netdev - [net 4/5] can: c_can: c_can_power

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Date:   Mon, 30 Nov 2020 13:53:06 +0100
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
        kernel@...gutronix.de, Zhang Qilong <zhangqilong3@...wei.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [net 4/5] can: c_can: c_can_power_up(): fix error handling

From: Zhang Qilong <zhangqilong3@...wei.com>

In the error handling in c_can_power_up(), there are two bugs:

1) c_can_pm_runtime_get_sync() will increase usage counter if device is not
   empty. Forgetting to call c_can_pm_runtime_put_sync() will result in a
   reference leak here.

2) c_can_reset_ram() operation will set start bit when enable is true. We
   should clear it in the error handling.

We fix it by adding c_can_pm_runtime_put_sync() for 1), and
c_can_reset_ram(enable is false) for 2) in the error handling.

Fixes: 8212003260c60 ("can: c_can: Add d_can suspend resume support")
Fixes: 52cde85acc23f ("can: c_can: Add d_can raminit support")
Signed-off-by: Zhang Qilong <zhangqilong3@...wei.com>
Link: https://lore.kernel.org/r/20201128133922.3276973-2-zhangqilong3@huawei.com
[mkl: return "0" instead of "ret"]
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/c_can/c_can.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 1ccdbe89585b..1a9e9b9a4bf6 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -1295,12 +1295,22 @@ int c_can_power_up(struct net_device *dev)
 				time_after(time_out, jiffies))
 		cpu_relax();
 
-	if (time_after(jiffies, time_out))
-		return -ETIMEDOUT;
+	if (time_after(jiffies, time_out)) {
+		ret = -ETIMEDOUT;
+		goto err_out;
+	}
 
 	ret = c_can_start(dev);
-	if (!ret)
-		c_can_irq_control(priv, true);
+	if (ret)
+		goto err_out;
+
+	c_can_irq_control(priv, true);
+
+	return 0;
+
+err_out:
+	c_can_reset_ram(priv, false);
+	c_can_pm_runtime_put_sync(priv);
 
 	return ret;
 }
-- 
2.29.2