Merge branch 'sock_map: fix ->poll() and update selftests'

Cong Wang says:

====================
This patchset fixes ->poll() for sockets in sockmap and updates
selftests accordingly with select(). Please check each patch
for more details.

Fixes: c50524ec ("Merge branch 'sockmap: add sockmap support for unix datagram socket'")
Fixes: 89d69c5d

 ("Merge branch 'sockmap: introduce BPF_SK_SKB_VERDICT and support UDP'")
Acked-by: John Fastabend <john.fastabend@gmail.com>

---
v4: add a comment in udp_poll()

v3: drop sk_psock_get_checked()
    reuse tcp_bpf_sock_is_readable()

v2: rename and reuse ->stream_memory_read()
    fix a compile error in sk_psock_get_checked()

Cong Wang (3):
  net: rename ->stream_memory_read to ->sock_is_readable
  skmsg: extract and reuse sk_msg_is_readable()
  net: implement ->sock_is_readable() for UDP and AF_UNIX

====================

Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>