On Saturday 31 July 2010 21:48:05 Greg KH wrote: > On Sat, Jul 31, 2010 at 06:24:33PM +0200, Christian Lamparter wrote: > > (No maintainer for usb/core?) > > Yes, did you look in the MAINTAINERS file? Or use > scripts/get_maintainer.pl? It should show you the proper name... Ah, I was looking for something with USB and CORE, or /usb/core. Anyway, doesn't matter anymore, since you've added :-) > > First a bit of background: > > > > I'm developing a driver for the AR9170 USB 802.11n Wireless device. > > And if you are interested in this thing, the driver code + fw is available at: > > http://www.kernel.org/pub/linux/kernel/people/chr/carl9170/carl9170-1.7.4-pre/ > > > > Now, back to my problem: > > > > The driver uses a sophisticated 3 anchor layout: > > 1. rx_pool => a pool of prepared urbs, which can be > > submitted to the device anytime. > > Why a pool? Is allocating new ones somehow too slow? If so, why? Because the device uses some sort of streaming technology. Basically, it aggregates multiple frames/command responses and traps into a single, large transfer (which can be as large as 32K) (Note: the _current_ limit is at 8K, but the HW supports up to 32K) So, the usual replacement buffers on-demand stuff is not an option. > > 2. rx_work => storage for received urbs, which will be > > processed in the rx tasklet. > > > > 3. rx_anchor => all active rx urbs (i.e.: those which have been > > submitted to the device) > > > > --- > > diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c > > index 7c05555..93f8f4c 100644 > > --- a/drivers/usb/core/urb.c > > +++ b/drivers/usb/core/urb.c > > @@ -137,6 +137,16 @@ void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) > > } > > EXPORT_SYMBOL_GPL(usb_anchor_urb); > > > > +static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor) > > +{ > > + urb->anchor = NULL; > > + > > + list_del(&urb->anchor_list); > > + usb_put_urb(urb); > > + if (list_empty(&anchor->urb_list)) > > + wake_up(&anchor->wait); > > You are calling wake_up with a spinlock held, is that ok? > uhh, I know that you can't sleep while holding a spinlock. But I haven't read anything about why you can't call wake_up (or complete for that matter?) while holding a lock. I see you point, though. Do you have an idea for an alternative way without making a real mess of it? Regards, Chr -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
