On Wednesday 09 March 2005 00:59, Greg KH wrote:
> On Tue, Mar 08, 2005 at 08:57:06PM -0500, Nick Sillik wrote:
> > Do I need to use a spinlock, or should I just impliment a simple up/down
> > lock?
>
> Depends on how long you are going to need to hold it, and what you are
> going to be doing while holding the lock.
>
It looks like spinlock will be fine - at connect time it has to be taken
while adding to the list, at disconnect time it has to be taken while
searching list and removing element.
Btw, since there can be only one entry for a device in that list you
can rearrange code like this:
wrap = NULL;
spin_lock(&onetouch_list_lock);
list_for_each_entry(entry, &onetouch_list, list) {
if (entry->onetouch->udev == udev) {
wrap = entry;
list_del(&wrap->list);
break;
}
}
spin_unlock(&onetouch_list_lock);
if (wrap) {
onetouh = wrap->onetouch;
US_DEBUGP("device found: %s. Releasing\n", onetouch->phys);
usb_unlink_urb(onetouch->irq);
input_unregister_device(&onetouch->dev);
usb_free_urb(onetouch->irq);
...
Btw, why don't you drop that "wrap" structure and put list_head right into
usb_onetouch structure?
--
Dmitry
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