[PATCH] USB: Remove USB private semaphore

This patch (as605) removes the private udev->serialize semaphore,
relying instead on the locking provided by the embedded struct device's
semaphore.  The changes are confined to the core, except that the
usb_trylock_device routine now uses the return convention of
down_trylock rather than down_read_trylock (they return opposite values
for no good reason).

A couple of other associated changes are included as well:

	Now that we aren't concerned about HCDs that avoid using the
	hcd glue layer, usb_disconnect no longer needs to acquire the
	usb_bus_lock -- that can be done by usb_remove_hcd where it
	belongs.

	Devices aren't locked over the same scope of code in
	usb_new_device and hub_port_connect_change as they used to be.
	This shouldn't cause any trouble.

Along with the preceding driver core patch, this needs a lot of testing.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index da24c31..d16a0e8 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -857,9 +857,7 @@ static int register_root_hub (struct usb_device *usb_dev,
 		return (retval < 0) ? retval : -EMSGSIZE;
 	}
 
-	usb_lock_device (usb_dev);
 	retval = usb_new_device (usb_dev);
-	usb_unlock_device (usb_dev);
 	if (retval) {
 		usb_dev->bus->root_hub = NULL;
 		dev_err (parent_dev, "can't register root hub for %s, %d\n",
@@ -1891,7 +1889,10 @@ void usb_remove_hcd(struct usb_hcd *hcd)
 	spin_lock_irq (&hcd_root_hub_lock);
 	hcd->rh_registered = 0;
 	spin_unlock_irq (&hcd_root_hub_lock);
+
+	down(&usb_bus_list_lock);
 	usb_disconnect(&hcd->self.root_hub);
+	up(&usb_bus_list_lock);
 
 	hcd->poll_rh = 0;
 	del_timer_sync(&hcd->rh_timer);