can: flexcan: fix failure handling of pm_runtime_get_sync()

[ Upstream commit b7ee5bc3e1006433601a058a6a7c24c5272635f4 ]

pm_runtime_get_sync() will increment pm usage at first and it will resume the
device later. If runtime of the device has error or device is in inaccessible
state(or other error state), resume operation will fail. If we do not call put
operation to decrease the reference, it will result in reference leak in the
two functions flexcan_get_berr_counter() and flexcan_open().

Moreover, this device cannot enter the idle state and always stay busy or other
non-idle state later. So we should fix it through adding
pm_runtime_put_noidle().

Fixes: ca10989632d88 ("can: flexcan: implement can Runtime PM")
Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Link: https://lore.kernel.org/r/20201108083000.2599705-1-zhangqilong3@huawei.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 130f3022d339658a573ee45562900f553a5f8388..b22cd8d14716a6c40a8f58ee3b5ba3bca425ac31 100644 (file)
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -614,8 +614,10 @@ static int flexcan_get_berr_counter(const struct net_device *dev,
        int err;
 
        err = pm_runtime_get_sync(priv->dev);
-       if (err < 0)
+       if (err < 0) {
+               pm_runtime_put_noidle(priv->dev);
                return err;
+       }
 
        err = __flexcan_get_berr_counter(dev, bec);
 
@@ -1282,8 +1284,10 @@ static int flexcan_open(struct net_device *dev)
        int err;
 
        err = pm_runtime_get_sync(priv->dev);
-       if (err < 0)
+       if (err < 0) {
+               pm_runtime_put_noidle(priv->dev);
                return err;
+       }
 
        err = open_candev(dev);
        if (err)