync(&mos7840_port->led_timer1);
+		del_timer_sync(&mos7840_port->led_timer2);
 	}
-}
-
-/****************************************************************************
- * mos7840_release
- *	This function is called when the usb_serial structure is freed.
- ****************************************************************************/
-
-static void mos7840_release(struct usb_serial *serial)
-{
-	int i;
-	struct moschip_port *mos7840_port;
+	usb_kill_urb(mos7840_port->control_urb);
+	usb_free_urb(mos7840_port->control_urb);
+	kfree(mos7840_port->ctrl_buf);
+	kfree(mos7840_port->dr);
+	kfree(mos7840_port);
 
-	/* check for the ports to be closed,close the ports and disconnect */
-
-	/* free private structure allocated for serial port  *
-	 * stop reads and writes on all ports                */
-
-	for (i = 0; i < serial->num_ports; ++i) {
-		mos7840_port = mos7840_get_port_private(serial->port[i]);
-		if (mos7840_port) {
-			if (mos7840_port->has_led) {
-				/* Turn off LED */
-				mos7840_set_led_sync(mos7840_port->port,
-						MODEM_CONTROL_REGISTER, 0x0300);
-
-				del_timer_sync(&mos7840_port->led_timer1);
-				del_timer_sync(&mos7840_port->led_timer2);
-			}
-			usb_free_urb(mos7840_port->control_urb);
-			kfree(mos7840_port->ctrl_buf);
-			kfree(mos7840_port->dr);
-			kfree(mos7840_port);
-		}
-	}
+	return 0;
 }
 
 static struct usb_serial_driver moschip7840_4port_device = {
@@ -2654,9 +2614,8 @@ static struct usb_serial_driver moschip7840_4port_device = {
 	.tiocmget = mos7840_tiocmget,
 	.tiocmset = mos7840_tiocmset,
 	.get_icount = mos7840_get_icount,
-	.attach = mos7840_startup,
-	.disconnect = mos7840_disconnect,
-	.release = mos7840_release,
+	.port_probe = mos7840_port_probe,
+	.port_remove = mos7840_port_remove,
 	.read_bulk_callback = mos7840_bulk_in_callback,
 	.read_int_callback = mos7840_interrupt_callback,
 };