[PATCH net 1/2] mptcp: Consistently use READ_ONCE/WRITE_ONCE with msk->ack_seq

[Mat Martineau]

The msk->ack_seq value is sometimes read without the msk lock held, so
make proper use of READ_ONCE and WRITE_ONCE.

Signed-off-by: Mat Martineau <mathew.j.martin...@linux.intel.com>
---
 net/mptcp/options.c  | 4 ++--
 net/mptcp/protocol.c | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 7fa822b55c34..120ef39fe589 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -518,11 +518,11 @@ static bool mptcp_established_options_dss(struct sock 
*sk, struct sk_buff *skb,
 
        if (subflow->use_64bit_ack) {
                ack_size = TCPOLEN_MPTCP_DSS_ACK64;
-               opts->ext_copy.data_ack = msk->ack_seq;
+               opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
                opts->ext_copy.ack64 = 1;
        } else {
                ack_size = TCPOLEN_MPTCP_DSS_ACK32;
-               opts->ext_copy.data_ack32 = (uint32_t)(msk->ack_seq);
+               opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);
                opts->ext_copy.ack64 = 0;
        }
        opts->ext_copy.use_ack = 1;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 365ba96c84b0..5d747c6a610e 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -123,7 +123,7 @@ static void __mptcp_move_skb(struct mptcp_sock *msk, struct 
sock *ssk,
 
        skb_ext_reset(skb);
        skb_orphan(skb);
-       msk->ack_seq += copy_len;
+       WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len);
 
        tail = skb_peek_tail(&sk->sk_receive_queue);
        if (offset == 0 && tail) {
@@ -261,7 +261,7 @@ static void mptcp_check_data_fin(struct sock *sk)
        if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) {
                struct mptcp_subflow_context *subflow;
 
-               msk->ack_seq++;
+               WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1);
                WRITE_ONCE(msk->rcv_data_fin, 0);
 
                sk->sk_shutdown |= RCV_SHUTDOWN;
@@ -1720,7 +1720,7 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
                msk->remote_key = mp_opt->sndr_key;
                mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
                ack_seq++;
-               msk->ack_seq = ack_seq;
+               WRITE_ONCE(msk->ack_seq, ack_seq);
        }
 
        sock_reset_flag(nsk, SOCK_RCU_FREE);
@@ -2072,7 +2072,7 @@ bool mptcp_finish_join(struct sock *sk)
        parent_sock = READ_ONCE(parent->sk_socket);
        if (parent_sock && !sk->sk_socket)
                mptcp_sock_graft(sk, parent_sock);
-       subflow->map_seq = msk->ack_seq;
+       subflow->map_seq = READ_ONCE(msk->ack_seq);
        return true;
 }
 
-- 
2.28.0