From: Scott Moser <smoser@redhat.com> Date: Tue, 23 Oct 2007 15:56:59 -0400 Subject: [net] ibmveth: enable large rx buf pool for large mtu Message-id: 11931694203521-do-send-email-smoser@redhat.com O-Subject: [PATCH RHEL5u2] bz250827 Jumbo frames cannot be enabled on ibmveth [3/3] Bugzilla: 250827 Description: ----------- Jumbo frames cannot be enabled on ibmveth. For example, adding MTU=9000 to /etc/sysconfig/network-scripts/ifcfg-eth1 does not work since receive buffer pools are not getting allocated. When attempting to use the ibmveth sysfs interface to allocate the buffer pools prior to activating the interface, an oops resulted. Currently (2.6.18-52.el5), with inf=eth1 and mtu=9000 : - ip link set dev $inf mtu $mtu fails with: SIOCSIFMTU: Invalid argument - echo 1 > /sys/bus/vio/devices/30000004/pool3/active and echo 65536 > /sys/class/net/$i/device/pool0/size drops into xmon The patch below fixes the listed crashes above and makes 'ip' able to set the mtu as it should. commit ce6eea58eb8f50f563663c6e723b4bbbe55b012e Author: Brian King <brking@linux.vnet.ibm.com> Date: Fri Jun 8 14:05:17 2007 -0500 ibmveth: Automatically enable larger rx buffer pools for larger mtu Currently, ibmveth maintains several rx buffer pools, which can be modified through sysfs. By default, pools are not allocated by default such that jumbo frames cannot be supported without first activating larger rx buffer pools. This results in failures when attempting to change the mtu. This patch makes ibmveth automatically allocate these larger buffer pools when the mtu is changed. Signed-off-by: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org> --- drivers/net/ibmveth.c | 27 +++++++++++++++++++++++---- 1 files changed, 23 insertions(+), 4 deletions(-) diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c index 3d72317..a6e864e 100644 --- a/drivers/net/ibmveth.c +++ b/drivers/net/ibmveth.c @@ -916,17 +916,36 @@ 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 i; + int reinit = 0; + int i, rc; if (new_mtu < IBMVETH_MAX_MTU) return -EINVAL; + for (i = 0; i < IbmVethNumBufferPools; i++) + if (new_mtu_oh < adapter->rx_buff_pool[i].buff_size) + break; + + if (i == IbmVethNumBufferPools) + return -EINVAL; + /* 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) - continue; + if (!adapter->rx_buff_pool[i].active) { + adapter->rx_buff_pool[i].active = 1; + reinit = 1; + } + if (new_mtu_oh < adapter->rx_buff_pool[i].buff_size) { - dev->mtu = new_mtu; + if (reinit && netif_running(adapter->netdev)) { + adapter->pool_config = 1; + ibmveth_close(adapter->netdev); + adapter->pool_config = 0; + dev->mtu = new_mtu; + if ((rc = ibmveth_open(adapter->netdev))) + return rc; + } else + dev->mtu = new_mtu; return 0; } } -- 1.5.3.5.645.gbb47