linux-kernel - [PATCH v2] iio: adc: mxs-lradc: fix the order of two cleanup operations

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Message-Id: <20230422133407.72908-1-jkluo@hust.edu.cn>
Date:   Sat, 22 Apr 2023 06:34:06 -0700
From:   Jiakai Luo <jkluo@...t.edu.cn>
To:     Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Lee Jones <lee.jones@...aro.org>, Marek Vasut <marex@...x.de>,
        Ksenija Stanojevic <ksenija.stanojevic@...il.com>
Cc:     hust-os-kernel-patches@...glegroups.com,
        Jiakai Luo <jkluo@...t.edu.cn>, linux-iio@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] iio: adc: mxs-lradc: fix the order of two cleanup operations

Smatch reports:
drivers/iio/adc/mxs-lradc-adc.c:766 mxs_lradc_adc_probe() warn:
missing unwind goto?

the order of three init operation:
1.mxs_lradc_adc_trigger_init
2.iio_triggered_buffer_setup
3.mxs_lradc_adc_hw_init

thus, the order of three cleanup operation should be:
1.mxs_lradc_adc_hw_stop
2.iio_triggered_buffer_cleanup
3.mxs_lradc_adc_trigger_remove

we exchange the order of two cleanup operations,
introducing the following differences:
1.if mxs_lradc_adc_trigger_init fails, returns directly;
2.if trigger_init succeeds but iio_triggered_buffer_setup fails,
goto err_trig and remove the trigger.

In addition, we also reorder the unwind that goes on in the
remove() callback to match the new ordering.

Fixes: 6dd112b9f85e ("iio: adc: mxs-lradc: Add support for ADC driver")
Signed-off-by: Jiakai Luo <jkluo@...t.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@...t.edu.cn>
---
The issue is found by static analysis and remains untested.
---
 drivers/iio/adc/mxs-lradc-adc.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/mxs-lradc-adc.c b/drivers/iio/adc/mxs-lradc-adc.c
index bca79a93cbe4..85882509b7d9 100644
--- a/drivers/iio/adc/mxs-lradc-adc.c
+++ b/drivers/iio/adc/mxs-lradc-adc.c
@@ -757,13 +757,13 @@ static int mxs_lradc_adc_probe(struct platform_device *pdev)
 
 	ret = mxs_lradc_adc_trigger_init(iio);
 	if (ret)
-		goto err_trig;
+		return ret;
 
 	ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
 					 &mxs_lradc_adc_trigger_handler,
 					 &mxs_lradc_adc_buffer_ops);
 	if (ret)
-		return ret;
+		goto err_trig;
 
 	adc->vref_mv = mxs_lradc_adc_vref_mv[lradc->soc];
 
@@ -801,9 +801,9 @@ static int mxs_lradc_adc_probe(struct platform_device *pdev)
 
 err_dev:
 	mxs_lradc_adc_hw_stop(adc);
-	mxs_lradc_adc_trigger_remove(iio);
-err_trig:
 	iio_triggered_buffer_cleanup(iio);
+err_trig:
+	mxs_lradc_adc_trigger_remove(iio);
 	return ret;
 }
 
@@ -814,8 +814,8 @@ static int mxs_lradc_adc_remove(struct platform_device *pdev)
 
 	iio_device_unregister(iio);
 	mxs_lradc_adc_hw_stop(adc);
-	mxs_lradc_adc_trigger_remove(iio);
 	iio_triggered_buffer_cleanup(iio);
+	mxs_lradc_adc_trigger_remove(iio);

 	return 0;
 }
-- 
2.17.1