linux-kernel - [PATCH v4 1/5] soc: qcom: rpmh-rsc: Corrently ignore CPU_CLUSTER

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Date:   Wed, 22 Apr 2020 14:54:59 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        rafael.j.wysocki@...el.com, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     mka@...omium.org, swboyd@...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: [PATCH v4 1/5] soc: qcom: rpmh-rsc: Corrently ignore CPU_CLUSTER_PM notifications

Our switch statement doesn't have entries for CPU_CLUSTER_PM_ENTER,
CPU_CLUSTER_PM_ENTER_FAILED, and CPU_CLUSTER_PM_EXIT and doesn't have
a default.  This means that we'll try to do a flush in those cases but
we won't necessarily be the last CPU down.  That's not so ideal since
our (lack of) locking assumes we're on the last CPU.

Luckily this isn't as big a problem as you'd think since (at least on
the SoC I tested) we don't get these notifications except on full
system suspend.  ...and on full system suspend we get them on the last
CPU down.  That means that the worst problem we hit is flushing twice.
Still, it's good to make it correct.

Fixes: 985427f997b6 ("soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches")
Reported-by: Stephen Boyd <swboyd@...omium.org>
Signed-off-by: Douglas Anderson <dianders@...omium.org>
---

Changes in v4:
- ("...Corrently ignore CPU_CLUSTER_PM notifications") split out for v4.

Changes in v3: None
Changes in v2: None

 drivers/soc/qcom/rpmh-rsc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index a9e15699f55f..3571a99fc839 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -806,6 +806,8 @@ static int rpmh_rsc_cpu_pm_callback(struct notifier_block *nfb,
 	case CPU_PM_EXIT:
 		cpumask_clear_cpu(smp_processor_id(), &drv->cpus_entered_pm);
 		goto exit;
+	default:
+		return NOTIFY_DONE;
 	}

 	ret = rpmh_rsc_ctrlr_is_busy(drv);
-- 
2.26.1.301.g55bc3eb7cb9-goog