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    SubjectRe: [PATCH v4 2/5] soc: qcom: rpmh-rsc: We aren't notified of our own failure w/ NOTIFY_BAD
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    Date
    Reviewed-by: Maulik Shah <mkshah@codeaurora.org>

    Thanks,
    Maulik

    On 4/23/2020 3:25 AM, Douglas Anderson wrote:
    > When a PM Notifier returns NOTIFY_BAD it doesn't get called with
    > CPU_PM_ENTER_FAILED. It only get called for CPU_PM_ENTER_FAILED if
    > someone else (further down the notifier chain) returns NOTIFY_BAD.
    >
    > Handle this case by taking our CPU out of the list of ones that have
    > entered PM. Without this it's possible we could detect that the last
    > CPU went down (and we would flush) even if some CPU was alive. That's
    > not good since our flushing routines currently assume they're running
    > on the last CPU for mutual exclusion.
    >
    > Fixes: 985427f997b6 ("soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches")
    > Signed-off-by: Douglas Anderson <dianders@chromium.org>
    > ---
    >
    > Changes in v4:
    > - ("...We aren't notified of our own failure...") split out for v4.
    >
    > Changes in v3: None
    > Changes in v2: None
    >
    > drivers/soc/qcom/rpmh-rsc.c | 4 ++++
    > 1 file changed, 4 insertions(+)
    >
    > diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
    > index 3571a99fc839..e540e49fd61c 100644
    > --- a/drivers/soc/qcom/rpmh-rsc.c
    > +++ b/drivers/soc/qcom/rpmh-rsc.c
    > @@ -823,6 +823,10 @@ static int rpmh_rsc_cpu_pm_callback(struct notifier_block *nfb,
    > ret = NOTIFY_OK;
    >
    > exit:
    > + if (ret == NOTIFY_BAD)
    > + /* We won't be called w/ CPU_PM_ENTER_FAILED */
    > + cpumask_clear_cpu(smp_processor_id(), &drv->cpus_entered_pm);
    > +
    > spin_unlock(&drv->pm_lock);
    > return ret;
    > }

    --
    QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

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