ibmveth: Automatically enable larger rx buffer pools for larger mtu
Santiago Leon [Wed, 23 Jul 2008 18:34:23 +0000 (04:34 +1000)]
Activates larger rx buffer pools when the MTU is changed to a larger
value.  This patch de-activates the large rx buffer pools when the MTU
changes to a smaller value.

Signed-off-by: Santiago Leon <santil@us.ibm.com>
Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/net/ibmveth.c

index 0052780..007ca87 100644 (file)
@@ -1054,7 +1054,6 @@ static int ibmveth_change_mtu(struct net_device *dev, int new_mtu)
 {
        struct ibmveth_adapter *adapter = dev->priv;
        int new_mtu_oh = new_mtu + IBMVETH_BUFF_OH;
-       int reinit = 0;
        int i, rc;
 
        if (new_mtu < IBMVETH_MAX_MTU)
@@ -1067,15 +1066,21 @@ static int ibmveth_change_mtu(struct net_device *dev, int new_mtu)
        if (i == IbmVethNumBufferPools)
                return -EINVAL;
 
+       /* Deactivate all the buffer pools so that the next loop can activate
+          only the buffer pools necessary to hold the new MTU */
+       for (i = 0; i < IbmVethNumBufferPools; i++)
+               if (adapter->rx_buff_pool[i].active) {
+                       ibmveth_free_buffer_pool(adapter,
+                                                &adapter->rx_buff_pool[i]);
+                       adapter->rx_buff_pool[i].active = 0;
+               }
+
        /* Look for an active buffer pool that can hold the new MTU */
        for(i = 0; i<IbmVethNumBufferPools; i++) {
-               if (!adapter->rx_buff_pool[i].active) {
-                       adapter->rx_buff_pool[i].active = 1;
-                       reinit = 1;
-               }
+               adapter->rx_buff_pool[i].active = 1;
 
                if (new_mtu_oh < adapter->rx_buff_pool[i].buff_size) {
-                       if (reinit && netif_running(adapter->netdev)) {
+                       if (netif_running(adapter->netdev)) {
                                adapter->pool_config = 1;
                                ibmveth_close(adapter->netdev);
                                adapter->pool_config = 0;
@@ -1402,14 +1407,15 @@ const char * buf, size_t count)
                                return -EPERM;
                        }
 
-                       pool->active = 0;
                        if (netif_running(netdev)) {
                                adapter->pool_config = 1;
                                ibmveth_close(netdev);
+                               pool->active = 0;
                                adapter->pool_config = 0;
                                if ((rc = ibmveth_open(netdev)))
                                        return rc;
                        }
+                       pool->active = 0;
                }
        } else if (attr == &veth_num_attr) {
                if (value <= 0 || value > IBMVETH_MAX_POOL_COUNT)