4 files changed, 17 insertions, 4 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 3b2911502a8c..e8bbf403618f 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -158,6 +158,8 @@ struct tcp_sock {
                                  * sum(delta(snd_una)), or how many bytes
                                  * were acked.
                                  */
+        struct u64_stats_sync syncp; /* protects 64bit vars (cf tcp_get_info()) */
+
         u32     snd_una;        /* First byte we want an ack for        */
         u32     snd_sml;        /* Last byte of the most recently transmitted small packet */
         u32     rcv_tstamp;     /* timestamp of last received ACK (for keepalives) */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 46efa03d2b11..f1377f2a0472 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -402,6 +402,7 @@ void tcp_init_sock(struct sock *sk)
         tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
         tp->snd_cwnd_clamp = ~0;
         tp->mss_cache = TCP_MSS_DEFAULT;
+        u64_stats_init(&tp->syncp);
 
         tp->reordering = sysctl_tcp_reordering;
         tcp_enable_early_retrans(tp);
@@ -2598,6 +2599,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
         const struct tcp_sock *tp = tcp_sk(sk);
         const struct inet_connection_sock *icsk = inet_csk(sk);
         u32 now = tcp_time_stamp;
+        unsigned int start;
         u32 rate;
 
         memset(info, 0, sizeof(*info));
@@ -2665,10 +2667,11 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
         rate = READ_ONCE(sk->sk_max_pacing_rate);
         info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL;
 
-        spin_lock_bh(&sk->sk_lock.slock);
-        info->tcpi_bytes_acked = tp->bytes_acked;
-        info->tcpi_bytes_received = tp->bytes_received;
-        spin_unlock_bh(&sk->sk_lock.slock);
+        do {
+                start = u64_stats_fetch_begin_irq(&tp->syncp);
+                info->tcpi_bytes_acked = tp->bytes_acked;
+                info->tcpi_bytes_received = tp->bytes_received;
+        } while (u64_stats_fetch_retry_irq(&tp->syncp, start));
 }
 EXPORT_SYMBOL_GPL(tcp_get_info);
 
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 3c673d5e6cff..46b087a27503 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -206,6 +206,10 @@ static bool tcp_fastopen_create_child(struct sock *sk,
                         skb_set_owner_r(skb2, child);
                         __skb_queue_tail(&child->sk_receive_queue, skb2);
                         tp->syn_data_acked = 1;
+
+                        /* u64_stats_update_begin(&tp->syncp) not needed here,
+                         * as we certainly are not changing upper 32bit value (0)
+                         */
                         tp->bytes_received = end_seq - TCP_SKB_CB(skb)->seq - 1;
                 } else {
                         end_seq = TCP_SKB_CB(skb)->seq + 1;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 243d674b3ef5..c9ab964189a0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3286,7 +3286,9 @@ static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack)
 {
         u32 delta = ack - tp->snd_una;
 
+        u64_stats_update_begin(&tp->syncp);
         tp->bytes_acked += delta;
+        u64_stats_update_end(&tp->syncp);
         tp->snd_una = ack;
 }
 
@@ -3295,7 +3297,9 @@ static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq)
 {
         u32 delta = seq - tp->rcv_nxt;
 
+        u64_stats_update_begin(&tp->syncp);
         tp->bytes_received += delta;
+        u64_stats_update_end(&tp->syncp);
         tp->rcv_nxt = seq;
 }