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>

1 files changed, 14 insertions, 10 deletions

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 87975b5dda94..7a8209e73199 100644
--- 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;