Patch "mptcp: add sk_stop_timer_sync helper" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    mptcp: add sk_stop_timer_sync helper

to the 4.19-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:
     mptcp-add-sk_stop_timer_sync-helper.patch
and it can be found in the queue-4.19 subdirectory.

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



commit 5f74f96173e3cfa084a07b98e927f8d86bcda30f
Author: Geliang Tang <geliang@xxxxxxxxxx>
Date:   Thu Sep 24 08:30:01 2020 +0800

    mptcp: add sk_stop_timer_sync helper
    
    [ Upstream commit 08b81d873126b413cda511b1ea1cbb0e99938bbd ]
    
    This patch added a new helper sk_stop_timer_sync, it deactivates a timer
    like sk_stop_timer, but waits for the handler to finish.
    
    Acked-by: Paolo Abeni <pabeni@xxxxxxxxxx>
    Signed-off-by: Geliang Tang <geliangtang@xxxxxxxxx>
    Reviewed-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Stable-dep-of: 151c9c724d05 ("tcp: properly terminate timers for kernel sockets")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/include/net/sock.h b/include/net/sock.h
index 81888513b3b93..8eea17a41c1ca 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2194,6 +2194,8 @@ void sk_reset_timer(struct sock *sk, struct timer_list *timer,
 
 void sk_stop_timer(struct sock *sk, struct timer_list *timer);
 
+void sk_stop_timer_sync(struct sock *sk, struct timer_list *timer);
+
 int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue,
 			struct sk_buff *skb, unsigned int flags,
 			void (*destructor)(struct sock *sk,
diff --git a/net/core/sock.c b/net/core/sock.c
index 62d169bcfcfa1..eaa6f1ca414d0 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2804,6 +2804,13 @@ void sk_stop_timer(struct sock *sk, struct timer_list* timer)
 }
 EXPORT_SYMBOL(sk_stop_timer);
 
+void sk_stop_timer_sync(struct sock *sk, struct timer_list *timer)
+{
+	if (del_timer_sync(timer))
+		__sock_put(sk);
+}
+EXPORT_SYMBOL(sk_stop_timer_sync);
+
 void sock_init_data(struct socket *sock, struct sock *sk)
 {
 	sk_init_common(sk);