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    SubjectRe: Horrible regression with -CURRENT from "Don't busy-lock-loop in preemptable spinlocks" patch
    Chris Wedgwood writes:

    > +#define rwlock_is_write_locked(x) ((x)->lock == 0)

    AFAICS on i386 the lock word, although it goes to 0 when write-locked,
    can then go negative temporarily when another cpu tries to get a read
    or write lock. So I think this should be

    ((signed int)(x)->lock <= 0)

    (or the equivalent using atomic_read).

    Paul.
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