Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2019-03-04

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Add AF_XDP support to libbpf. Rationale is to facilitate writing
   AF_XDP applications by offering higher-level APIs that hide many
   of the details of the AF_XDP uapi. Sample programs are converted
   over to this new interface as well, from Magnus.

2) Introduce a new cant_sleep() macro for annotation of functions
   that cannot sleep and use it in BPF_PROG_RUN() to assert that
   BPF programs run under preemption disabled context, from Peter.

3) Introduce per BPF prog stats in order to monitor the usage
   of BPF; this is controlled by kernel.bpf_stats_enabled sysctl
   knob where monitoring tools can make use of this to efficiently
   determine the average cost of programs, from Alexei.

4) Split up BPF selftest's test_progs similarly as we already
   did with test_verifier. This allows to further reduce merge
   conflicts in future and to get more structure into our
   quickly growing BPF selftest suite, from Stanislav.

5) Fix a bug in BTF's dedup algorithm which can cause an infinite
   loop in some circumstances; also various BPF doc fixes and
   improvements, from Andrii.

6) Various BPF sample cleanups and migration to libbpf in order
   to further isolate the old sample loader code (so we can get
   rid of it at some point), from Jakub.

7) Add a new BPF helper for BPF cgroup skb progs that allows
   to set ECN CE code point and a Host Bandwidth Manager (HBM)
   sample program for limiting the bandwidth used by v2 cgroups,
   from Lawrence.

8) Enable write access to skb->queue_mapping from tc BPF egress
   programs in order to let BPF pick TX queue, from Jesper.

9) Fix a bug in BPF spinlock handling for map-in-map which did
   not propagate spin_lock_off to the meta map, from Yonghong.

10) Fix a bug in the new per-CPU BPF prog counters to properly
    initialize stats for each CPU, from Eric.

11) Add various BPF helper prototypes to selftest's bpf_helpers.h,
    from Willem.

12) Fix various BPF samples bugs in XDP and tracing progs,
    from Toke, Daniel and Yonghong.

13) Silence preemption splat in test_bpf after BPF_PROG_RUN()
    enforces it now everywhere, from Anders.

14) Fix a signedness bug in libbpf's btf_dedup_ref_type() to
    get error handling working, from Dan.

15) Fix bpftool documentation and auto-completion with regards
    to stream_{verdict,parser} attach types, from Alban.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 36 insertions, 2 deletions

diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst
index 4ae4f9d8f8fe..e14d7d40fc75 100644
--- a/Documentation/networking/af_xdp.rst
+++ b/Documentation/networking/af_xdp.rst
@@ -295,6 +295,41 @@ using::
 For XDP_SKB mode, use the switch "-S" instead of "-N" and all options
 can be displayed with "-h", as usual.
 
+FAQ
+=======
+
+Q: I am not seeing any traffic on the socket. What am I doing wrong?
+
+A: When a netdev of a physical NIC is initialized, Linux usually
+   allocates one Rx and Tx queue pair per core. So on a 8 core system,
+   queue ids 0 to 7 will be allocated, one per core. In the AF_XDP
+   bind call or the xsk_socket__create libbpf function call, you
+   specify a specific queue id to bind to and it is only the traffic
+   towards that queue you are going to get on you socket. So in the
+   example above, if you bind to queue 0, you are NOT going to get any
+   traffic that is distributed to queues 1 through 7. If you are
+   lucky, you will see the traffic, but usually it will end up on one
+   of the queues you have not bound to.
+
+   There are a number of ways to solve the problem of getting the
+   traffic you want to the queue id you bound to. If you want to see
+   all the traffic, you can force the netdev to only have 1 queue, queue
+   id 0, and then bind to queue 0. You can use ethtool to do this::
+
+   sudo ethtool -L <interface> combined 1
+
+   If you want to only see part of the traffic, you can program the
+   NIC through ethtool to filter out your traffic to a single queue id
+   that you can bind your XDP socket to. Here is one example in which
+   UDP traffic to and from port 4242 are sent to queue 2::
+
+   sudo ethtool -N <interface> rx-flow-hash udp4 fn
+   sudo ethtool -N <interface> flow-type udp4 src-port 4242 dst-port \
+   4242 action 2
+
+   A number of other ways are possible all up to the capabilitites of
+   the NIC you have.
+
 Credits
 =======
 
@@ -309,4 +344,3 @@ Credits
 - Michael S. Tsirkin
 - Qi Z Zhang
 - Willem de Bruijn
-
diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt
index b5e060edfc38..319e5e041f38 100644
--- a/Documentation/networking/filter.txt
+++ b/Documentation/networking/filter.txt
@@ -829,7 +829,7 @@ tracing filters may do to maintain counters of events, for example. Register R9
 is not used by socket filters either, but more complex filters may be running
 out of registers and would have to resort to spill/fill to stack.
 
-Internal BPF can used as generic assembler for last step performance
+Internal BPF can be used as a generic assembler for last step performance
 optimizations, socket filters and seccomp are using it as assembler. Tracing
 filters may use it as assembler to generate code from kernel. In kernel usage
 may not be bounded by security considerations, since generated internal BPF code