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Message-ID: <AANLkTimz3Mw5itChtTgHTeGT4seJauy3+FVrpEJn1iez@mail.gmail.com> Date: Thu, 13 Jan 2011 10:06:22 -0500 From: Jesse Gross <jesse@...ira.com> To: Matt Carlson <mcarlson@...adcom.com> Cc: Michael Leun <lkml20101129@...ton.leun.net>, Michael Chan <mchan@...adcom.com>, Eric Dumazet <eric.dumazet@...il.com>, David Miller <davem@...emloft.net>, Ben Greear <greearb@...delatech.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "netdev@...r.kernel.org" <netdev@...r.kernel.org> Subject: Re: [PATCH 2.6.36] vlan: Avoid hwaccel vlan packets when vid not used On Wed, Jan 12, 2011 at 8:21 PM, Matt Carlson <mcarlson@...adcom.com> wrote: > On Thu, Jan 06, 2011 at 08:36:27PM -0800, Jesse Gross wrote: >> On Thu, Jan 6, 2011 at 10:24 PM, Matt Carlson <mcarlson@...adcom.com> wrote: >> > On Sat, Dec 18, 2010 at 07:38:00PM -0800, Jesse Gross wrote: >> >> On Tue, Dec 14, 2010 at 11:16 PM, Michael Leun >> >> <lkml20101129@...ton.leun.net> wrote: >> >> > OK - all tests done on that DL320G5: >> >> > >> >> > For completeness, 2.6.37-rc5 unpatched: >> >> > >> >> > eth0, no vlan configured: totally broken - see double tagged vlans >> >> > without tag, single or untagged packets missing at all >> >> >> >> Random behavior? ?This one is somewhat hard to explain - maybe there >> >> are some other factors. ?eth0 has ASF on, so it always strips tags. ?I >> >> would expect it to behave like the vlan configured case. >> >> >> >> > >> >> > eth0, vlan configured: see packets without vlan tag (see double tagged >> >> > packets with one vlan tag) >> >> >> >> Both ASF and vlan group configured cause tag stripping to be enabled. >> >> Missing tag. >> >> >> >> > >> >> > eth1 same as originally reported: >> >> > without vlan configured see vlan tags (single and double tagged as >> >> > expected) >> >> >> >> No ASF and no vlan group means tag stripping is disabled. ?Have tag. >> >> >> >> > with vlan configured: see packets without vlan tag (see double tagged >> >> > packets with one vlan tag) >> >> >> >> Configuring vlan group causes stripping to be enabled. ?Missing tag. >> >> >> >> > >> >> > >> >> > 2.6.37-rc5, your tg3 use new vlan-code patch: >> >> > >> >> > eth0, no vlan configured: ?see packets without vlan tag (see double >> >> > tagged packets with one vlan tag) >> >> >> >> ASF enables tag stripping. ?Missing tag. >> >> >> >> > eth1, no vlan configured: see vlan tags (single and double tagged as >> >> > expected) >> >> >> >> No ASF, no vlan group means no stripping. ?Have tag. >> >> >> >> > >> >> > >> >> > eth0, vlan configured: as without vlan >> >> >> >> ASF enables stripping. ?Missing tag. >> >> >> >> > eth1, vlan configured: as without vlan >> >> >> >> With this patch vlan stripping is only enabled when ASF is on, so no >> >> stripping. ?Have tag. >> >> >> >> > >> >> > 2.6.37-rc5, your tg3 use new vlan-code patch with test patch ontop >> >> > >> >> > eth1 no vlan configured: see packets without vlan tag (see double tagged >> >> > packets with one vlan tag) >> >> >> >> With the second patch, vlan stripping is always enabled. ?Missing tag. >> >> >> >> > eth1 with vlan: the same >> >> >> >> Stripping still always enabled. ?Missing tag. >> >> >> >> The bottom line is whenever vlan stripping is enabled we're missing >> >> the outer tag. ?It might be worth adding some debugging in the area >> >> before napi_gro_receive/vlan_gro_receive (depending on version). ?My >> >> guess is that (desc->type_flags & RXD_FLAG_VLAN) is false even for >> >> vlan packets on this NIC. >> >> >> >> You said that everything works on the 5752? ?Matt, is it possible that >> >> the 5714 either has a problem with vlan stripping or a different way >> >> of reporting it? >> > >> > I don't think this is a 5714 specific issue. ?I think the problem is >> > rooted in the fact that the VLAN tag stripping is enabled. >> >> It's definitely related to vlan stripping being enabled. Other cards >> using tg3 seem to work fine with stripping though, which is why I >> thought it might be specific to the 5714. > > I just tested this on a 5714S, using a net-next-2.6 snapshot obtained > today. It does the right thing in both cases (2nd tg3 patch ommited / > applied). The tag is always visible in the packet stream as seen from > tcpdump. > >> > Your RXD_FLAG_VLAN idea sounds unlikely to me, but it's worth a check. >> > >> > The patch here is using __vlan_hwaccel_put_tag(), which informs the >> > stack a VLAN tag is present. ?If this is indeed a reporting problem, I'm >> > not sure what else the driver should be doing. >> >> The code to hand off the tag to the stack looks OK to me. Michael was >> seeing this on older versions of the kernel as well with this NIC, >> which predates both this patch and the larger vlan changes so it >> doesn't seem like a problem with passing the tag to the network stack. >> It's hard to know exactly what is going on though without seeing what >> the hardware is reporting. > > When RX_MODE_KEEP_VLAN_TAG is set, the RXD_FLAG_VLAN flag will not be set > when receiving a packet. The driver skips the __vlan_hwaccel_put_tag() > call. > > When RX_MODE_KEEP_VLAN_TAG is unset, the RXD_FLAG_VLAN flag is set, and > __vlan_hwaccel_put_tag() is called to reinject the packet. OK, thanks for testing it out. I'm not sure that there's anything more we can do without hearing from Michael. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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