msk->last_snd is no longer used anymore in burst scheduler, now it is
used for the round-robin BPF MPTCP scheduler only. This patch removes
the last_snd related code for burst scheduler.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/pm.c         |  9 +--------
 net/mptcp/pm_netlink.c |  3 ---
 net/mptcp/protocol.c   | 11 +----------
 net/mptcp/protocol.h   |  1 -
 net/mptcp/sched.c      |  2 ++
 5 files changed, 4 insertions(+), 22 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 45e2a48397b9..cdeb7280ac76 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -282,15 +282,8 @@ void mptcp_pm_mp_prio_received(struct sock *ssk, u8 bkup)
 
 	pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup);
 	msk = mptcp_sk(sk);
-	if (subflow->backup != bkup) {
+	if (subflow->backup != bkup)
 		subflow->backup = bkup;
-		mptcp_data_lock(sk);
-		if (!sock_owned_by_user(sk))
-			msk->last_snd = NULL;
-		else
-			__set_bit(MPTCP_RESET_SCHEDULER,  &msk->cb_flags);
-		mptcp_data_unlock(sk);
-	}
 
 	mptcp_event(MPTCP_EVENT_SUB_PRIORITY, msk, ssk, GFP_ATOMIC);
 }
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 9813ed0fde9b..1f2da4aedcb4 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -475,9 +475,6 @@ static void __mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_con
 
 	slow = lock_sock_fast(ssk);
 	if (prio) {
-		if (subflow->backup != backup)
-			msk->last_snd = NULL;
-
 		subflow->send_mp_prio = 1;
 		subflow->backup = backup;
 		subflow->request_bkup = backup;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index bf77defbc546..8708e1e4ba16 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1469,16 +1469,13 @@ struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
 
 	burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt);
 	wmem = READ_ONCE(ssk->sk_wmem_queued);
-	if (!burst) {
-		msk->last_snd = NULL;
+	if (!burst)
 		return ssk;
-	}
 
 	subflow = mptcp_subflow_ctx(ssk);
 	subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem +
 					   READ_ONCE(ssk->sk_pacing_rate) * burst,
 					   burst + wmem);
-	msk->last_snd = ssk;
 	msk->snd_burst = burst;
 	return ssk;
 }
@@ -2343,9 +2340,6 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		msk->first = NULL;
 
 out:
-	if (ssk == msk->last_snd)
-		msk->last_snd = NULL;
-
 	if (need_push)
 		__mptcp_push_pending(sk, 0);
 }
@@ -2978,7 +2972,6 @@ static int mptcp_disconnect(struct sock *sk, int flags)
 	 * subflow
 	 */
 	mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE);
-	msk->last_snd = NULL;
 	WRITE_ONCE(msk->flags, 0);
 	msk->cb_flags = 0;
 	msk->push_pending = 0;
@@ -3239,8 +3232,6 @@ static void mptcp_release_cb(struct sock *sk)
 			__mptcp_set_connected(sk);
 		if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
 			__mptcp_error_report(sk);
-		if (__test_and_clear_bit(MPTCP_RESET_SCHEDULER, &msk->cb_flags))
-			msk->last_snd = NULL;
 	}
 
 	__mptcp_update_rmem(sk);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index e81399debff9..05f4c6fd0cd8 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -124,7 +124,6 @@
 #define MPTCP_RETRANSMIT	4
 #define MPTCP_FLUSH_JOIN_LIST	5
 #define MPTCP_CONNECTED		6
-#define MPTCP_RESET_SCHEDULER	7
 
 static inline bool before64(__u64 seq1, __u64 seq2)
 {
diff --git a/net/mptcp/sched.c b/net/mptcp/sched.c
index d1cad1eefb35..3d805760ae99 100644
--- a/net/mptcp/sched.c
+++ b/net/mptcp/sched.c
@@ -67,6 +67,7 @@ int mptcp_init_sched(struct mptcp_sock *msk,
 	msk->sched = sched;
 	if (msk->sched->init)
 		msk->sched->init(msk);
+	msk->last_snd = NULL;
 
 	pr_debug("sched=%s", msk->sched->name);
 
@@ -84,6 +85,7 @@ void mptcp_release_sched(struct mptcp_sock *msk)
 	msk->sched = NULL;
 	if (sched->release)
 		sched->release(msk);
+	msk->last_snd = NULL;
 
 	bpf_module_put(sched, sched->owner);
 }
-- 
2.35.3