This patch adds a subflow pointers array in struct mptcp_sched_data. Set
the array before invoking get_subflow(), then get it in get_subflow() in
the BPF contexts.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 include/net/mptcp.h                           |  3 +++
 net/mptcp/sched.c                             | 15 +++++++++++++++
 tools/testing/selftests/bpf/bpf_tcp_helpers.h |  8 ++++++++
 3 files changed, 26 insertions(+)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index b596ba7a8494..d48c66de8466 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -96,10 +96,13 @@ struct mptcp_out_options {
 };
 
 #define MPTCP_SCHED_NAME_MAX	16
+#define MPTCP_SUBFLOWS_MAX	8
 
 struct mptcp_sched_data {
 	struct sock	*sock;
 	bool		call_again;
+	u8		subflows;
+	struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
 };
 
 struct mptcp_sched_ops {
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
index 3ceb721e6489..f86b97292044 100644
--- a/net/mptcp/sched.c
+++ b/net/mptcp/sched.c
@@ -91,9 +91,24 @@ void mptcp_release_sched(struct mptcp_sock *msk)
 static int mptcp_sched_data_init(struct mptcp_sock *msk,
 				 struct mptcp_sched_data *data)
 {
+	struct mptcp_subflow_context *subflow;
+	int i = 0;
+
 	data->sock = NULL;
 	data->call_again = 0;
 
+	mptcp_for_each_subflow(msk, subflow) {
+		if (i == MPTCP_SUBFLOWS_MAX) {
+			pr_warn_once("too many subflows");
+			break;
+		}
+		data->contexts[i++] = subflow;
+	}
+	data->subflows = i;
+
+	for (; i < MPTCP_SUBFLOWS_MAX; i++)
+		data->contexts[i++] = NULL;
+
 	return 0;
 }
 
diff --git a/tools/testing/selftests/bpf/bpf_tcp_helpers.h b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
index e17ce2b856bd..7fa96e3a8318 100644
--- a/tools/testing/selftests/bpf/bpf_tcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
@@ -231,10 +231,18 @@ extern __u32 tcp_slow_start(struct tcp_sock *tp, __u32 acked) __ksym;
 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, __u32 w, __u32 acked) __ksym;
 
 #define MPTCP_SCHED_NAME_MAX	16
+#define MPTCP_SUBFLOWS_MAX	8
+
+struct mptcp_subflow_context {
+	__u32	token;
+	struct	sock *tcp_sock;	    /* tcp sk backpointer */
+} __attribute__((preserve_access_index));
 
 struct mptcp_sched_data {
 	struct sock	*sock;
 	bool		call_again;
+	__u8		subflows;
+	struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
 };
 
 struct mptcp_sched_ops {
-- 
2.34.1