net: ethernet: fs_enet: only protect the .restart() call in .adjust_link

When .adjust_link() gets called, it runs in thread context, with the
phydev->lock held. We only need to protect the fep->fecp/fccp/sccp
register that are accessed within the .restart() function from
concurrent access from the interrupts.

These registers are being protected by the fep->lock spinlock, so we can
move the spinlock protection around the .restart() call instead of the
entire adjust_link() call. By doing so, we can simplify further the
.adjust_link() callback and avoid the intermediate helper.
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c

@@ -607,10 +607,11 @@ static void fs_timeout(struct net_device *dev, unsigned int txqueue)
 }
 
 /* generic link-change handler - should be sufficient for most cases */
-static void generic_adjust_link(struct  net_device *dev)
+static void fs_adjust_link(struct  net_device *dev)
 {
 	struct fs_enet_private *fep = netdev_priv(dev);
 	struct phy_device *phydev = dev->phydev;
+	unsigned long flags;
 	int new_state = 0;
 
 	if (phydev->link) {
@@ -630,8 +631,11 @@ static void generic_adjust_link(struct  net_device *dev)
 			fep->oldlink = 1;
 		}
 
-		if (new_state)
+		if (new_state) {
+			spin_lock_irqsave(&fep->lock, flags);
 			fep->ops->restart(dev);
+			spin_unlock_irqrestore(&fep->lock, flags);
+		}
 	} else if (fep->oldlink) {
 		new_state = 1;
 		fep->oldlink = 0;
@@ -643,16 +647,6 @@ static void generic_adjust_link(struct  net_device *dev)
 		phy_print_status(phydev);
 }
 
-static void fs_adjust_link(struct net_device *dev)
-{
-	struct fs_enet_private *fep = netdev_priv(dev);
-	unsigned long flags;
-
-	spin_lock_irqsave(&fep->lock, flags);
-	generic_adjust_link(dev);
-	spin_unlock_irqrestore(&fep->lock, flags);
-}
-
 static int fs_init_phy(struct net_device *dev)
 {
 	struct fs_enet_private *fep = netdev_priv(dev);