1 files changed, 26 insertions, 25 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 4cd0b50d4e46..53ce6cf55598 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -357,14 +357,10 @@ static void tcp_ecn_clear_syn(struct sock *sk, struct sk_buff *skb)
 }
 
 static void
-tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th,
-                    struct sock *sk)
+tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th)
 {
-        if (inet_rsk(req)->ecn_ok) {
+        if (inet_rsk(req)->ecn_ok)
                 th->ece = 1;
-                if (tcp_ca_needs_ecn(sk))
-                        INET_ECN_xmit(sk);
-        }
 }
 
 /* Set up ECN state for a packet on a ESTABLISHED socket that is about to
@@ -612,12 +608,11 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 }
 
 /* Set up TCP options for SYN-ACKs. */
-static unsigned int tcp_synack_options(struct sock *sk,
-                                   struct request_sock *req,
-                                   unsigned int mss, struct sk_buff *skb,
-                                   struct tcp_out_options *opts,
-                                   const struct tcp_md5sig_key *md5,
-                                   struct tcp_fastopen_cookie *foc)
+static unsigned int tcp_synack_options(struct request_sock *req,
+                                       unsigned int mss, struct sk_buff *skb,
+                                       struct tcp_out_options *opts,
+                                       const struct tcp_md5sig_key *md5,
+                                       struct tcp_fastopen_cookie *foc)
 {
         struct inet_request_sock *ireq = inet_rsk(req);
         unsigned int remaining = MAX_TCP_OPTION_SPACE;
@@ -2949,20 +2944,25 @@ int tcp_send_synack(struct sock *sk)
  * Allocate one skb and build a SYNACK packet.
  * @dst is consumed : Caller should not use it again.
  */
-struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
+struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
                                 struct request_sock *req,
                                 struct tcp_fastopen_cookie *foc)
 {
-        struct tcp_out_options opts;
         struct inet_request_sock *ireq = inet_rsk(req);
-        struct tcp_sock *tp = tcp_sk(sk);
-        struct tcphdr *th;
-        struct sk_buff *skb;
+        const struct tcp_sock *tp = tcp_sk(sk);
         struct tcp_md5sig_key *md5 = NULL;
+        struct tcp_out_options opts;
+        struct sk_buff *skb;
         int tcp_header_size;
+        struct tcphdr *th;
+        u16 user_mss;
         int mss;
 
-        skb = sock_wmalloc(sk, MAX_TCP_HEADER, 1, GFP_ATOMIC);
+        /* sk is a const pointer, because we want to express multiple cpus
+         * might call us concurrently.
+         * sock_wmalloc() will change sk->sk_wmem_alloc in an atomic way.
+         */
+        skb = sock_wmalloc((struct sock *)sk, MAX_TCP_HEADER, 1, GFP_ATOMIC);
         if (unlikely(!skb)) {
                 dst_release(dst);
                 return NULL;
@@ -2973,8 +2973,9 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
         skb_dst_set(skb, dst);
 
         mss = dst_metric_advmss(dst);
-        if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss)
-                mss = tp->rx_opt.user_mss;
+        user_mss = READ_ONCE(tp->rx_opt.user_mss);
+        if (user_mss && user_mss < mss)
+                mss = user_mss;
 
         memset(&opts, 0, sizeof(opts));
 #ifdef CONFIG_SYN_COOKIES
@@ -2989,8 +2990,8 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
         md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, req_to_sk(req));
 #endif
         skb_set_hash(skb, tcp_rsk(req)->txhash, PKT_HASH_TYPE_L4);
-        tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, md5,
-                                             foc) + sizeof(*th);
+        tcp_header_size = tcp_synack_options(req, mss, skb, &opts, md5, foc) +
+                          sizeof(*th);
 
         skb_push(skb, tcp_header_size);
         skb_reset_transport_header(skb);
@@ -2999,7 +3000,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
         memset(th, 0, sizeof(struct tcphdr));
         th->syn = 1;
         th->ack = 1;
-        tcp_ecn_make_synack(req, th, sk);
+        tcp_ecn_make_synack(req, th);
         th->source = htons(ireq->ir_num);
         th->dest = ireq->ir_rmt_port;
         /* Setting of flags are superfluous here for callers (and ECE is
@@ -3014,7 +3015,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 
         /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */
         th->window = htons(min(req->rcv_wnd, 65535U));
-        tcp_options_write((__be32 *)(th + 1), tp, &opts);
+        tcp_options_write((__be32 *)(th + 1), NULL, &opts);
         th->doff = (tcp_header_size >> 2);
         TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_OUTSEGS);
 
@@ -3501,7 +3502,7 @@ void tcp_send_probe0(struct sock *sk)
                                   TCP_RTO_MAX);
 }
 
-int tcp_rtx_synack(struct sock *sk, struct request_sock *req)
+int tcp_rtx_synack(const struct sock *sk, struct request_sock *req)
 {
         const struct tcp_request_sock_ops *af_ops = tcp_rsk(req)->af_specific;
         struct flowi fl;