This patch defines two packet scheduler wrappers mptcp_sched_get_send()
and mptcp_sched_get_retrans(), invoke data_init() and get_subflow() of
msk->sched in them.

Set data->reinject to true in mptcp_sched_get_retrans(), set it false in
mptcp_sched_get_send().

If msk->sched is NULL, use default functions mptcp_subflow_get_send()
and mptcp_subflow_get_retrans() to send data.

Move sock_owned_by_me() check and fallback check into the wrappers from
mptcp_subflow_get_send() and mptcp_subflow_get_retrans().

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/protocol.c | 14 -----------
 net/mptcp/protocol.h |  4 ++++
 net/mptcp/sched.c    | 55 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 14 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 93c2b5d71254..8974ce86fbad 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1418,15 +1418,6 @@ struct sock *mptcp_subflow_get_send(const struct mptcp_sock *msk,
 	u64 linger_time;
 	long tout = 0;
 
-	sock_owned_by_me(sk);
-
-	if (__mptcp_check_fallback(msk)) {
-		if (!msk->first)
-			return NULL;
-		return __tcp_can_send(msk->first) &&
-		       sk_stream_memory_free(msk->first) ? msk->first : NULL;
-	}
-
 	/* pick the subflow with the lower wmem/wspace ratio */
 	for (i = 0; i < SSK_MODE_MAX; ++i) {
 		send_info[i].ssk = NULL;
@@ -2190,11 +2181,6 @@ struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk)
 	struct mptcp_subflow_context *subflow;
 	int min_stale_count = INT_MAX;
 
-	sock_owned_by_me((const struct sock *)msk);
-
-	if (__mptcp_check_fallback(msk))
-		return NULL;
-
 	mptcp_for_each_subflow(msk, subflow) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index cdea1efb14a5..95500d0293fb 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -642,6 +642,10 @@ void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
 struct sock *mptcp_subflow_get_send(const struct mptcp_sock *msk,
 				    struct mptcp_sched_data *data);
 struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk);
+int mptcp_sched_get_send(struct mptcp_sock *msk,
+			 struct mptcp_sched_data *data);
+int mptcp_sched_get_retrans(struct mptcp_sock *msk,
+			    struct mptcp_sched_data *data);
 
 static inline bool __tcp_can_send(const struct sock *ssk)
 {
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
index 92057ca94cf4..fd29797af3bc 100644
--- a/net/mptcp/sched.c
+++ b/net/mptcp/sched.c
@@ -146,3 +146,58 @@ void mptcp_sched_data_set_contexts(const struct mptcp_sock *msk,
 	for (; i < MPTCP_SUBFLOWS_MAX; i++)
 		data->contexts[i] = NULL;
 }
+
+int mptcp_sched_get_send(struct mptcp_sock *msk,
+			 struct mptcp_sched_data *data)
+{
+	struct sock *ssk = NULL;
+
+	sock_owned_by_me((const struct sock *)msk);
+
+	/* the following check is moved out of mptcp_subflow_get_send */
+	if (__mptcp_check_fallback(msk)) {
+		if (msk->first &&
+		    __tcp_can_send(msk->first) &&
+		    sk_stream_memory_free(msk->first)) {
+			mptcp_subflow_set_scheduled(mptcp_subflow_ctx(msk->first), true);
+			return 0;
+		}
+		return -EINVAL;
+	}
+
+	if (!msk->sched) {
+		ssk = mptcp_subflow_get_send(msk, data);
+		if (!ssk)
+			return -EINVAL;
+		mptcp_subflow_set_scheduled(mptcp_subflow_ctx(ssk), true);
+		return 0;
+	}
+
+	data->reinject = false;
+	msk->sched->data_init(msk, data);
+	return msk->sched->get_subflow(msk, data);
+}
+
+int mptcp_sched_get_retrans(struct mptcp_sock *msk,
+			    struct mptcp_sched_data *data)
+{
+	struct sock *ssk = NULL;
+
+	sock_owned_by_me((const struct sock *)msk);
+
+	/* the following check is moved out of mptcp_subflow_get_retrans */
+	if (__mptcp_check_fallback(msk))
+		return -EINVAL;
+
+	if (!msk->sched) {
+		ssk = mptcp_subflow_get_retrans(msk);
+		if (!ssk)
+			return -EINVAL;
+		mptcp_subflow_set_scheduled(mptcp_subflow_ctx(ssk), true);
+		return 0;
+	}
+
+	data->reinject = true;
+	msk->sched->data_init(msk, data);
+	return msk->sched->get_subflow(msk, data);
+}
-- 
2.35.3