> -----Original Message----- > From: Daniel Axtens [mailto:d...@axtens.net] > Sent: Wednesday, January 31, 2018 8:46 AM > To: netdev@vger.kernel.org > Cc: Daniel Axtens <d...@axtens.net>; Eric Dumazet <eric.duma...@gmail.com>; > Chopra, Manish <manish.cho...@cavium.com>; Jason Wang > <jasow...@redhat.com>; Pravin Shelar <pshe...@ovn.org>; Marcelo Ricardo > Leitner <marcelo.leit...@gmail.com> > Subject: [PATCH v4 2/2] bnx2x: disable GSO where gso_size is too big for > hardware > > If a bnx2x card is passed a GSO packet with a gso_size larger than > ~9700 bytes, it will cause a firmware error that will bring the card > down: > > bnx2x: [bnx2x_attn_int_deasserted3:4323(enP24p1s0f0)]MC assert! > bnx2x: [bnx2x_mc_assert:720(enP24p1s0f0)]XSTORM_ASSERT_LIST_INDEX 0x2 > bnx2x: [bnx2x_mc_assert:736(enP24p1s0f0)]XSTORM_ASSERT_INDEX 0x0 = > 0x00000000 0x25e43e47 0x00463e01 0x00010052 > bnx2x: [bnx2x_mc_assert:750(enP24p1s0f0)]Chip Revision: everest3, FW > Version: 7_13_1 ... (dump of values continues) ... > > Detect when the mac length of a GSO packet is greater than the maximum > packet size (9700 bytes) and disable GSO. > > Signed-off-by: Daniel Axtens <d...@axtens.net> > > --- > > v4: Only call the slow check if the gso_size is large. > Eric - I think this is what you had in mind? > Manish - do you think this is an acceptable performance trade-off? > GSO will work for any packet size, and only jumbo frames will > have to do the slower test. > > Again, only build-tested. > --- > drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 18 > ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c > b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c > index 7b08323e3f3d..74fc9af4aadb 100644 > --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c > +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c > @@ -12934,6 +12934,24 @@ static netdev_features_t > bnx2x_features_check(struct sk_buff *skb, > struct net_device *dev, > netdev_features_t features) > { > + /* > + * A skb with gso_size + header length > 9700 will cause a > + * firmware panic. Drop GSO support. > + * > + * Eventually the upper layer should not pass these packets down. > + * > + * For speed, if the gso_size is <= 9000, assume there will > + * not be 700 bytes of headers and pass it through. Only do a > + * full (slow) validation if the gso_size is > 9000. > + * > + * (Due to the way SKB_BY_FRAGS works this will also do a full > + * validation in that case.) > + */ > + if (unlikely(skb_is_gso(skb) && > + (skb_shinfo(skb)->gso_size > 9000) && > + !skb_gso_validate_mac_len(skb, 9700))) > + features &= ~NETIF_F_GSO_MASK;
Hi Daniel, Obviously, it could be bad from performance perspective since every gso packet has to do these check. When running iperf/netperf performance benchmark, where GSO is likely to occur. Why do you have to put two checks for skb_is_gso() and gso_size ? Isn't gso_size > anything means GSO skb ? I assume it won't cause disabling the offload if "headers [L2 + L3 + L4] + gso_size" is still <= 9700. ? Thanks, Manish
