1 files changed, 34 insertions, 2 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 577075713ad5..7420299c31f5 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -299,6 +299,7 @@ struct cg_proto;
   *	@sk_filter: socket filtering instructions
   *	@sk_timer: sock cleanup timer
   *	@sk_stamp: time stamp of last packet received
+  *	@sk_stamp_seq: lock for accessing sk_stamp on 32 bit architectures only
   *	@sk_tsflags: SO_TIMESTAMPING socket options
   *	@sk_tskey: counter to disambiguate concurrent tstamp requests
   *	@sk_socket: Identd and reporting IO signals
@@ -434,6 +435,9 @@ struct sock {
 	long			sk_sndtimeo;
 	struct timer_list	sk_timer;
 	ktime_t			sk_stamp;
+#if BITS_PER_LONG==32
+	seqlock_t		sk_stamp_seq;
+#endif
 	u16			sk_tsflags;
 	u32			sk_tskey;
 	struct socket		*sk_socket;
@@ -2146,6 +2150,34 @@ static inline void sk_drops_add(struct sock *sk, const struct sk_buff *skb)
 	atomic_add(segs, &sk->sk_drops);
 }
 
+static inline ktime_t sock_read_timestamp(struct sock *sk)
+{
+#if BITS_PER_LONG==32
+	unsigned int seq;
+	ktime_t kt;
+
+	do {
+		seq = read_seqbegin(&sk->sk_stamp_seq);
+		kt = sk->sk_stamp;
+	} while (read_seqretry(&sk->sk_stamp_seq, seq));
+
+	return kt;
+#else
+	return sk->sk_stamp;
+#endif
+}
+
+static inline void sock_write_timestamp(struct sock *sk, ktime_t kt)
+{
+#if BITS_PER_LONG==32
+	write_seqlock(&sk->sk_stamp_seq);
+	sk->sk_stamp = kt;
+	write_sequnlock(&sk->sk_stamp_seq);
+#else
+	sk->sk_stamp = kt;
+#endif
+}
+
 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
 			   struct sk_buff *skb);
 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
@@ -2170,7 +2202,7 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
 	     (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
 		__sock_recv_timestamp(msg, sk, skb);
 	else
-		sk->sk_stamp = kt;
+		sock_write_timestamp(sk, kt);
 
 	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
 		__sock_recv_wifi_status(msg, sk, skb);
@@ -2190,7 +2222,7 @@ static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
 	if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY)
 		__sock_recv_ts_and_drops(msg, sk, skb);
 	else
-		sk->sk_stamp = skb->tstamp;
+		sock_write_timestamp(sk, skb->tstamp);
 }
 
 void __sock_tx_timestamp(const struct sock *sk, __u8 *tx_flags);