net: snmp: kill various STATS_USER() helpers

In the old days (before linux-3.0), SNMP counters were duplicated,
one for user context, and one for BH context.

After commit 8f0ea0fe ("snmp: reduce percpu needs by 50%")
we have a single copy, and what really matters is preemption being
enabled or disabled, since we use this_cpu_inc() or __this_cpu_inc()
respectively.

We therefore kill SNMP_INC_STATS_USER(), SNMP_ADD_STATS_USER(),
NET_INC_STATS_USER(), NET_ADD_STATS_USER(), SCTP_INC_STATS_USER(),
SNMP_INC_STATS64_USER(), SNMP_ADD_STATS64_USER(), TCP_ADD_STATS_USER(),
UDP_INC_STATS_USER(), UDP6_INC_STATS_USER(), and XFRM_INC_STATS_USER()

Following patches will rename __BH helpers to make clear their
usage is not tied to BH being disabled.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -194,10 +194,8 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 #define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
 #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)
 
 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);
 unsigned long snmp_fold_field(void __percpu *mib, int offt);

include/net/sctp/sctp.h

@@ -207,7 +207,6 @@ extern int sysctl_sctp_wmem[3];
 /* SCTP SNMP MIB stats handlers */
 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
 #define SCTP_INC_STATS_BH(net, field)   SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
-#define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
 
 /* sctp mib definitions */

include/net/snmp.h

@@ -126,9 +126,6 @@ struct linux_xfrm_mib {
 #define SNMP_INC_STATS_BH(mib, field)	\
 			__this_cpu_inc(mib->mibs[field])
 
-#define SNMP_INC_STATS_USER(mib, field)	\
-			this_cpu_inc(mib->mibs[field])
-
 #define SNMP_INC_STATS_ATOMIC_LONG(mib, field)	\
 			atomic_long_inc(&mib->mibs[field])
 
@@ -141,9 +138,6 @@ struct linux_xfrm_mib {
 #define SNMP_ADD_STATS_BH(mib, field, addend)	\
 			__this_cpu_add(mib->mibs[field], addend)
 
-#define SNMP_ADD_STATS_USER(mib, field, addend)	\
-			this_cpu_add(mib->mibs[field], addend)
-
 #define SNMP_ADD_STATS(mib, field, addend)	\
 			this_cpu_add(mib->mibs[field], addend)
 #define SNMP_UPD_PO_STATS(mib, basefield, addend)	\
@@ -170,18 +164,14 @@ struct linux_xfrm_mib {
 		u64_stats_update_end(&ptr->syncp);			\
 	} while (0)
 
-#define SNMP_ADD_STATS64_USER(mib, field, addend) 			\
+#define SNMP_ADD_STATS64(mib, field, addend) 			\
 	do {								\
-		local_bh_disable();					\
+		preempt_disable();					\
 		SNMP_ADD_STATS64_BH(mib, field, addend);		\
-		local_bh_enable();					\
+		preempt_enable();					\
 	} while (0)
 
-#define SNMP_ADD_STATS64(mib, field, addend)				\
-		SNMP_ADD_STATS64_USER(mib, field, addend)
-
 #define SNMP_INC_STATS64_BH(mib, field) SNMP_ADD_STATS64_BH(mib, field, 1)
-#define SNMP_INC_STATS64_USER(mib, field) SNMP_ADD_STATS64_USER(mib, field, 1)
 #define SNMP_INC_STATS64(mib, field) SNMP_ADD_STATS64(mib, field, 1)
 #define SNMP_UPD_PO_STATS64_BH(mib, basefield, addend)			\
 	do {								\
@@ -194,17 +184,15 @@ struct linux_xfrm_mib {
 	} while (0)
 #define SNMP_UPD_PO_STATS64(mib, basefield, addend)			\
 	do {								\
-		local_bh_disable();					\
+		preempt_disable();					\
 		SNMP_UPD_PO_STATS64_BH(mib, basefield, addend);		\
-		local_bh_enable();					\
+		preempt_enable();					\
 	} while (0)
 #else
 #define SNMP_INC_STATS64_BH(mib, field)		SNMP_INC_STATS_BH(mib, field)
-#define SNMP_INC_STATS64_USER(mib, field)	SNMP_INC_STATS_USER(mib, field)
 #define SNMP_INC_STATS64(mib, field)		SNMP_INC_STATS(mib, field)
 #define SNMP_DEC_STATS64(mib, field)		SNMP_DEC_STATS(mib, field)
 #define SNMP_ADD_STATS64_BH(mib, field, addend) SNMP_ADD_STATS_BH(mib, field, addend)
-#define SNMP_ADD_STATS64_USER(mib, field, addend) SNMP_ADD_STATS_USER(mib, field, addend)
 #define SNMP_ADD_STATS64(mib, field, addend)	SNMP_ADD_STATS(mib, field, addend)
 #define SNMP_UPD_PO_STATS64(mib, basefield, addend) SNMP_UPD_PO_STATS(mib, basefield, addend)
 #define SNMP_UPD_PO_STATS64_BH(mib, basefield, addend) SNMP_UPD_PO_STATS_BH(mib, basefield, addend)

include/net/tcp.h

@@ -334,7 +334,6 @@ extern struct proto tcp_prot;
 #define TCP_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.tcp_statistics, field)
 #define TCP_INC_STATS_BH(net, field)	SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field)
 #define TCP_DEC_STATS(net, field)	SNMP_DEC_STATS((net)->mib.tcp_statistics, field)
-#define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val)
 #define TCP_ADD_STATS(net, field, val)	SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val)
 
 void tcp_tasklet_init(void);
@@ -1298,10 +1297,10 @@ bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
 static inline void tcp_mib_init(struct net *net)
 {
 	/* See RFC 2012 */
-	TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1);
-	TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
-	TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
-	TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1);
+	TCP_ADD_STATS(net, TCP_MIB_RTOALGORITHM, 1);
+	TCP_ADD_STATS(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ);
+	TCP_ADD_STATS(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ);
+	TCP_ADD_STATS(net, TCP_MIB_MAXCONN, -1);
 }
 
 /* from STCP */

include/net/udp.h

@@ -289,9 +289,9 @@ struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
 /*
  * 	SNMP statistics for UDP and UDP-Lite
  */
-#define UDP_INC_STATS_USER(net, field, is_udplite)	      do { \
-	if (is_udplite) SNMP_INC_STATS_USER((net)->mib.udplite_statistics, field);       \
-	else		SNMP_INC_STATS_USER((net)->mib.udp_statistics, field);  }  while(0)
+#define UDP_INC_STATS(net, field, is_udplite)		      do { \
+	if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
+	else		SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
 #define UDP_INC_STATS_BH(net, field, is_udplite) 	      do { \
 	if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_statistics, field);         \
 	else		SNMP_INC_STATS_BH((net)->mib.udp_statistics, field);    }  while(0)
@@ -300,9 +300,9 @@ struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
 	if (is_udplite) SNMP_INC_STATS_BH((net)->mib.udplite_stats_in6, field);\
 	else		SNMP_INC_STATS_BH((net)->mib.udp_stats_in6, field);  \
 } while(0)
-#define UDP6_INC_STATS_USER(net, field, __lite)		    do { \
-	if (__lite) SNMP_INC_STATS_USER((net)->mib.udplite_stats_in6, field);  \
-	else	    SNMP_INC_STATS_USER((net)->mib.udp_stats_in6, field);      \
+#define UDP6_INC_STATS(net, field, __lite)		    do { \
+	if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);  \
+	else	    SNMP_INC_STATS((net)->mib.udp_stats_in6, field);      \
 } while(0)
 
 #if IS_ENABLED(CONFIG_IPV6)

include/net/xfrm.h

@@ -46,11 +46,9 @@
 #ifdef CONFIG_XFRM_STATISTICS
 #define XFRM_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.xfrm_statistics, field)
 #define XFRM_INC_STATS_BH(net, field)	SNMP_INC_STATS_BH((net)->mib.xfrm_statistics, field)
-#define XFRM_INC_STATS_USER(net, field)	SNMP_INC_STATS_USER((net)-mib.xfrm_statistics, field)
 #else
 #define XFRM_INC_STATS(net, field)	((void)(net))
 #define XFRM_INC_STATS_BH(net, field)	((void)(net))
-#define XFRM_INC_STATS_USER(net, field)	((void)(net))
 #endif
 
 

net/ipv4/tcp.c

@@ -1443,7 +1443,7 @@ static void tcp_prequeue_process(struct sock *sk)
 	struct sk_buff *skb;
 	struct tcp_sock *tp = tcp_sk(sk);
 
-	NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
+	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
 
 	/* RX process wants to run with disabled BHs, though it is not
 	 * necessary */
@@ -1777,7 +1777,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
 
 			chunk = len - tp->ucopy.len;
 			if (chunk != 0) {
-				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
+				NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMBACKLOG, chunk);
 				len -= chunk;
 				copied += chunk;
 			}
@@ -1789,7 +1789,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
 
 				chunk = len - tp->ucopy.len;
 				if (chunk != 0) {
-					NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
+					NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
 					len -= chunk;
 					copied += chunk;
 				}
@@ -1875,7 +1875,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
 			tcp_prequeue_process(sk);
 
 			if (copied > 0 && (chunk = len - tp->ucopy.len) != 0) {
-				NET_ADD_STATS_USER(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
+				NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPDIRECTCOPYFROMPREQUEUE, chunk);
 				len -= chunk;
 				copied += chunk;
 			}
@@ -2065,13 +2065,13 @@ void tcp_close(struct sock *sk, long timeout)
 		sk->sk_prot->disconnect(sk, 0);
 	} else if (data_was_unread) {
 		/* Unread data was tossed, zap the connection. */
-		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
 		tcp_set_state(sk, TCP_CLOSE);
 		tcp_send_active_reset(sk, sk->sk_allocation);
 	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
 		/* Check zero linger _after_ checking for unread data. */
 		sk->sk_prot->disconnect(sk, 0);
-		NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
 	} else if (tcp_close_state(sk)) {
 		/* We FIN if the application ate all the data before
 		 * zapping the connection.

net/ipv4/udp.c

@@ -882,12 +882,12 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
 	err = ip_send_skb(sock_net(sk), skb);
 	if (err) {
 		if (err == -ENOBUFS && !inet->recverr) {
-			UDP_INC_STATS_USER(sock_net(sk),
+			UDP_INC_STATS(sock_net(sk),
 				      UDP_MIB_SNDBUFERRORS, is_udplite);
 			err = 0;
 		}
 	} else
-		UDP_INC_STATS_USER(sock_net(sk),
+		UDP_INC_STATS(sock_net(sk),
 			      UDP_MIB_OUTDATAGRAMS, is_udplite);
 	return err;
 }
@@ -1157,7 +1157,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	 * seems like overkill.
 	 */
 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
-		UDP_INC_STATS_USER(sock_net(sk),
+		UDP_INC_STATS(sock_net(sk),
 			      UDP_MIB_SNDBUFERRORS, is_udplite);
 	}
 	return err;
@@ -1352,7 +1352,7 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 		trace_kfree_skb(skb, udp_recvmsg);
 		if (!peeked) {
 			atomic_inc(&sk->sk_drops);
-			UDP_INC_STATS_USER(sock_net(sk),
+			UDP_INC_STATS(sock_net(sk),
 				      UDP_MIB_INERRORS, is_udplite);
 		}
 		skb_free_datagram_locked(sk, skb);
@@ -1360,7 +1360,7 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 	}
 
 	if (!peeked)
-		UDP_INC_STATS_USER(sock_net(sk),
+		UDP_INC_STATS(sock_net(sk),
 			      UDP_MIB_INDATAGRAMS, is_udplite);
 
 	sock_recv_ts_and_drops(msg, sk, skb);
@@ -1386,8 +1386,8 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 csum_copy_err:
 	slow = lock_sock_fast(sk);
 	if (!skb_kill_datagram(sk, skb, flags)) {
-		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
-		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+		UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
+		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 	}
 	unlock_sock_fast(sk, slow);
 

net/ipv6/udp.c

@@ -423,12 +423,10 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		if (!peeked) {
 			atomic_inc(&sk->sk_drops);
 			if (is_udp4)
-				UDP_INC_STATS_USER(sock_net(sk),
-						   UDP_MIB_INERRORS,
+				UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
 					      is_udplite);
 			else
-				UDP6_INC_STATS_USER(sock_net(sk),
-						    UDP_MIB_INERRORS,
+				UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
 					       is_udplite);
 		}
 		skb_free_datagram_locked(sk, skb);
@@ -436,11 +434,11 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	}
 	if (!peeked) {
 		if (is_udp4)
-			UDP_INC_STATS_USER(sock_net(sk),
-					UDP_MIB_INDATAGRAMS, is_udplite);
+			UDP_INC_STATS(sock_net(sk), UDP_MIB_INDATAGRAMS,
+				      is_udplite);
 		else
-			UDP6_INC_STATS_USER(sock_net(sk),
-					UDP_MIB_INDATAGRAMS, is_udplite);
+			UDP6_INC_STATS(sock_net(sk), UDP_MIB_INDATAGRAMS,
+				       is_udplite);
 	}
 
 	sock_recv_ts_and_drops(msg, sk, skb);
@@ -487,14 +485,14 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	slow = lock_sock_fast(sk);
 	if (!skb_kill_datagram(sk, skb, flags)) {
 		if (is_udp4) {
-			UDP_INC_STATS_USER(sock_net(sk),
+			UDP_INC_STATS(sock_net(sk),
 				      UDP_MIB_CSUMERRORS, is_udplite);
-			UDP_INC_STATS_USER(sock_net(sk),
+			UDP_INC_STATS(sock_net(sk),
 				      UDP_MIB_INERRORS, is_udplite);
 		} else {
-			UDP6_INC_STATS_USER(sock_net(sk),
+			UDP6_INC_STATS(sock_net(sk),
 				       UDP_MIB_CSUMERRORS, is_udplite);
-			UDP6_INC_STATS_USER(sock_net(sk),
+			UDP6_INC_STATS(sock_net(sk),
 				       UDP_MIB_INERRORS, is_udplite);
 		}
 	}
@@ -1015,13 +1013,14 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6)
 	err = ip6_send_skb(skb);
 	if (err) {
 		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
-			UDP6_INC_STATS_USER(sock_net(sk),
+			UDP6_INC_STATS(sock_net(sk),
 				       UDP_MIB_SNDBUFERRORS, is_udplite);
 			err = 0;
 		}
-	} else
-		UDP6_INC_STATS_USER(sock_net(sk),
+	} else {
+		UDP6_INC_STATS(sock_net(sk),
 			       UDP_MIB_OUTDATAGRAMS, is_udplite);
+	}
 	return err;
 }
 
@@ -1342,7 +1341,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	 * seems like overkill.
 	 */
 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
-		UDP6_INC_STATS_USER(sock_net(sk),
+		UDP6_INC_STATS(sock_net(sk),
 			       UDP_MIB_SNDBUFERRORS, is_udplite);
 	}
 	return err;

net/sctp/chunk.c

@@ -239,7 +239,7 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
 	offset = 0;
 
 	if ((whole > 1) || (whole && over))
-		SCTP_INC_STATS_USER(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS);
+		SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS);
 
 	/* Create chunks for all the full sized DATA chunks. */
 	for (i = 0, len = first_len; i < whole; i++) {