[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>
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 @@
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 @@
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);