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

Alexei Starovoitov says:

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pull-request: bpf 2018-12-18

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

The main changes are:

1) promote bpf_perf_event.h to mandatory UAPI header, from Masahiro.
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Signed-off-by: David S. Miller <davem@davemloft.net>