This patch adds a new member info_sent in struct mptcp_data_frag, save
info->sent in it, to support delay updating already_sent of dfrag until
all data are sent.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/protocol.c | 34 +++++++++++++++++++++++++++-------
 net/mptcp/protocol.h |  1 +
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index b1fef2b0c968..8ae8be76a09e 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1108,6 +1108,7 @@ mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag,
 	dfrag->data_seq = msk->write_seq;
 	dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag);
 	dfrag->offset = offset + sizeof(struct mptcp_data_frag);
+	dfrag->sent = 0;
 	dfrag->already_sent = 0;
 	dfrag->page = pfrag->page;
 
@@ -1243,8 +1244,8 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 	pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u",
 		 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent);
 
-	if (WARN_ON_ONCE(info->sent > info->limit ||
-			 info->limit > dfrag->data_len))
+	if (info->sent > info->limit ||
+	    info->limit > dfrag->data_len)
 		return 0;
 
 	if (unlikely(!__tcp_can_send(ssk)))
@@ -1496,11 +1497,11 @@ static void mptcp_update_post_push(struct mptcp_sock *msk,
 {
 	u64 snd_nxt_new = dfrag->data_seq;
 
-	dfrag->already_sent += sent;
+	dfrag->sent += sent;
 
 	msk->snd_burst -= sent;
 
-	snd_nxt_new += dfrag->already_sent;
+	snd_nxt_new += dfrag->sent;
 
 	/* snd_nxt_new can be smaller than snd_nxt in case mptcp
 	 * is recovering after a failover. In that event, this re-sends
@@ -1523,6 +1524,23 @@ static void mptcp_update_first_pending(struct sock *sk, struct mptcp_sendmsg_inf
 		WRITE_ONCE(msk->first_pending, mptcp_next_frag(sk, info->last_frag));
 }
 
+static void mptcp_update_dfrags(struct sock *sk, struct mptcp_sendmsg_info *info)
+{
+	struct mptcp_data_frag *dfrag = mptcp_send_head(sk);
+
+	if (!dfrag)
+		return;
+
+	do {
+		if (dfrag->sent) {
+			dfrag->already_sent = max(dfrag->already_sent, dfrag->sent);
+			dfrag->sent = 0;
+		}
+	} while ((dfrag = mptcp_next_frag(sk, dfrag)));
+
+	mptcp_update_first_pending(sk, info);
+}
+
 void mptcp_check_and_set_pending(struct sock *sk)
 {
 	if (mptcp_send_head(sk))
@@ -1546,6 +1564,7 @@ static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
 		info->sent = dfrag->already_sent;
 		info->limit = dfrag->data_len;
 		len = dfrag->data_len - dfrag->already_sent;
+		dfrag->sent = info->sent;
 		while (len > 0) {
 			int ret = 0;
 
@@ -1556,6 +1575,7 @@ static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
 			}
 
 			info->sent += ret;
+			info->limit -= ret;
 			copied += ret;
 			len -= ret;
 
@@ -1619,7 +1639,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
 				mptcp_subflow_set_scheduled(subflow, false);
 			}
 		}
-		mptcp_update_first_pending(sk, &info);
+		mptcp_update_dfrags(sk, &info);
 	}
 
 	/* at this point we held the socket lock for the last subflow we used */
@@ -1658,7 +1678,7 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool
 					goto again;
 				break;
 			}
-			mptcp_update_first_pending(sk, &info);
+			mptcp_update_dfrags(sk, &info);
 			continue;
 		}
 
@@ -1686,7 +1706,7 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool
 				mptcp_subflow_set_scheduled(subflow, false);
 			}
 		}
-		mptcp_update_first_pending(sk, &info);
+		mptcp_update_dfrags(sk, &info);
 	}
 
 out:
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 118fe5a2745c..f60520bfdb7d 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -242,6 +242,7 @@ struct mptcp_data_frag {
 	u16 data_len;
 	u16 offset;
 	u16 overhead;
+	u16 sent;
 	u16 already_sent;
 	struct page *page;
 };
-- 
2.35.3