From: Leonard Crestez <leonard.crestez@nxp.com>
Date: Tue, 14 Jan 2020 22:25:46 +0200
Subject: perf/imx_ddr: Fix cpu hotplug state cleanup
Git-commit: 9ee68b314e9aa63ed11b98beb8a68810b8234dcf
Patch-mainline: v5.6-rc1
References: jsc#SLE-16106

This driver allocates a dynamic cpu hotplug state but never releases it.
If reloaded in a loop it will quickly trigger a WARN message:

	"No more dynamic states available for CPU hotplug"

Fix by calling cpuhp_remove_multi_state on remove like several other
perf pmu drivers.

Also fix the cleanup logic on probe error paths: add the missing
cpuhp_remove_multi_state call and properly check the return value from
cpuhp_state_add_instant_nocalls.

Fixes: 9a66d36cc7ac ("drivers/perf: imx_ddr: Add DDR performance counter support to perf")
Acked-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 drivers/perf/fsl_imx8_ddr_perf.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/perf/fsl_imx8_ddr_perf.c b/drivers/perf/fsl_imx8_ddr_perf.c
index 55083c67b2bb..95dca2cb5265 100644
--- a/drivers/perf/fsl_imx8_ddr_perf.c
+++ b/drivers/perf/fsl_imx8_ddr_perf.c
@@ -633,13 +633,17 @@ static int ddr_perf_probe(struct platform_device *pdev)
 
 	if (ret < 0) {
 		dev_err(&pdev->dev, "cpuhp_setup_state_multi failed\n");
-		goto ddr_perf_err;
+		goto cpuhp_state_err;
 	}
 
 	pmu->cpuhp_state = ret;
 
 	/* Register the pmu instance for cpu hotplug */
-	cpuhp_state_add_instance_nocalls(pmu->cpuhp_state, &pmu->node);
+	ret = cpuhp_state_add_instance_nocalls(pmu->cpuhp_state, &pmu->node);
+	if (ret) {
+		dev_err(&pdev->dev, "Error %d registering hotplug\n", ret);
+		goto cpuhp_instance_err;
+	}
 
 	/* Request irq */
 	irq = of_irq_get(np, 0);
@@ -673,9 +677,10 @@ static int ddr_perf_probe(struct platform_device *pdev)
 	return 0;
 
 ddr_perf_err:
-	if (pmu->cpuhp_state)
-		cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);
-
+	cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);
+cpuhp_instance_err:
+	cpuhp_remove_multi_state(pmu->cpuhp_state);
+cpuhp_state_err:
 	ida_simple_remove(&ddr_ida, pmu->id);
 	dev_warn(&pdev->dev, "i.MX8 DDR Perf PMU failed (%d), disabled\n", ret);
 	return ret;
@@ -686,6 +691,7 @@ static int ddr_perf_remove(struct platform_device *pdev)
 	struct ddr_pmu *pmu = platform_get_drvdata(pdev);
 
 	cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);
+	cpuhp_remove_multi_state(pmu->cpuhp_state);
 	irq_set_affinity_hint(pmu->irq, NULL);
 
 	perf_pmu_unregister(&pmu->pmu);