rwsem: test for no active locks in __rwsem_do_wake undo code
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From: David Howells on 12 May 2010 06:50 Michel Lespinasse <walken(a)google.com> wrote: > If there are no active threasd using a semaphore, it is always correct to > unqueue blocked threads. This seems to be what was intended in the undo code. > > What was done instead, was to look for a sem count of zero - this is an > impossible situation, given that at least one thread is known to be queued > on the semaphore. The code might be correct as written, but it's hard to > reason about and it's not what was intended (otherwise the goto out would > have been unconditional). > > Go for checking the active count - the alternative is not worth the headache. I think this is a definite bug fix, so I've sent it upstream in advance. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |