Messages in this thread |  | | | Date | Fri, 30 Jun 2006 01:52:51 -0700 | | From | Pete Zaitcev <> | | Subject | Re: [PATCH] Airprime driver improvements to allow full speed EvDO transfers |
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On Fri, 30 Jun 2006 00:10:21 -0700, Andrew Morton <akpm@osdl.org> wrote:
> > +static void airprime_read_bulk_callback(struct urb *urb, struct pt_regs *regs) >....... > > + /* should this use GFP_KERNEL? */ > > + result = usb_submit_urb(urb, GFP_ATOMIC); > > If possible, yep.
You can't be serious. It's a callback function we're discussing here, and you even quoted it.
> > + /* free up private structure? */ > > Yes please ;)
+1
> Is usb_serial_driver.write() really called in a context in which it is > forced to use GFP_ATOMIC?
There are cases when it is. It happens when a line discipline does it. The n_tty does it if the line is in cooked mode, which is the default. n_hdlc does it always, though I have no idea if this is applicable to airprime. I think PPP writes from a tasklet as well.
The idea to allocate a URB for every little user write bothers me as well. It was a dirty code thrown together quickly by someone who could not be bothered to use a circular buffer and two URBs. It was fine for the visor.c, but the Airprime is a higher performance card, and it can be used in a home gateway with a low-power CPU. I'm not happy.
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