> From: Intel-wired-lan [mailto:intel-wired-lan-boun...@lists.osuosl.org] On > Behalf Of Alexander Duyck > Sent: Wednesday, April 08, 2015 2:03 PM > To: intel-wired-...@lists.osuosl.org; Kirsher, Jeffrey T > Cc: netdev@vger.kernel.org; m...@cchtml.com; ht...@twofifty.com > Subject: [Intel-wired-lan] [PATCH] e1000e: Cleanup handling of VLAN_HLEN > as a part of max frame size > > When the VLAN_HLEN was added to the calculation for the maximum frame size > there seems to have been a number of issues added to the driver. > > The first issue is that in some cases the maximum frame size for a device > never really reached the actual maximum frame size as the VLAN header > length was not included the calculation for that value. As a result some > parts only supported a maximum frame size of either 1496 in the case of > parts that didn't support jumbo frames, and 8996 in the case of the parts > that do. > > The second issue is the fact that there were several checks that weren't > updated so as a result setting an MTU of 1500 was treated as enabling > jumbo > frames as the calculated value was 1522 instead of 1518. I have addressed > those by replacing ETH_FRAME_LEN with VLAN_ETH_FRAME_LEN where > appropriate. > > The final issue was the fact that lowering the MTU below 1500 would cause > the driver to allocate 2K buffers for the rings. This is an old issue > that > was fixed several years ago in igb/ixgbe and I am addressing now by just > replacing == with a <= so that we always just round up to 1522 for > anything > that isn't a jumbo frame. > > Fixes: c751a3d58cf2d ("e1000e: Correctly include VLAN_HLEN when changing > interface MTU") > Signed-off-by: Alexander Duyck <alexander.h.du...@redhat.com> > --- > > I have only build tested this though I am 99% sure the fixes here are > correct. This patch should fix issues on 82573 and ich8 w/ setting an MTU > of 1500, and for the PCH series w/ setting an MTU of 9000. > > I assume I can get away with bumping the max_hw_frame_size for the PCH > parts from 9018 to 9022 based on the fact that the Windows INF for the > parts > lists supporting either 1514, 4088, and 9014 all of which exclude the 8 > bytes for CRC and VLAN header. > > drivers/net/ethernet/intel/e1000e/82571.c | 2 +- > drivers/net/ethernet/intel/e1000e/ich8lan.c | 10 +++++----- > drivers/net/ethernet/intel/e1000e/netdev.c | 18 ++++++++---------- > 3 files changed, 14 insertions(+), 16 deletions(-)
Tested-by: Aaron Brown <aaron.f.br...@intel.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
