tcp: Use NET_ADD_STATS instead of NET_ADD_STATS_BH in tcp_event_new_data_sent()

Can be invoked from non-BH context.

Based upon a patch by Eric Dumazet.

Fixes: f19c29e3 ("tcp: snmp stats for Fast Open, SYN rtx, and data pkts")
Reported-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -187,6 +187,7 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
 #define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
 #define NET_INC_STATS_BH(net, field)	SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 #define NET_INC_STATS_USER(net, field) 	SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
+#define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 

net/ipv4/tcp_output.c

@@ -87,8 +87,8 @@ static void tcp_event_new_data_sent(struct sock *sk, const struct sk_buff *skb)
 		tcp_rearm_rto(sk);
 	}
 
-	NET_ADD_STATS_BH(sock_net(sk), LINUX_MIB_TCPORIGDATASENT,
-			 tcp_skb_pcount(skb));
+	NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPORIGDATASENT,
+		      tcp_skb_pcount(skb));
 }
 
 /* SND.NXT, if window was not shrunk.