Use new BPF API.

Please update the commit log:

'''
This patch defines struct mptcp_sched_ops, which has three struct members,
name, owner and list, and three function pointers, init(), release() and
get_subflow().

The scheduler function get_subflow() has a struct mptcp_sched_data
parameter, which contains a reinject flag and a mptcp_subflow_context
array.

Add the scheduler registering, unregistering and finding functions to add,
delete and find a packet scheduler on the global list mptcp_sched_list.

Add a new member scheduled in struct mptcp_subflow_context, which will be
set in the MPTCP scheduler context when the scheduler picks this subflow
to send data.
'''

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 include/net/mptcp.h                           |  7 ++++---
 net/mptcp/protocol.h                          |  1 +
 tools/testing/selftests/bpf/bpf_tcp_helpers.h | 11 ++++++++---
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 6456ea26e4c7..7af7fd48acc7 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -97,14 +97,15 @@ 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;
+	bool	reinject;
+	struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
 };
 
 struct mptcp_sched_ops {
-	void (*get_subflow)(const struct mptcp_sock *msk, bool reinject,
+	void (*get_subflow)(const struct mptcp_sock *msk,
 			    struct mptcp_sched_data *data);
 
 	char			name[MPTCP_SCHED_NAME_MAX];
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 8739794166d8..48c5261b7b15 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -469,6 +469,7 @@ struct mptcp_subflow_context {
 		valid_csum_seen : 1;        /* at least one csum validated */
 	enum mptcp_data_avail data_avail;
 	bool	mp_fail_response_expect;
+	bool	scheduled;
 	u32	remote_nonce;
 	u64	thmac;
 	u32	local_nonce;
diff --git a/tools/testing/selftests/bpf/bpf_tcp_helpers.h b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
index aca4e3c6ac48..8338c7b31f87 100644
--- a/tools/testing/selftests/bpf/bpf_tcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
@@ -231,10 +231,15 @@ 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 {
+	struct	sock *tcp_sock;	    /* tcp sk backpointer */
+} __attribute__((preserve_access_index));
 
 struct mptcp_sched_data {
-	struct sock	*sock;
-	bool		call_again;
+	bool	reinject;
+	struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
 };
 
 struct mptcp_sched_ops {
@@ -243,7 +248,7 @@ struct mptcp_sched_ops {
 	void (*init)(const struct mptcp_sock *msk);
 	void (*release)(const struct mptcp_sock *msk);
 
-	void (*get_subflow)(const struct mptcp_sock *msk, bool reinject,
+	void (*get_subflow)(const struct mptcp_sock *msk,
 			    struct mptcp_sched_data *data);
 	void *owner;
 };
-- 
2.34.1