Patch "tcp: cleanup tcp_remove_empty_skb() use" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tcp: cleanup tcp_remove_empty_skb() use

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tcp-cleanup-tcp_remove_empty_skb-use.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit a97a36302ef8c48118b1973810eabe8f097822e9
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date:   Wed Oct 27 13:19:18 2021 -0700

    tcp: cleanup tcp_remove_empty_skb() use
    
    [ Upstream commit 27728ba80f1eb279b209bbd5922fdeebe52d9e30 ]
    
    All tcp_remove_empty_skb() callers now use tcp_write_queue_tail()
    for the skb argument, we can therefore factorize code.
    
    Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Stable-dep-of: 72377ab2d671 ("mptcp: more conservative check for zero probes")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e93a48edf438c..3aee02ad0116b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -314,7 +314,7 @@ void tcp_shutdown(struct sock *sk, int how);
 int tcp_v4_early_demux(struct sk_buff *skb);
 int tcp_v4_rcv(struct sk_buff *skb);
 
-void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb);
+void tcp_remove_empty_skb(struct sock *sk);
 int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
 int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2115a0e5c98f7..6dcb77a2bde60 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -953,8 +953,10 @@ int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
  * importantly be able to generate EPOLLOUT for Edge Trigger epoll()
  * users.
  */
-void tcp_remove_empty_skb(struct sock *sk, struct sk_buff *skb)
+void tcp_remove_empty_skb(struct sock *sk)
 {
+	struct sk_buff *skb = tcp_write_queue_tail(sk);
+
 	if (skb && TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
 		tcp_unlink_write_queue(skb, sk);
 		if (tcp_write_queue_empty(sk))
@@ -1107,7 +1109,7 @@ ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
 	return copied;
 
 do_error:
-	tcp_remove_empty_skb(sk, tcp_write_queue_tail(sk));
+	tcp_remove_empty_skb(sk);
 	if (copied)
 		goto out;
 out_err:
@@ -1429,8 +1431,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 	return copied + copied_syn;
 
 do_error:
-	skb = tcp_write_queue_tail(sk);
-	tcp_remove_empty_skb(sk, skb);
+	tcp_remove_empty_skb(sk);
 
 	if (copied + copied_syn)
 		goto out;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 82b1583f709d3..b9613e02e2de1 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1338,7 +1338,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 		u64 snd_una = READ_ONCE(msk->snd_una);
 
 		if (snd_una != msk->snd_nxt) {
-			tcp_remove_empty_skb(ssk, tcp_write_queue_tail(ssk));
+			tcp_remove_empty_skb(ssk);
 			return 0;
 		}
 
@@ -1354,7 +1354,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 
 	copy = min_t(size_t, copy, info->limit - info->sent);
 	if (!sk_wmem_schedule(ssk, copy)) {
-		tcp_remove_empty_skb(ssk, tcp_write_queue_tail(ssk));
+		tcp_remove_empty_skb(ssk);
 		return -ENOMEM;
 	}