[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/include/linux/usb.h b/include/linux/usb.h
index 2714814..46dc042 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -329,8 +329,6 @@
struct usb_tt *tt; /* low/full speed dev, highspeed hub */
int ttport; /* device port on that tt hub */
- struct semaphore serialize;
-
unsigned int toggle[2]; /* one bit for each endpoint
* ([0] = IN, [1] = OUT) */
@@ -377,11 +375,12 @@
extern struct usb_device *usb_get_dev(struct usb_device *dev);
extern void usb_put_dev(struct usb_device *dev);
-extern void usb_lock_device(struct usb_device *udev);
-extern int usb_trylock_device(struct usb_device *udev);
+/* USB device locking */
+#define usb_lock_device(udev) down(&(udev)->dev.sem)
+#define usb_unlock_device(udev) up(&(udev)->dev.sem)
+#define usb_trylock_device(udev) down_trylock(&(udev)->dev.sem)
extern int usb_lock_device_for_reset(struct usb_device *udev,
struct usb_interface *iface);
-extern void usb_unlock_device(struct usb_device *udev);
/* USB port reset for device reinitialization */
extern int usb_reset_device(struct usb_device *dev);