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author | Petr Tesarik <ptesarik@suse.cz> | 2008-11-21 16:42:58 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2008-11-21 16:42:58 -0800 |
commit | 33cf71cee14743185305c61625c4544885055733 (patch) | |
tree | d05c9fb2fd12d8eede22c261c2db57d30f96a73a /drivers/net/ixgbe | |
parent | 38ae07e44bb2dc86770555a1acafcb937ec74478 (diff) | |
download | op-kernel-dev-33cf71cee14743185305c61625c4544885055733.zip op-kernel-dev-33cf71cee14743185305c61625c4544885055733.tar.gz |
tcp: Do not use TSO/GSO when there is urgent data
This patch fixes http://bugzilla.kernel.org/show_bug.cgi?id=12014
Since most (if not all) implementations of TSO and even the in-kernel
software GSO do not update the urgent pointer when splitting a large
segment, it is necessary to turn off TSO/GSO for all outgoing traffic
with the URG pointer set.
Looking at tcp_current_mss (and the preceding comment) I even think
this was the original intention. However, this approach is insufficient,
because TSO/GSO is turned off only for newly created frames, not for
frames which were already pending at the arrival of a message with
MSG_OOB set. These frames were created when TSO/GSO was enabled,
so they may be large, and they will have the urgent pointer set
in tcp_transmit_skb().
With this patch, such large packets will be fragmented again before
going to the transmit routine.
As a side note, at least the following NICs are known to screw up
the urgent pointer in the TCP header when doing TSO:
Intel 82566MM (PCI ID 8086:1049)
Intel 82566DC (PCI ID 8086:104b)
Intel 82541GI (PCI ID 8086:1076)
Broadcom NetXtreme II BCM5708 (PCI ID 14e4:164c)
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ixgbe')
0 files changed, 0 insertions, 0 deletions