Messages in this thread | | | Date | Fri, 21 May 2004 18:04:46 -0400 | From | nardelli <> | Subject | Re: [linux-usb-devel] [PATCH] visor: Fix Oops on disconnect |
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nardelli wrote: > Greg KH wrote: > > >>> @@ -456,7 +460,8 @@ static void visor_close (struct usb_seri >>> return; >>> >>> /* shutdown our urbs */ >>> - usb_unlink_urb (port->read_urb); >>> + if (port->read_urb) >>> + usb_unlink_urb (port->read_urb); >> >> >> I really do not think these extra checks for read_urb all of the place >> need to be added. We take care of it in the open() call, right? >> > > Yes - less clutter and more efficient too. >
Maybe I spoke too soon here. We have 1 bulk in, 2 bulk out, and 1 interrupt in endpoint, which by the logic in usb-serial, translates to 2 ports. Only one of those ports can have a read_urb associated with it, unless we want to do some really fancy juggling. This means that we're going to have a port that does not have a valid read_urb associated with it, even after open(). In this case, any attempt to read from /dev/ttyUSB0 (even if it is useless) would result in a null pointer access violation unless there is some form of protection around it. Not permitting reads on this port would get around this, but putting 'if' checks around access to read_urb is probably much simpler.
I'm at a loss why this device has an uneven number of bulk in and bulk out endpoints.
Any thoughts?
-- Joe Nardelli jnardelli@infosciences.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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