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    SubjectRe: [PATCH] fault-inject: Avoid call to random32() if fault injection is disabled
    From
    2012/6/1 Anton Blanchard <anton@samba.org>:
    >
    > After enabling CONFIG_FAILSLAB I noticed random32 in profiles even
    > if slub fault injection wasn't enabled at runtime.
    >
    > should_fail forces a comparison against random32() even if
    > probability is 0:
    >
    >        if (attr->probability <= random32() % 100)
    >                return false;
    >
    > Add a check up front for probability == 0 and avoid all of the more
    > complicated checks.
    >
    > Signed-off-by: Anton Blanchard <anton@samba.org>
    > ---
    >
    > Index: linux-build/lib/fault-inject.c
    > ===================================================================
    > --- linux-build.orig/lib/fault-inject.c 2012-02-11 21:22:32.303459860 +1100
    > +++ linux-build/lib/fault-inject.c      2012-02-11 22:38:10.470977505 +1100
    > @@ -101,6 +101,10 @@ static inline bool fail_stacktrace(struc
    >
    >  bool should_fail(struct fault_attr *attr, ssize_t size)
    >  {
    > +       /* No need to check any other properties if the probability is 0 */
    > +       if (attr->probability == 0)
    > +               return false;
    > +
    >        if (attr->task_filter && !fail_task(attr, current))
    >                return false;
    >

    Looks good to me.

    Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
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