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[PATCH] USB: Remove USB private semaphore

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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>
This commit is contained in:
Alan Stern 2005-11-17 17:10:32 -05:00 • committed by Greg Kroah-Hartman
parent 75318d2d7c
commit 9ad3d6ccf5
9 changed files with 37 additions and 154 deletions
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9
include/linux/usb.h
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@ -329,8 +329,6 @@ struct usb_device {
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 @@ struct usb_device {
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);