Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 9 Apr 2001 22:43:53 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: rw_semaphores |
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On Tue, 10 Apr 2001, Tachino Nobuhiro wrote: > > I am not familiar with semaphore or x86, so this may not be correct, > but if the following sequence is possible, the writer can call wake_up() > before the reader calls add_wait_queue() and reader may sleep forever. > Is it possible?
The ordering is certainly possible, but if it happens, __down_read_failed() won't actually sleep, because it will notice that the value is positive and just return immediately. So it will do some unnecessary work (add itself to the wait-queue only to remove itself immediately again), but it will do the right thing.
Linus
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