[PATCH bpf-next] mptcp: Add struct mptcp_sock definition when CONFIG_MPTCP is disabled

[Jiri Olsa <jolsa@xxxxxxxxxx>]

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

Adding empty difinition for struct mptcp_sock when CONFIG_MPTCP
is disabled.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 include/net/mptcp.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index ac9cf7271d46..25741a52c666 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -59,6 +59,10 @@ struct mptcp_addr_info {
 	};
 };
 
+#if !IS_ENABLED(CONFIG_MPTCP)
+struct mptcp_sock { };
+#endif
+
 struct mptcp_out_options {
 #if IS_ENABLED(CONFIG_MPTCP)
 	u16 suboptions;
-- 
2.35.3