Merge branch 'inet-data-races'

Eric Dumazet says:

====================
inet: socket lock and data-races avoidance

In this series, I converted 20 bits in "struct inet_sock" and made
them truly atomic.

This allows to implement many IP_ socket options in a lockless
fashion (no need to acquire socket lock), and fixes data-races
that were showing up in various KCSAN reports.

I also took care of IP_TTL/IP_MINTTL, but left few other options
for another series.

v4: Rebased after recent mptcp changes.
  Added Reviewed-by: tags from Simon (thanks !)

v3: fixed patch 7, feedback from build bot about ipvs set_mcast_loop()

v2: addressed a feedback from a build bot in patch 9 by removing
 unused issk variable in mptcp_setsockopt_sol_ip_set_transparent()
 Added Acked-by: tags from Soheil (thanks !)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 68 insertions, 35 deletions

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index be3c858a2ebb..5d2fcc137b88 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -342,9 +342,9 @@ static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 	return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
 }
 
-static inline bool inet_csk_has_ulp(struct sock *sk)
+static inline bool inet_csk_has_ulp(const struct sock *sk)
 {
-	return inet_sk(sk)->is_icsk && !!inet_csk(sk)->icsk_ulp_ops;
+	return inet_test_bit(IS_ICSK, sk) && !!inet_csk(sk)->icsk_ulp_ops;
 }
 
 #endif /* _INET_CONNECTION_SOCK_H */
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 0bb32bfc6183..acbb93d7607a 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -194,13 +194,13 @@ struct rtable;
  * @inet_rcv_saddr - Bound local IPv4 addr
  * @inet_dport - Destination port
  * @inet_num - Local port
+ * @inet_flags - various atomic flags
  * @inet_saddr - Sending source
  * @uc_ttl - Unicast TTL
  * @inet_sport - Source port
  * @inet_id - ID counter for DF pkts
  * @tos - TOS
  * @mc_ttl - Multicasting TTL
- * @is_icsk - is this an inet_connection_sock?
  * @uc_index - Unicast outgoing device index
  * @mc_index - Multicast device index
  * @mc_list - Group array
@@ -218,57 +218,88 @@ struct inet_sock {
 #define inet_dport		sk.__sk_common.skc_dport
 #define inet_num		sk.__sk_common.skc_num
 
+	unsigned long		inet_flags;
 	__be32			inet_saddr;
 	__s16			uc_ttl;
-	__u16			cmsg_flags;
-	struct ip_options_rcu __rcu	*inet_opt;
 	__be16			inet_sport;
+	struct ip_options_rcu __rcu	*inet_opt;
 	__u16			inet_id;
 
 	__u8			tos;
 	__u8			min_ttl;
 	__u8			mc_ttl;
 	__u8			pmtudisc;
-	__u8			recverr:1,
-				is_icsk:1,
-				freebind:1,
-				hdrincl:1,
-				mc_loop:1,
-				transparent:1,
-				mc_all:1,
-				nodefrag:1;
-	__u8			bind_address_no_port:1,
-				recverr_rfc4884:1,
-				defer_connect:1; /* Indicates that fastopen_connect is set
-						  * and cookie exists so we defer connect
-						  * until first data frame is written
-						  */
 	__u8			rcv_tos;
 	__u8			convert_csum;
 	int			uc_index;
 	int			mc_index;
 	__be32			mc_addr;
-	struct ip_mc_socklist __rcu	*mc_list;
-	struct inet_cork_full	cork;
 	struct {
 		__u16 lo;
 		__u16 hi;
 	}			local_port_range;
+
+	struct ip_mc_socklist __rcu	*mc_list;
+	struct inet_cork_full	cork;
 };
 
 #define IPCORK_OPT	1	/* ip-options has been held in ipcork.opt */
 #define IPCORK_ALLFRAG	2	/* always fragment (for ipv6 for now) */
 
+enum {
+	INET_FLAGS_PKTINFO	= 0,
+	INET_FLAGS_TTL		= 1,
+	INET_FLAGS_TOS		= 2,
+	INET_FLAGS_RECVOPTS	= 3,
+	INET_FLAGS_RETOPTS	= 4,
+	INET_FLAGS_PASSSEC	= 5,
+	INET_FLAGS_ORIGDSTADDR	= 6,
+	INET_FLAGS_CHECKSUM	= 7,
+	INET_FLAGS_RECVFRAGSIZE	= 8,
+
+	INET_FLAGS_RECVERR	= 9,
+	INET_FLAGS_RECVERR_RFC4884 = 10,
+	INET_FLAGS_FREEBIND	= 11,
+	INET_FLAGS_HDRINCL	= 12,
+	INET_FLAGS_MC_LOOP	= 13,
+	INET_FLAGS_MC_ALL	= 14,
+	INET_FLAGS_TRANSPARENT	= 15,
+	INET_FLAGS_IS_ICSK	= 16,
+	INET_FLAGS_NODEFRAG	= 17,
+	INET_FLAGS_BIND_ADDRESS_NO_PORT = 18,
+	INET_FLAGS_DEFER_CONNECT = 19,
+};
+
 /* cmsg flags for inet */
-#define IP_CMSG_PKTINFO		BIT(0)
-#define IP_CMSG_TTL		BIT(1)
-#define IP_CMSG_TOS		BIT(2)
-#define IP_CMSG_RECVOPTS	BIT(3)
-#define IP_CMSG_RETOPTS		BIT(4)
-#define IP_CMSG_PASSSEC		BIT(5)
-#define IP_CMSG_ORIGDSTADDR	BIT(6)
-#define IP_CMSG_CHECKSUM	BIT(7)
-#define IP_CMSG_RECVFRAGSIZE	BIT(8)
+#define IP_CMSG_PKTINFO		BIT(INET_FLAGS_PKTINFO)
+#define IP_CMSG_TTL		BIT(INET_FLAGS_TTL)
+#define IP_CMSG_TOS		BIT(INET_FLAGS_TOS)
+#define IP_CMSG_RECVOPTS	BIT(INET_FLAGS_RECVOPTS)
+#define IP_CMSG_RETOPTS		BIT(INET_FLAGS_RETOPTS)
+#define IP_CMSG_PASSSEC		BIT(INET_FLAGS_PASSSEC)
+#define IP_CMSG_ORIGDSTADDR	BIT(INET_FLAGS_ORIGDSTADDR)
+#define IP_CMSG_CHECKSUM	BIT(INET_FLAGS_CHECKSUM)
+#define IP_CMSG_RECVFRAGSIZE	BIT(INET_FLAGS_RECVFRAGSIZE)
+
+#define IP_CMSG_ALL	(IP_CMSG_PKTINFO | IP_CMSG_TTL |		\
+			 IP_CMSG_TOS | IP_CMSG_RECVOPTS |		\
+			 IP_CMSG_RETOPTS | IP_CMSG_PASSSEC |		\
+			 IP_CMSG_ORIGDSTADDR | IP_CMSG_CHECKSUM |	\
+			 IP_CMSG_RECVFRAGSIZE)
+
+static inline unsigned long inet_cmsg_flags(const struct inet_sock *inet)
+{
+	return READ_ONCE(inet->inet_flags) & IP_CMSG_ALL;
+}
+
+#define inet_test_bit(nr, sk)			\
+	test_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags)
+#define inet_set_bit(nr, sk)			\
+	set_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags)
+#define inet_clear_bit(nr, sk)			\
+	clear_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags)
+#define inet_assign_bit(nr, sk, val)		\
+	assign_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags, val)
 
 static inline bool sk_is_inet(struct sock *sk)
 {
@@ -363,7 +394,7 @@ static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
 {
 	__u8 flags = 0;
 
-	if (inet_sk(sk)->transparent || inet_sk(sk)->hdrincl)
+	if (inet_test_bit(TRANSPARENT, sk) || inet_test_bit(HDRINCL, sk))
 		flags |= FLOWI_FLAG_ANYSRC;
 	return flags;
 }
@@ -389,7 +420,8 @@ static inline bool inet_can_nonlocal_bind(struct net *net,
 					  struct inet_sock *inet)
 {
 	return READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind) ||
-		inet->freebind || inet->transparent;
+		test_bit(INET_FLAGS_FREEBIND, &inet->inet_flags) ||
+		test_bit(INET_FLAGS_TRANSPARENT, &inet->inet_flags);
 }
 
 static inline bool inet_addr_valid_or_nonlocal(struct net *net,
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 22643ffc2df8..d40d8238d4c2 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -937,7 +937,8 @@ static inline bool ipv6_can_nonlocal_bind(struct net *net,
 					  struct inet_sock *inet)
 {
 	return net->ipv6.sysctl.ip_nonlocal_bind ||
-		inet->freebind || inet->transparent;
+		test_bit(INET_FLAGS_FREEBIND, &inet->inet_flags) ||
+		test_bit(INET_FLAGS_TRANSPARENT, &inet->inet_flags);
 }
 
 /* Sysctl settings for net ipv6.auto_flowlabels */
diff --git a/include/net/route.h b/include/net/route.h
index d9ca98d2366f..51a45b1887b5 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -298,7 +298,7 @@ static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
 {
 	__u8 flow_flags = 0;
 
-	if (inet_sk(sk)->transparent)
+	if (inet_test_bit(TRANSPARENT, sk))
 		flow_flags |= FLOWI_FLAG_ANYSRC;
 
 	flowi4_init_output(fl4, oif, READ_ONCE(sk->sk_mark), ip_sock_rt_tos(sk),
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 6d77c08d83b7..07b21d9a9620 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2031,7 +2031,7 @@ static inline bool inet_sk_transparent(const struct sock *sk)
 	case TCP_NEW_SYN_RECV:
 		return inet_rsk(inet_reqsk(sk))->no_srccheck;
 	}
-	return inet_sk(sk)->transparent;
+	return inet_test_bit(TRANSPARENT, sk);
 }
 
 /* Determines whether this is a thin stream (which may suffer from