[net 4/5] can: c_can: c_can_power_up(): fix error handling

[Marc Kleine-Budde]

From: Zhang Qilong <zhangqilo...@huawei.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 <zhangqilo...@huawei.com>
Link: https://lore.kernel.org/r/20201128133922.3276973-2-zhangqilo...@huawei.com
[mkl: return "0" instead of "ret"]
Signed-off-by: Marc Kleine-Budde <m...@pengutronix.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