From 3d6114e71dffb9fb9dedc8569103310c5bbf0296 Mon Sep 17 00:00:00 2001 From: Jesse Brandeburg Date: Fri, 25 Sep 2009 12:19:02 +0000 Subject: [PATCH] e1000: remove races when changing mtu this patch fixes a bug that occurs when routing packets and simultaneously changing the mtu. the rx_buffer_len variable is used during the rx cleanup and if that changes on the fly without stopping traffic bad things happen Signed-off-by: Jesse Brandeburg Signed-off-by: Don Skidmore Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/e1000/e1000_main.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c index cdbf4fb..2178e0d 100644 --- a/drivers/net/e1000/e1000_main.c +++ b/drivers/net/e1000/e1000_main.c @@ -3141,6 +3141,13 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu) break; } + while (test_and_set_bit(__E1000_RESETTING, &adapter->flags)) + msleep(1); + /* e1000_down has a dependency on max_frame_size */ + hw->max_frame_size = max_frame; + if (netif_running(netdev)) + e1000_down(adapter); + /* NOTE: netdev_alloc_skb reserves 16 bytes, and typically NET_IP_ALIGN * means we reserve 2 more, this pushes us to allocate from the next * larger slab size. @@ -3169,11 +3176,16 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu) (max_frame == MAXIMUM_ETHERNET_VLAN_SIZE))) adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE; + printk(KERN_INFO "e1000: %s changing MTU from %d to %d\n", + netdev->name, netdev->mtu, new_mtu); netdev->mtu = new_mtu; - hw->max_frame_size = max_frame; if (netif_running(netdev)) - e1000_reinit_locked(adapter); + e1000_up(adapter); + else + e1000_reset(adapter); + + clear_bit(__E1000_RESETTING, &adapter->flags); return 0; } -- 2.7.4