sh_eth: fix bitbang memory leak

sh_mdio_init() allocates pointer to 'struct bb_info' but only stores it locally,
so that sh_mdio_release() can't free it on driver unload.  Add the pointer to
'struct bb_info' to 'struct sh_eth_private', so that sh_mdio_init() can save
'bitbang' variable for sh_mdio_release() to be able to free it later...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/sh_eth.c

@@ -2220,6 +2220,7 @@ static void sh_eth_tsu_init(struct sh_eth_private *mdp)
 /* MDIO bus release function */
 static int sh_mdio_release(struct net_device *ndev)
 {
+	struct sh_eth_private *mdp = netdev_priv(ndev);
 	struct mii_bus *bus = dev_get_drvdata(&ndev->dev);
 
 	/* unregister mdio bus */
@@ -2234,6 +2235,9 @@ static int sh_mdio_release(struct net_device *ndev)
 	/* free bitbang info */
 	free_mdio_bitbang(bus);
 
+	/* free bitbang memory */
+	kfree(mdp->bitbang);
+
 	return 0;
 }
 
@@ -2262,6 +2266,7 @@ static int sh_mdio_init(struct net_device *ndev, int id,
 	bitbang->ctrl.ops = &bb_ops;
 
 	/* MII controller setting */
+	mdp->bitbang = bitbang;
 	mdp->mii_bus = alloc_mdio_bitbang(&bitbang->ctrl);
 	if (!mdp->mii_bus) {
 		ret = -ENOMEM;

drivers/net/ethernet/renesas/sh_eth.h

@@ -705,6 +705,7 @@ struct sh_eth_private {
 	const u16 *reg_offset;
 	void __iomem *addr;
 	void __iomem *tsu_addr;
+	struct bb_info *bitbang;
 	u32 num_rx_ring;
 	u32 num_tx_ring;
 	dma_addr_t rx_desc_dma;