net: fec: Fix sparse warnings with different lock contexts for basic block

reproduce:
make  ARCH=arm C=1 2>fec.txt drivers/net/ethernet/freescale/fec_main.o
cat fec.txt

sparse warnings:
drivers/net/ethernet/freescale/fec_main.c:2916:12: warning: context imbalance
in 'fec_set_features' - different lock contexts for basic block

Christopher Li suggest to change as below:
	if (need_lock) {
		lock();
		do_something_real();
		unlock();
	} else {
		do_something_real();
	}

Reported-by: Fabio Estevam <festevam@gmail.com>
Suggested-by: Christopher Li <sparse@chrisli.org>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 87975b5..7a8209e 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -2912,20 +2912,12 @@ static void fec_poll_controller(struct net_device *dev)
 #endif
 
 #define FEATURES_NEED_QUIESCE NETIF_F_RXCSUM
-
-static int fec_set_features(struct net_device *netdev,
+static inline void fec_enet_set_netdev_features(struct net_device *netdev,
        netdev_features_t features)
 {
        struct fec_enet_private *fep = netdev_priv(netdev);
        netdev_features_t changed = features ^ netdev->features;
 
-       /* Quiesce the device if necessary */
-       if (netif_running(netdev) && changed & FEATURES_NEED_QUIESCE) {
-               napi_disable(&fep->napi);
-               netif_tx_lock_bh(netdev);
-               fec_stop(netdev);
-       }
-
        netdev->features = features;
 
        /* Receive checksum has been changed */
@@ -2935,13 +2927,25 @@ static int fec_set_features(struct net_device *netdev,
                else
                        fep->csum_flags &= ~FLAG_RX_CSUM_ENABLED;
        }
+}
+
+static int fec_set_features(struct net_device *netdev,
+       netdev_features_t features)
+{
+       struct fec_enet_private *fep = netdev_priv(netdev);
+       netdev_features_t changed = features ^ netdev->features;
 
-       /* Resume the device after updates */
        if (netif_running(netdev) && changed & FEATURES_NEED_QUIESCE) {
+               napi_disable(&fep->napi);
+               netif_tx_lock_bh(netdev);
+               fec_stop(netdev);
+               fec_enet_set_netdev_features(netdev, features);
                fec_restart(netdev);
                netif_tx_wake_all_queues(netdev);
                netif_tx_unlock_bh(netdev);
                napi_enable(&fep->napi);
+       } else {
+               fec_enet_set_netdev_features(netdev, features);
        }
 
        return 0;