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>

8 files changed, 44 insertions, 71 deletions

diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
index f4f4ef0f377a..840442a25b61 100644
--- a/drivers/usb/core/buffer.c
+++ b/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)
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 0cc14206920a..9dfc812de034 100644
--- a/drivers/usb/core/hcd.c
+++ b/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 @@ done:
 /* 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);
 
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 83e229914797..7a2bcba2ae61 100644
--- a/drivers/usb/core/hcd.h
+++ b/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,
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 7ab9d29215f8..b0c0a993338f 100644
--- a/drivers/usb/core/usb.c
+++ b/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;
         }
diff --git a/drivers/usb/gadget/dummy_hcd.c b/drivers/usb/gadget/dummy_hcd.c
index 7d1c22c34957..fdab97a27c08 100644
--- a/drivers/usb/gadget/dummy_hcd.c
+++ b/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);
diff --git a/drivers/usb/host/ehci-dbg.c b/drivers/usb/host/ehci-dbg.c
index 65ac9fef3a7c..215ce6d06394 100644
--- a/drivers/usb/host/ehci-dbg.c
+++ b/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;
diff --git a/drivers/usb/host/ohci-dbg.c b/drivers/usb/host/ohci-dbg.c
index da52609a9290..534d07dcb824 100644
--- a/drivers/usb/host/ohci-dbg.c
+++ b/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;
diff --git a/drivers/usb/mon/mon_main.c b/drivers/usb/mon/mon_main.c
index 275a66f83058..e0ed36cdfd8b 100644
--- a/drivers/usb/mon/mon_main.c
+++ b/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;