user/sven/linux.git/include/linux/netdevice.h, branch v4.10.16

net: solve a NAPI race

2017-03-30T07:44:02Z

commit 39e6c8208d7b6fb9d2047850fb3327db567b564b upstream. While playing with mlx4 hardware timestamping of RX packets, I found that some packets were received by TCP stack with a ~200 ms delay... Since the timestamp was provided by the NIC, and my probe was added in tcp_v4_rcv() while in BH handler, I was confident it was not a sender issue, or a drop in the network. This would happen with a very low probability, but hurting RPC workloads. A NAPI driver normally arms the IRQ after the napi_complete_done(), after NAPI_STATE_SCHED is cleared, so that the hard irq handler can grab it. Problem is that if another point in the stack grabs NAPI_STATE_SCHED bit while IRQ are not disabled, we might have later an IRQ firing and finding this bit set, right before napi_complete_done() clears it. This can happen with busy polling users, or if gro_flush_timeout is used. But some other uses of napi_schedule() in drivers can cause this as well. thread 1 thread 2 (could be on same cpu, or not) // busy polling or napi_watchdog() napi_schedule(); ... napi->poll() device polling: read 2 packets from ring buffer Additional 3rd packet is available. device hard irq // does nothing because NAPI_STATE_SCHED bit is owned by thread 1 napi_schedule(); napi_complete_done(napi, 2); rearm_irq(); Note that rearm_irq() will not force the device to send an additional IRQ for the packet it already signaled (3rd packet in my example) This patch adds a new NAPI_STATE_MISSED bit, that napi_schedule_prep() can set if it could not grab NAPI_STATE_SCHED Then napi_complete_done() properly reschedules the napi to make sure we do not miss something. Since we manipulate multiple bits at once, use cmpxchg() like in sk_busy_loop() to provide proper transactions. In v2, I changed napi_watchdog() to use a relaxed variant of napi_schedule_prep() : No need to set NAPI_STATE_MISSED from this point. In v3, I added more details in the changelog and clears NAPI_STATE_MISSED in busy_poll_stop() In v4, I added the ideas given by Alexander Duyck in v3 review Signed-off-by: Eric Dumazet Cc: Alexander Duyck Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: introduce device min_header_len

2017-02-08T18:56:37Z

The stack must not pass packets to device drivers that are shorter than the minimum link layer header length. Previously, packet sockets would drop packets smaller than or equal to dev->hard_header_len, but this has false positives. Zero length payload is used over Ethernet. Other link layer protocols support variable length headers. Support for validation of these protocols removed the min length check for all protocols. Introduce an explicit dev->min_header_len parameter and drop all packets below this value. Initially, set it to non-zero only for Ethernet and loopback. Other protocols can follow in a patch to net-next. Fixes: 9ed988cd5915 ("packet: validate variable length ll headers") Reported-by: Sowmini Varadhan Signed-off-by: Willem de Bruijn Acked-by: Eric Dumazet Acked-by: Sowmini Varadhan Signed-off-by: David S. Miller

net: fix ndo_features_check/ndo_fix_features comment ordering

2017-02-01T17:10:56Z

Commit cdba756f5803a2 ("net: move ndo_features_check() close to ndo_start_xmit()") inadvertently moved the doc comment for .ndo_fix_features instead of .ndo_features_check. Fix the comment ordering. Fixes: cdba756f5803a2 ("net: move ndo_features_check() close to ndo_start_xmit()") Signed-off-by: Dimitris Michailidis Acked-by: Eric Dumazet Signed-off-by: David S. Miller

gro: Disable frag0 optimization on IPv6 ext headers

2017-01-11T02:30:33Z

The GRO fast path caches the frag0 address. This address becomes invalid if frag0 is modified by pskb_may_pull or its variants. So whenever that happens we must disable the frag0 optimization. This is usually done through the combination of gro_header_hard and gro_header_slow, however, the IPv6 extension header path did the pulling directly and would continue to use the GRO fast path incorrectly. This patch fixes it by disabling the fast path when we enter the IPv6 extension header path. Fixes: 78a478d0efd9 ("gro: Inline skb_gro_header and cache frag0 virtual address") Reported-by: Slava Shwartsman Signed-off-by: Herbert Xu Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: rfs: add a jump label

2016-12-08T18:18:35Z

RFS is not commonly used, so add a jump label to avoid some conditionals in fast path. Signed-off-by: Eric Dumazet Cc: Paolo Abeni Signed-off-by: David S. Miller

net/sched: cls_flower: Add offload support using egress Hardware device

2016-12-02T18:28:37Z

In order to support hardware offloading when the device given by the tc rule is different from the Hardware underline device, extract the mirred (egress) device from the tc action when a filter is added, using the new tc_action_ops, get_dev(). Flower caches the information about the mirred device and use it for calling ndo_setup_tc in filter change, update stats and delete. Calling ndo_setup_tc of the mirred (egress) device instead of the ingress device will allow a resolution between the software ingress device and the underline hardware device. The resolution will take place inside the offloading driver using 'egress_device' flag added to tc_to_netdev struct which is provided to the offloading driver. Signed-off-by: Hadar Hen Zion Acked-by: Jiri Pirko Signed-off-by: David S. Miller

bpf, xdp: allow to pass flags to dev_change_xdp_fd

2016-11-30T15:27:20Z

Add an IFLA_XDP_FLAGS attribute that can be passed for setting up XDP along with IFLA_XDP_FD, which eventually allows user space to implement typical add/replace/delete logic for programs. Right now, calling into dev_change_xdp_fd() will always replace previous programs. When passed XDP_FLAGS_UPDATE_IF_NOEXIST, we can handle this more graceful when requested by returning -EBUSY in case we try to attach a new program, but we find that another one is already attached. This will be used by upcoming front-end for iproute2 as well. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

netdevice: fix sparse warning for HARD_TX_LOCK

2016-11-27T20:28:35Z

sparse warns about context imbalance in any code that uses HARD_TX_LOCK/UNLOCK - this is because it's unable to determine that flags don't change so lock and unlock are paired. Seems easy enough to fix by adding __acquire/__release calls. With this patch af_packet.c is now sparse-clean, Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2016-11-27T04:42:21Z

udplite conflict is resolved by taking what 'net-next' did which removed the backlog receive method assignment, since it is no longer necessary. Two entries were added to the non-priv ethtool operations switch statement, one in 'net' and one in 'net-next, so simple overlapping changes. Signed-off-by: David S. Miller

net: Add net-device param to the get offloaded stats ndo

2016-11-24T21:01:14Z

Some drivers would need to check few internal matters for that. To be used in downstream mlx5 commit. Signed-off-by: Or Gerlitz Signed-off-by: Saeed Mahameed Signed-off-by: David S. Miller