ibmveth: Automatically enable larger rx buffer pools for larger mtu

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>

1 files changed, 13 insertions, 7 deletions

diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c
index 00527805e4f1..007ca8735a94 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -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)