[PATCH mptcp-next v6 05/13] mptcp: simplify push_pending

[Geliang Tang <geliang.tang@suse.com>]

This patch moves the duplicate code from __mptcp_push_pending() and
__mptcp_subflow_push_pending() into a new helper function, named
__subflow_push_pending(). And simplify __mptcp_push_pending() by
invoking this helper.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/protocol.c | 95 +++++++++++++++++++++++++-------------------
 1 file changed, 54 insertions(+), 41 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 7d5f89799c9a..817e539d1d12 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1480,12 +1480,6 @@ struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
 	return ssk;
 }
 
-static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
-{
-	tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
-	release_sock(ssk);
-}
-
 static void mptcp_update_post_push(struct mptcp_sock *msk,
 				   struct mptcp_data_frag *dfrag,
 				   u32 sent)
@@ -1517,61 +1511,80 @@ void mptcp_check_and_set_pending(struct sock *sk)
 		mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING);
 }
 
+static int __subflow_push_pending(struct sock *sk, struct sock *ssk,
+				  struct mptcp_sendmsg_info *info)
+{
+	struct mptcp_sock *msk = mptcp_sk(sk);
+	struct mptcp_data_frag *dfrag;
+	int len, copied = 0, err = 0;
+
+	while ((dfrag = mptcp_send_head(sk))) {
+		info->sent = dfrag->already_sent;
+		info->limit = dfrag->data_len;
+		len = dfrag->data_len - dfrag->already_sent;
+		while (len > 0) {
+			int ret = 0;
+
+			ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info);
+			if (ret <= 0) {
+				err = copied ? : ret;
+				goto out;
+			}
+
+			info->sent += ret;
+			copied += ret;
+			len -= ret;
+
+			mptcp_update_post_push(msk, dfrag, ret);
+		}
+		WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
+
+		if (msk->snd_burst <= 0 ||
+		    !sk_stream_memory_free(ssk) ||
+		    !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) {
+			err = copied ? : -EAGAIN;
+			goto out;
+		}
+		mptcp_set_timeout(sk);
+	}
+	err = copied;
+
+out:
+	if (copied) {
+		tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle,
+			 info->size_goal);
+	}
+
+	return err;
+}
+
 void __mptcp_push_pending(struct sock *sk, unsigned int flags)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_sendmsg_info info = {
 				.flags = flags,
 	};
-	bool do_check_data_fin = false;
-	struct mptcp_data_frag *dfrag;
 	struct sock *ssk;
-	int len;
+	int ret = 0;
 
 again:
 	while (mptcp_send_head(sk) && (ssk = mptcp_subflow_get_send(msk))) {
 		lock_sock(ssk);
+		ret = __subflow_push_pending(sk, ssk, &info);
+		release_sock(ssk);
 
-		while ((dfrag = mptcp_send_head(sk))) {
-			info.sent = dfrag->already_sent;
-			info.limit = dfrag->data_len;
-			len = dfrag->data_len - dfrag->already_sent;
-			while (len > 0) {
-				int ret = 0;
-
-				ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
-				if (ret <= 0) {
-					mptcp_push_release(ssk, &info);
-					if (ret == -EAGAIN)
-						goto again;
-					goto out;
-				}
-
-				do_check_data_fin = true;
-				info.sent += ret;
-				len -= ret;
-
-				mptcp_update_post_push(msk, dfrag, ret);
-			}
-			WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
-
-			if (msk->snd_burst <= 0 ||
-			    !sk_stream_memory_free(ssk) ||
-			    !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) {
-				mptcp_push_release(ssk, &info);
+		if (ret <= 0) {
+			if (ret == -EAGAIN)
 				goto again;
-			}
-			mptcp_set_timeout(sk);
+			goto out;
 		}
-
-		mptcp_push_release(ssk, &info);
 	}
 
 out:
 	/* ensure the rtx timer is running */
 	if (!mptcp_timer_pending(sk))
 		mptcp_reset_timer(sk);
-	if (do_check_data_fin)
+	if (ret > 0)
 		__mptcp_check_send_data_fin(sk);
 }
 
-- 
2.35.3