linux-kernel - Re: [PATCH v4 2/5] soc: qcom: rpmh-rsc: We aren't notified of our own failure w/ NOTIFY

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Message-ID: <158769590404.135303.4049749400685142607@swboyd.mtv.corp.google.com>
Date:   Thu, 23 Apr 2020 19:38:24 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Douglas Anderson <dianders@...omium.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        rafael.j.wysocki@...el.com
Cc:     mka@...omium.org, mkshah@...eaurora.org, evgreen@...omium.org,
        Douglas Anderson <dianders@...omium.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/5] soc: qcom: rpmh-rsc: We aren't notified of our own failure w/ NOTIFY_BAD

Quoting Douglas Anderson (2020-04-22 14:55:00)
> 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@...omium.org>
> ---

Reported-by: Stephen Boyd <swboyd@...omium.org>
Reviewed-by: Stephen Boyd <swboyd@...omium.org>