USB: use "device number" instead of "address"

The USB stack historically has conflated device numbers (i.e., the
value of udev->devnum) with device addresses.  This is understandable,
because until recently the two values were always the same.

But with USB-3.0 they aren't the same, so we should start calling
these things by their correct names.  This patch (as1449b) changes many
of the references to "address" in the hub driver to "device number"
or "devnum".

The patch also removes some unnecessary or misleading comments.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Luben Tuikov <ltuikov@yahoo.com>
Reviewed-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

@@ -1499,6 +1499,13 @@ void usb_set_device_state(struct usb_device *udev,
 EXPORT_SYMBOL_GPL(usb_set_device_state);
 
 /*
+ * Choose a device number.
+ *
+ * Device numbers are used as filenames in usbfs.  On USB-1.1 and
+ * USB-2.0 buses they are also used as device addresses, however on
+ * USB-3.0 buses the address is assigned by the controller hardware
+ * and it usually is not the same as the device number.
+ *
  * WUSB devices are simple: they have no hubs behind, so the mapping
  * device <-> virtual port number becomes 1:1. Why? to simplify the
  * life of the device connection logic in
@@ -1520,7 +1527,7 @@ EXPORT_SYMBOL_GPL(usb_set_device_state);
  * the HCD must setup data structures before issuing a set address
  * command to the hardware.
  */
-static void choose_address(struct usb_device *udev)
+static void choose_devnum(struct usb_device *udev)
 {
 	int		devnum;
 	struct usb_bus	*bus = udev->bus;
@@ -1545,7 +1552,7 @@ static void choose_address(struct usb_device *udev)
 	}
 }
 
-static void release_address(struct usb_device *udev)
+static void release_devnum(struct usb_device *udev)
 {
 	if (udev->devnum > 0) {
 		clear_bit(udev->devnum, udev->bus->devmap.devicemap);
@@ -1553,7 +1560,7 @@ static void release_address(struct usb_device *udev)
 	}
 }
 
-static void update_address(struct usb_device *udev, int devnum)
+static void update_devnum(struct usb_device *udev, int devnum)
 {
 	/* The address for a WUSB device is managed by wusbcore. */
 	if (!udev->wusb)
@@ -1600,7 +1607,8 @@ void usb_disconnect(struct usb_device **pdev)
 	 * this quiesces everyting except pending urbs.
 	 */
 	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
-	dev_info (&udev->dev, "USB disconnect, address %d\n", udev->devnum);
+	dev_info(&udev->dev, "USB disconnect, device number %d\n",
+			udev->devnum);
 
 	usb_lock_device(udev);
 
@@ -1630,7 +1638,7 @@ void usb_disconnect(struct usb_device **pdev)
 	/* Free the device number and delete the parent's children[]
 	 * (or root_hub) pointer.
 	 */
-	release_address(udev);
+	release_devnum(udev);
 
 	/* Avoid races with recursively_mark_NOTATTACHED() */
 	spin_lock_irq(&device_state_lock);
@@ -2071,7 +2079,7 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
 		case 0:
 			/* TRSTRCY = 10 ms; plus some extra */
 			msleep(10 + 40);
-			update_address(udev, 0);
+			update_devnum(udev, 0);
 			if (hcd->driver->reset_device) {
 				status = hcd->driver->reset_device(hcd, udev);
 				if (status < 0) {
@@ -2634,7 +2642,7 @@ static int hub_set_address(struct usb_device *udev, int devnum)
 				USB_REQ_SET_ADDRESS, 0, devnum, 0,
 				NULL, 0, USB_CTRL_SET_TIMEOUT);
 	if (retval == 0) {
-		update_address(udev, devnum);
+		update_devnum(udev, devnum);
 		/* Device now using proper address. */
 		usb_set_device_state(udev, USB_STATE_ADDRESS);
 		usb_ep0_reinit(udev);
@@ -2743,9 +2751,9 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 	}
 	if (udev->speed != USB_SPEED_SUPER)
 		dev_info(&udev->dev,
-				"%s %s speed %sUSB device using %s and address %d\n",
+				"%s %s speed %sUSB device number %d using %s\n",
 				(udev->config) ? "reset" : "new", speed, type,
-				udev->bus->controller->driver->name, devnum);
+				devnum, udev->bus->controller->driver->name);
 
 	/* Set up TT records, if needed  */
 	if (hdev->tt) {
@@ -2775,10 +2783,6 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 	 * value.
 	 */
 	for (i = 0; i < GET_DESCRIPTOR_TRIES; (++i, msleep(100))) {
-		/*
-		 * An xHCI controller cannot send any packets to a device until
-		 * a set address command successfully completes.
-		 */
 		if (USE_NEW_SCHEME(retry_counter) && !(hcd->driver->flags & HCD_USB3)) {
 			struct usb_device_descriptor *buf;
 			int r = 0;
@@ -2861,9 +2865,9 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 			if (udev->speed == USB_SPEED_SUPER) {
 				devnum = udev->devnum;
 				dev_info(&udev->dev,
-						"%s SuperSpeed USB device using %s and address %d\n",
+						"%s SuperSpeed USB device number %d using %s\n",
 						(udev->config) ? "reset" : "new",
-						udev->bus->controller->driver->name, devnum);
+						devnum, udev->bus->controller->driver->name);
 			}
 
 			/* cope with hardware quirkiness:
@@ -2926,7 +2930,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 fail:
 	if (retval) {
 		hub_port_disable(hub, port1, 0);
-		update_address(udev, devnum);	/* for disconnect processing */
+		update_devnum(udev, devnum);	/* for disconnect processing */
 	}
 	mutex_unlock(&usb_address0_mutex);
 	return retval;
@@ -3135,15 +3139,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 		else
 			udev->speed = USB_SPEED_UNKNOWN;
 
-		/*
-		 * Set the address.
-		 * Note xHCI needs to issue an address device command later
-		 * in the hub_port_init sequence for SS/HS/FS/LS devices,
-		 * and xHC will assign an address to the device. But use
-		 * kernel assigned address here, to avoid any address conflict
-		 * issue.
-		 */
-		choose_address(udev);
+		choose_devnum(udev);
 		if (udev->devnum <= 0) {
 			status = -ENOTCONN;	/* Don't retry */
 			goto loop;
@@ -3235,7 +3231,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 		hub_port_disable(hub, port1, 1);
 loop:
 		usb_ep0_reinit(udev);
-		release_address(udev);
+		release_devnum(udev);
 		hub_free_dev(udev);
 		usb_put_dev(udev);
 		if ((status == -ENOTCONN) || (status == -ENOTSUPP))