sunvnet: allow admin to set sunvnet MTU

This patch allows an admin to set the MTU on a sunvnet device to arbitrary
values between the minimum (68) and maximum (65535) IPv4 packet sizes.

Signed-off-by: David L Stevens <david.stevens@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 4 deletions

diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
index 8f5f4e3291a4..39804715bf22 100644
--- a/drivers/net/ethernet/sun/sunvnet.c
+++ b/drivers/net/ethernet/sun/sunvnet.c
@@ -913,6 +913,9 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
         if (unlikely(!skb))
                 goto out_dropped;
 
+        if (skb->len > port->rmtu)
+                goto out_dropped;
+
         spin_lock_irqsave(&port->vio.lock, flags);
 
         dr = &port->vio.drings[VIO_DRIVER_TX_RING];
@@ -944,7 +947,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
         skb = NULL;
 
         err = ldc_map_single(port->vio.lp, start, nlen,
-                             port->tx_bufs[txi].cookies, 2,
+                             port->tx_bufs[txi].cookies, VNET_MAXCOOKIES,
                              (LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_RW));
         if (err < 0) {
                 netdev_info(dev, "tx buffer map error %d\n", err);
@@ -1182,7 +1185,7 @@ static void vnet_set_rx_mode(struct net_device *dev)
 
 static int vnet_change_mtu(struct net_device *dev, int new_mtu)
 {
-        if (new_mtu != ETH_DATA_LEN)
+        if (new_mtu < 68 || new_mtu > 65535)
                 return -EINVAL;
 
         dev->mtu = new_mtu;
diff --git a/drivers/net/ethernet/sun/sunvnet.h b/drivers/net/ethernet/sun/sunvnet.h
index 02f507db9951..c91104542619 100644
--- a/drivers/net/ethernet/sun/sunvnet.h
+++ b/drivers/net/ethernet/sun/sunvnet.h
@@ -16,7 +16,7 @@
  */
 #define VNET_CLEAN_TIMEOUT              ((HZ/100)+1)
 
-#define VNET_MAXPACKET                  1518ULL /* ETH_FRAMELEN + VLAN_HDR */
+#define VNET_MAXPACKET                  (65535ULL + ETH_HLEN + VLAN_HLEN)
 #define VNET_TX_RING_SIZE               512
 #define VNET_TX_WAKEUP_THRESH(dr)       ((dr)->pending / 4)
 
@@ -26,10 +26,12 @@
  */
 #define VNET_PACKET_SKIP                6
 
+#define VNET_MAXCOOKIES                 (VNET_MAXPACKET/PAGE_SIZE + 1)
+
 struct vnet_tx_entry {
         struct sk_buff          *skb;
         unsigned int            ncookies;
-        struct ldc_trans_cookie cookies[2];
+        struct ldc_trans_cookie cookies[VNET_MAXCOOKIES];
 };
 
 struct vnet;