[PATCH 2.6.12.1 6/12] S2io: Support for runtime MTU change

[raghavendra.koushik@xxxxxxxxxxxx]

Hi,
Patch below supports MTU change on-the-fly(without bringing interface
down)

Signed-off-by: Ravinandan Arakali <ravinandan.arakali@xxxxxxxxxxxx>
Signed-off-by: Raghavendra Koushik <raghavendra.koushik@xxxxxxxxxxxx>
---
diff -uprN vanilla_kernel/drivers/net/s2io.c linux-2.6.12-rc6/drivers/net/s2io.c
--- vanilla_kernel/drivers/net/s2io.c   2005-06-28 02:04:52.000000000 -0700
+++ linux-2.6.12-rc6/drivers/net/s2io.c 2005-06-28 02:07:26.000000000 -0700
@@ -2850,6 +2850,7 @@ int s2io_xmit(struct sk_buff *skb, struc
        }
 
        txdp->Control_2 |= config->tx_intr_type;
+
        txdp->Control_1 |= (TXD_BUFFER0_SIZE(frg_len) |
                            TXD_GATHER_CODE_FIRST);
        txdp->Control_1 |= TXD_LIST_OWN_XENA;
@@ -4247,14 +4248,6 @@ int s2io_ioctl(struct net_device *dev, s
 int s2io_change_mtu(struct net_device *dev, int new_mtu)
 {
        nic_t *sp = dev->priv;
-       XENA_dev_config_t __iomem *bar0 = sp->bar0;
-       register u64 val64;
-
-       if (netif_running(dev)) {
-               DBG_PRINT(ERR_DBG, "%s: Must be stopped to ", dev->name);
-               DBG_PRINT(ERR_DBG, "change its MTU\n");
-               return -EBUSY;
-       }
 
        if ((new_mtu < MIN_MTU) || (new_mtu > S2IO_JUMBO_SIZE)) {
                DBG_PRINT(ERR_DBG, "%s: MTU size is invalid.\n",
@@ -4262,11 +4255,22 @@ int s2io_change_mtu(struct net_device *d
                return -EPERM;
        }
 
-       /* Set the new MTU into the PYLD register of the NIC */
-       val64 = new_mtu;
-       writeq(vBIT(val64, 2, 14), &bar0->rmac_max_pyld_len);
-
        dev->mtu = new_mtu;
+       if (netif_running(dev)) {
+               s2io_card_down(sp);
+               netif_stop_queue(dev);
+               if (s2io_card_up(sp)) {
+                       DBG_PRINT(ERR_DBG, "%s: Device bring up failed\n",
+                                 __FUNCTION__);
+               }
+               if (netif_queue_stopped(dev))
+                       netif_wake_queue(dev);
+       } else { /* Device is down */
+               XENA_dev_config_t __iomem *bar0 = sp->bar0;
+               u64 val64 = new_mtu;
+
+               writeq(vBIT(val64, 2, 14), &bar0->rmac_max_pyld_len);
+       }
 
        return 0;
 }