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);
 }
 
 
        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;
 
 
        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;
 }
                WRITE_ONCE(msk->first, NULL);
 
 out:
-       if (ssk == msk->last_snd)
-               msk->last_snd = NULL;
-
        if (need_push)
                __mptcp_push_pending(sk, 0);
 }
         * 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;
                        __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);
 
 #define MPTCP_RETRANSMIT       4
 #define MPTCP_FLUSH_JOIN_LIST  5
 #define MPTCP_CONNECTED                6
-#define MPTCP_RESET_SCHEDULER  7
 
 struct mptcp_skb_cb {
        u64 map_seq;
        u64             rcv_data_fin_seq;
        u64             bytes_retrans;
        int             rmem_fwd_alloc;
-       struct sock     *last_snd;
        int             snd_burst;
        int             old_wspace;
        u64             recovery_snd_nxt;       /* in recovery mode accept up to this seq;