Messages in this thread |  | | Date | Tue, 22 Aug 2000 10:30:00 +0200 | From | Vojtech Pavlik <> | Subject | Re: Updated Linux 2.4 issues page |
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On Mon, Aug 21, 2000 at 04:30:04PM -0700, Greg KH wrote: > On Mon, Aug 21, 2000 at 04:13:00PM -0700, Dunlap, Randy wrote: > > > > usblp_read() and usblp_write() already use separate urbs > > for read vs. write and for each instance of the lp (minor). > > Can you give me a brief explanation of the problem? > > (and I'll look at David's dc2xx patch). > > >From what I understand, copy_to_user can sleep, then (for the usblp_read > function) the read can be called again, the data can be written to the > urb and submitted, then the previous copy_to_user wakes up, and tries to > resubmit the urb again with different data this time. Not good. > > Same thing for the usblp_write function.
IMHO that can't happen, because these devices are single-open only, that is only one process can be using then at once. So I can't imagine how it would be able to sleep (in copy_to_user) and reenter the read/write routines both at once.
-- Vojtech Pavlik SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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