Use bitmap instead of sock in struct mptcp_sched_data.

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.

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

The BPF scheduler function get_subflow() has a struct mptcp_sched_data
parameter, which contains a mptcp_sched_subflow array. The struct
mptcp_sched_subflow has a member is_scheduled, it 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                           | 12 +++++++++---
 tools/testing/selftests/bpf/bpf_tcp_helpers.h | 16 +++++++++++++---
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 6456ea26e4c7..8a53583a9745 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -97,14 +97,20 @@ struct mptcp_out_options {
 };
 
 #define MPTCP_SCHED_NAME_MAX	16
+#define MPTCP_SUBFLOWS_MAX	8
+
+struct mptcp_sched_subflow {
+	struct mptcp_subflow_context *context;
+	bool	is_scheduled;
+};
 
 struct mptcp_sched_data {
-	struct sock	*sock;
-	bool		call_again;
+	bool	reinject;
+	struct mptcp_sched_subflow subflows[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/tools/testing/selftests/bpf/bpf_tcp_helpers.h b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
index aca4e3c6ac48..91900f2f047a 100644
--- a/tools/testing/selftests/bpf/bpf_tcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_tcp_helpers.h
@@ -231,10 +231,20 @@ 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;
+} __attribute__((preserve_access_index));
+
+struct mptcp_sched_subflow {
+	struct mptcp_subflow_context *context;
+	bool	is_scheduled;
+};
 
 struct mptcp_sched_data {
-	struct sock	*sock;
-	bool		call_again;
+	bool	reinject;
+	struct mptcp_sched_subflow subflows[MPTCP_SUBFLOWS_MAX];
 };
 
 struct mptcp_sched_ops {
@@ -243,7 +253,7 @@ 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