[PATCH 5.19 057/365] mptcp, btf: Add struct mptcp_sock definition when CONFIG_MPTCP is disabled

[Greg Kroah-Hartman]

From: Jiri Olsa <jolsa@xxxxxxxxxx>

commit f1d41f7720c89705c20e4335a807b1c518c2e7be upstream.

The btf_sock_ids array needs struct mptcp_sock BTF ID for the
bpf_skc_to_mptcp_sock helper.

When CONFIG_MPTCP is disabled, the 'struct mptcp_sock' is not
defined and resolve_btfids will complain with:

  [...]
  BTFIDS  vmlinux
  WARN: resolve_btfids: unresolved symbol mptcp_sock
  [...]

Add an empty definition for struct mptcp_sock when CONFIG_MPTCP
is disabled.

Fixes: 3bc253c2e652 ("bpf: Add bpf_skc_to_mptcp_sock_proto")
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Reviewed-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
Link: https://lore.kernel.org/bpf/20220802163324.1873044-1-jolsa@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 include/net/mptcp.h |    4 ++++
 1 file changed, 4 insertions(+)

--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -290,4 +290,8 @@ struct mptcp_sock *bpf_mptcp_sock_from_s
 static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
 #endif
 
+#if !IS_ENABLED(CONFIG_MPTCP)
+struct mptcp_sock { };
+#endif
+
 #endif /* __NET_MPTCP_H */