e1000: remove races when changing mtu (3d6114e7) · Commits · 戴 / test

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 <jesse.brandeburg@intel.com> Signed-off-by:

Don Skidmore <donald.c.skidmore@intel.com> Signed-off-by:

Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/e1000/e1000_main.c

+14 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

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