[PATCH] S2io: Support for runtime MTU change

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

Signed-off-by: Ravinandan Arakali <ravinandan.arakali@neterion.com>
Signed-off-by: Raghavendra Koushik <raghavendra.koushik@neterion.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 16 insertions, 12 deletions

diff --git a/drivers/net/s2io.c b/drivers/net/s2io.c
index 28d6d3746c80..aff1fb74e14b 100644
--- a/drivers/net/s2io.c
+++ b/drivers/net/s2io.c
@@ -2849,6 +2849,7 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
         }
 
         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;
@@ -4246,14 +4247,6 @@ int s2io_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 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",
@@ -4261,11 +4254,22 @@ int s2io_change_mtu(struct net_device *dev, int new_mtu)
                 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;
 }