[net-2.6 PATCH 08/13] e1000: remove races when changing mtu
From: Jeff Kirsher <hidden>
Date: 2009-09-25 22:19:18
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Jesse Brandeburg <redacted> 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 <redacted> Signed-off-by: Don Skidmore <redacted> Signed-off-by: Jeff Kirsher <redacted> --- drivers/net/e1000/e1000_main.c | 16 ++++++++++++++-- 1 files 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; }