usbcore: trim down usb_bus structure

As part of the ongoing program to flatten out the HCD bus-glue layer,
this patch (as771b) eliminates the hcpriv, release, and kref fields
from struct usb_bus.  hcpriv and release were not being used for
anything worthwhile, and kref has been moved into the enclosing
usb_hcd structure.

Along with those changes, the patch gets rid of usb_bus_get and
usb_bus_put, replacing them with usb_get_hcd and usb_put_hcd.

The one interesting aspect is that the dev_set_drvdata call was
removed from usb_put_hcd, where it clearly doesn't belong.  This means
the driver private data won't get reset to NULL.  It shouldn't cause
any problems, since the private data is undefined when no driver is
bound.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/buffer.c

@@ -104,7 +104,7 @@ void *hcd_buffer_alloc (
 	dma_addr_t		*dma
 )
 {
-	struct usb_hcd		*hcd = bus->hcpriv;
+	struct usb_hcd		*hcd = bus_to_hcd(bus);
 	int 			i;
 
 	/* some USB hosts just use PIO */
@@ -127,7 +127,7 @@ void hcd_buffer_free (
 	dma_addr_t		dma
 )
 {
-	struct usb_hcd		*hcd = bus->hcpriv;
+	struct usb_hcd		*hcd = bus_to_hcd(bus);
 	int 			i;
 
 	if (!addr)

drivers/usb/core/hcd.c

@@ -664,31 +664,6 @@ static int usb_rh_urb_dequeue (struct usb_hcd *hcd, struct urb *urb)
 
 /*-------------------------------------------------------------------------*/
 
-/* exported only within usbcore */
-struct usb_bus *usb_bus_get(struct usb_bus *bus)
-{
-	if (bus)
-		kref_get(&bus->kref);
-	return bus;
-}
-
-static void usb_host_release(struct kref *kref)
-{
-	struct usb_bus *bus = container_of(kref, struct usb_bus, kref);
-
-	if (bus->release)
-		bus->release(bus);
-}
-
-/* exported only within usbcore */
-void usb_bus_put(struct usb_bus *bus)
-{
-	if (bus)
-		kref_put(&bus->kref, usb_host_release);
-}
-
-/*-------------------------------------------------------------------------*/
-
 static struct class *usb_host_class;
 
 int usb_host_init(void)
@@ -720,15 +695,12 @@ static void usb_bus_init (struct usb_bus *bus)
 	bus->devnum_next = 1;
 
 	bus->root_hub = NULL;
-	bus->hcpriv = NULL;
 	bus->busnum = -1;
 	bus->bandwidth_allocated = 0;
 	bus->bandwidth_int_reqs  = 0;
 	bus->bandwidth_isoc_reqs = 0;
 
 	INIT_LIST_HEAD (&bus->bus_list);
-
-	kref_init(&bus->kref);
 }
 
 /*-------------------------------------------------------------------------*/
@@ -1081,7 +1053,7 @@ static void urb_unlink (struct urb *urb)
 int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
 {
 	int			status;
-	struct usb_hcd		*hcd = urb->dev->bus->hcpriv;
+	struct usb_hcd		*hcd = bus_to_hcd(urb->dev->bus);
 	struct usb_host_endpoint *ep;
 	unsigned long		flags;
 
@@ -1189,7 +1161,8 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
 /* called in any context */
 int usb_hcd_get_frame_number (struct usb_device *udev)
 {
-	struct usb_hcd	*hcd = (struct usb_hcd *)udev->bus->hcpriv;
+	struct usb_hcd	*hcd = bus_to_hcd(udev->bus);
+
 	if (!HC_IS_RUNNING (hcd->state))
 		return -ESHUTDOWN;
 	return hcd->driver->get_frame_number (hcd);
@@ -1262,7 +1235,7 @@ int usb_hcd_unlink_urb (struct urb *urb, int status)
 	spin_lock (&hcd_data_lock);
 
 	sys = &urb->dev->dev;
-	hcd = urb->dev->bus->hcpriv;
+	hcd = bus_to_hcd(urb->dev->bus);
 	if (hcd == NULL) {
 		retval = -ENODEV;
 		goto done;
@@ -1333,7 +1306,7 @@ void usb_hcd_endpoint_disable (struct usb_device *udev,
 	struct usb_hcd		*hcd;
 	struct urb		*urb;
 
-	hcd = udev->bus->hcpriv;
+	hcd = bus_to_hcd(udev->bus);
 
 	WARN_ON (!HC_IS_RUNNING (hcd->state) && hcd->state != HC_STATE_HALT &&
 			udev->state != USB_STATE_NOTATTACHED);
@@ -1673,14 +1646,6 @@ EXPORT_SYMBOL_GPL (usb_hc_died);
 
 /*-------------------------------------------------------------------------*/
 
-static void hcd_release (struct usb_bus *bus)
-{
-	struct usb_hcd *hcd;
-
-	hcd = container_of(bus, struct usb_hcd, self);
-	kfree(hcd);
-}
-
 /**
  * usb_create_hcd - create and initialize an HCD structure
  * @driver: HC driver that will use this hcd
@@ -1705,10 +1670,9 @@ struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
 		return NULL;
 	}
 	dev_set_drvdata(dev, hcd);
+	kref_init(&hcd->kref);
 
 	usb_bus_init(&hcd->self);
-	hcd->self.hcpriv = hcd;
-	hcd->self.release = &hcd_release;
 	hcd->self.controller = dev;
 	hcd->self.bus_name = bus_name;
 	hcd->self.uses_dma = (dev->dma_mask != NULL);
@@ -1725,10 +1689,25 @@ struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
 }
 EXPORT_SYMBOL (usb_create_hcd);
 
+static void hcd_release (struct kref *kref)
+{
+	struct usb_hcd *hcd = container_of (kref, struct usb_hcd, kref);
+
+	kfree(hcd);
+}
+
+struct usb_hcd *usb_get_hcd (struct usb_hcd *hcd)
+{
+	if (hcd)
+		kref_get (&hcd->kref);
+	return hcd;
+}
+EXPORT_SYMBOL (usb_get_hcd);
+
 void usb_put_hcd (struct usb_hcd *hcd)
 {
-	dev_set_drvdata(hcd->self.controller, NULL);
-	usb_bus_put(&hcd->self);
+	if (hcd)
+		kref_put (&hcd->kref, hcd_release);
 }
 EXPORT_SYMBOL (usb_put_hcd);
 

drivers/usb/core/hcd.h

@@ -55,12 +55,13 @@
 
 /*-------------------------------------------------------------------------*/
 
-struct usb_hcd {	/* usb_bus.hcpriv points to this */
+struct usb_hcd {
 
 	/*
 	 * housekeeping
 	 */
 	struct usb_bus		self;		/* hcd is-a bus */
+	struct kref		kref;		/* reference counter */
 
 	const char		*product_desc;	/* product/vendor string */
 	char			irq_descr[24];	/* driver + bus # */
@@ -129,8 +130,10 @@ static inline struct usb_bus *hcd_to_bus (struct usb_hcd *hcd)
 	return &hcd->self;
 }
 
-
-// urb.hcpriv is really hardware-specific
+static inline struct usb_hcd *bus_to_hcd (struct usb_bus *bus)
+{
+	return container_of(bus, struct usb_hcd, self);
+}
 
 struct hcd_timeout {	/* timeouts we allocate */
 	struct list_head	timeout_list;
@@ -210,6 +213,7 @@ extern int usb_hcd_get_frame_number (struct usb_device *udev);
 
 extern struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
 		struct device *dev, char *bus_name);
+extern struct usb_hcd *usb_get_hcd (struct usb_hcd *hcd);
 extern void usb_put_hcd (struct usb_hcd *hcd);
 extern int usb_add_hcd(struct usb_hcd *hcd,
 		unsigned int irqnum, unsigned long irqflags);
@@ -356,9 +360,6 @@ extern struct list_head usb_bus_list;
 extern struct mutex usb_bus_list_lock;
 extern wait_queue_head_t usb_kill_urb_queue;
 
-extern struct usb_bus *usb_bus_get (struct usb_bus *bus);
-extern void usb_bus_put (struct usb_bus *bus);
-
 extern void usb_enable_root_hub_irq (struct usb_bus *bus);
 
 extern int usb_find_interface_driver (struct usb_device *dev,

drivers/usb/core/usb.c

@@ -169,7 +169,7 @@ static void usb_release_dev(struct device *dev)
 	udev = to_usb_device(dev);
 
 	usb_destroy_configuration(udev);
-	usb_bus_put(udev->bus);
+	usb_put_hcd(bus_to_hcd(udev->bus));
 	kfree(udev->product);
 	kfree(udev->manufacturer);
 	kfree(udev->serial);
@@ -197,8 +197,7 @@ usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
 	if (!dev)
 		return NULL;
 
-	bus = usb_bus_get(bus);
-	if (!bus) {
+	if (!usb_get_hcd(bus_to_hcd(bus))) {
 		kfree(dev);
 		return NULL;
 	}

drivers/usb/gadget/dummy_hcd.c

@@ -889,11 +889,9 @@ EXPORT_SYMBOL (net2280_set_fifo_mode);
 static void
 dummy_gadget_release (struct device *dev)
 {
-#if 0		/* usb_bus_put isn't EXPORTed! */
 	struct dummy	*dum = gadget_dev_to_dummy (dev);
 
-	usb_bus_put (&dummy_to_hcd (dum)->self);
-#endif
+	usb_put_hcd (dummy_to_hcd (dum));
 }
 
 static int dummy_udc_probe (struct platform_device *pdev)
@@ -915,9 +913,7 @@ static int dummy_udc_probe (struct platform_device *pdev)
 	if (rc < 0)
 		return rc;
 
-#if 0		/* usb_bus_get isn't EXPORTed! */
-	usb_bus_get (&dummy_to_hcd (dum)->self);
-#endif
+	usb_get_hcd (dummy_to_hcd (dum));
 
 	platform_set_drvdata (pdev, dum);
 	device_create_file (&dum->gadget.dev, &dev_attr_function);

drivers/usb/host/ehci-dbg.c

@@ -451,7 +451,7 @@ show_async (struct class_device *class_dev, char *buf)
 	*buf = 0;
 
 	bus = class_get_devdata(class_dev);
-	hcd = bus->hcpriv;
+	hcd = bus_to_hcd(bus);
 	ehci = hcd_to_ehci (hcd);
 	next = buf;
 	size = PAGE_SIZE;
@@ -497,7 +497,7 @@ show_periodic (struct class_device *class_dev, char *buf)
 	seen_count = 0;
 
 	bus = class_get_devdata(class_dev);
-	hcd = bus->hcpriv;
+	hcd = bus_to_hcd(bus);
 	ehci = hcd_to_ehci (hcd);
 	next = buf;
 	size = PAGE_SIZE;
@@ -634,7 +634,7 @@ show_registers (struct class_device *class_dev, char *buf)
 	static char		label [] = "";
 
 	bus = class_get_devdata(class_dev);
-	hcd = bus->hcpriv;
+	hcd = bus_to_hcd(bus);
 	ehci = hcd_to_ehci (hcd);
 	next = buf;
 	size = PAGE_SIZE;

drivers/usb/host/ohci-dbg.c

@@ -477,7 +477,7 @@ show_async (struct class_device *class_dev, char *buf)
 	unsigned long		flags;
 
 	bus = class_get_devdata(class_dev);
-	hcd = bus->hcpriv;
+	hcd = bus_to_hcd(bus);
 	ohci = hcd_to_ohci(hcd);
 
 	/* display control and bulk lists together, for simplicity */
@@ -510,7 +510,7 @@ show_periodic (struct class_device *class_dev, char *buf)
 	seen_count = 0;
 
 	bus = class_get_devdata(class_dev);
-	hcd = bus->hcpriv;
+	hcd = bus_to_hcd(bus);
 	ohci = hcd_to_ohci(hcd);
 	next = buf;
 	size = PAGE_SIZE;
@@ -607,7 +607,7 @@ show_registers (struct class_device *class_dev, char *buf)
 	u32			rdata;
 
 	bus = class_get_devdata(class_dev);
-	hcd = bus->hcpriv;
+	hcd = bus_to_hcd(bus);
 	ohci = hcd_to_ohci(hcd);
 	regs = ohci->regs;
 	next = buf;

drivers/usb/mon/mon_main.c

@@ -265,7 +265,6 @@ static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
 	ubus->mon_bus = NULL;
 	mbus->u_bus = NULL;
 	mb();
-	// usb_bus_put(ubus);
 }
 
 /*
@@ -297,10 +296,9 @@ static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus)
 	INIT_LIST_HEAD(&mbus->r_list);
 
 	/*
-	 * This usb_bus_get here is superfluous, because we receive
-	 * a notification if usb_bus is about to be removed.
+	 * We don't need to take a reference to ubus, because we receive
+	 * a notification if the bus is about to be removed.
 	 */
-	// usb_bus_get(ubus);
 	mbus->u_bus = ubus;
 	ubus->mon_bus = mbus;
 

include/linux/usb.h

@@ -280,7 +280,6 @@ struct usb_bus {
 	struct usb_devmap devmap;	/* device address allocation map */
 	struct usb_device *root_hub;	/* Root hub */
 	struct list_head bus_list;	/* list of busses */
-	void *hcpriv;                   /* Host Controller private data */
 
 	int bandwidth_allocated;	/* on this bus: how much of the time
 					 * reserved for periodic (intr/iso)
@@ -295,8 +294,6 @@ struct usb_bus {
 	struct dentry *usbfs_dentry;	/* usbfs dentry entry for the bus */
 
 	struct class_device *class_dev;	/* class device for this bus */
-	struct kref kref;		/* reference counting for this bus */
-	void (*release)(struct usb_bus *bus);
 
 #if defined(CONFIG_USB_MON)
 	struct mon_bus *mon_bus;	/* non-null when associated */