This is a note to let you know that I've just added the patch titled i40e: Be much more verbose about what we can and cannot offload to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: i40e-be-much-more-verbose-about-what-we-can-and-cannot-offload.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From f114dca2533ca770aebebffb5ed56e5e7d1fb3fb Mon Sep 17 00:00:00 2001 From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> Date: Tue, 25 Oct 2016 16:08:46 -0700 Subject: i40e: Be much more verbose about what we can and cannot offload From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> commit f114dca2533ca770aebebffb5ed56e5e7d1fb3fb upstream. This change makes it so that we are much more robust about defining what we can and cannot offload. Previously we were just checking for the L4 tunnel header length, however there are other fields we should be verifying as there are multiple scenarios in which we cannot perform hardware offloads. In addition the device only supports GSO as long as the MSS is 64 or greater. We were not checking this so an MSS less than that was resulting in Tx hangs. Change-ID: I5e2fd5f3075c73601b4b36327b771c64fcb6c31b Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> Tested-by: Andrew Bowers <andrewx.bowers@xxxxxxxxx> Cc: Philipp Hahn <hahn@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/intel/i40e/i40e_main.c | 52 +++++++++++++++++++++++----- 1 file changed, 44 insertions(+), 8 deletions(-) --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -9059,10 +9059,6 @@ static int i40e_ndo_bridge_getlink(struc 0, 0, nlflags, filter_mask, NULL); } -/* Hardware supports L4 tunnel length of 128B (=2^7) which includes - * inner mac plus all inner ethertypes. - */ -#define I40E_MAX_TUNNEL_HDR_LEN 128 /** * i40e_features_check - Validate encapsulated packet conforms to limits * @skb: skb buff @@ -9073,12 +9069,52 @@ static netdev_features_t i40e_features_c struct net_device *dev, netdev_features_t features) { - if (skb->encapsulation && - ((skb_inner_network_header(skb) - skb_transport_header(skb)) > - I40E_MAX_TUNNEL_HDR_LEN)) - return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK); + size_t len; + + /* No point in doing any of this if neither checksum nor GSO are + * being requested for this frame. We can rule out both by just + * checking for CHECKSUM_PARTIAL + */ + if (skb->ip_summed != CHECKSUM_PARTIAL) + return features; + + /* We cannot support GSO if the MSS is going to be less than + * 64 bytes. If it is then we need to drop support for GSO. + */ + if (skb_is_gso(skb) && (skb_shinfo(skb)->gso_size < 64)) + features &= ~NETIF_F_GSO_MASK; + + /* MACLEN can support at most 63 words */ + len = skb_network_header(skb) - skb->data; + if (len & ~(63 * 2)) + goto out_err; + + /* IPLEN and EIPLEN can support at most 127 dwords */ + len = skb_transport_header(skb) - skb_network_header(skb); + if (len & ~(127 * 4)) + goto out_err; + + if (skb->encapsulation) { + /* L4TUNLEN can support 127 words */ + len = skb_inner_network_header(skb) - skb_transport_header(skb); + if (len & ~(127 * 2)) + goto out_err; + + /* IPLEN can support at most 127 dwords */ + len = skb_inner_transport_header(skb) - + skb_inner_network_header(skb); + if (len & ~(127 * 4)) + goto out_err; + } + + /* No need to validate L4LEN as TCP is the only protocol with a + * a flexible value and we support all possible values supported + * by TCP, which is at most 15 dwords + */ return features; +out_err: + return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK); } static const struct net_device_ops i40e_netdev_ops = { Patches currently in stable-queue which might be from alexander.h.duyck@xxxxxxxxx are queue-4.9/i40e-be-much-more-verbose-about-what-we-can-and-cannot-offload.patch