udp: introduce udp->udp_flags

[ Upstream commit 81b36803ac139827538ac5ce4028e750a3c53f53 ]

According to syzbot, it is time to use proper atomic flags
for various UDP flags.

Add udp_flags field, and convert udp->corkflag to first
bit in it.

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>
Stable-dep-of: a0002127cd74 ("udp: move udp->no_check6_tx to udp->udp_flags")
Signed-off-by: Sasha Levin <[email protected]>
diff --git a/include/linux/udp.h b/include/linux/udp.h
index e96da41..10b56b8 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -30,14 +30,20 @@ static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
 	return (num + net_hash_mix(net)) & mask;
 }
 
+enum {
+	UDP_FLAGS_CORK,		/* Cork is required */
+};
+
 struct udp_sock {
 	/* inet_sock has to be the first member */
 	struct inet_sock inet;
 #define udp_port_hash		inet.sk.__sk_common.skc_u16hashes[0]
 #define udp_portaddr_hash	inet.sk.__sk_common.skc_u16hashes[1]
 #define udp_portaddr_node	inet.sk.__sk_common.skc_portaddr_node
+
+	unsigned long	 udp_flags;
+
 	int		 pending;	/* Any pending frames ? */
-	unsigned int	 corkflag;	/* Cork is required */
 	__u8		 encap_type;	/* Is this an Encapsulation socket? */
 	unsigned char	 no_check6_tx:1,/* Send zero UDP6 checksums on TX? */
 			 no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
@@ -49,6 +55,11 @@ struct udp_sock {
 			 gro_enabled:1,	/* Request GRO aggregation */
 			 accept_udp_l4:1,
 			 accept_udp_fraglist:1;
+/* indicator bits used by pcflag: */
+#define UDPLITE_BIT      0x1  		/* set by udplite proto init function */
+#define UDPLITE_SEND_CC  0x2  		/* set via udplite setsockopt         */
+#define UDPLITE_RECV_CC  0x4		/* set via udplite setsocktopt        */
+	__u8		 pcflag;        /* marks socket as UDP-Lite if > 0    */
 	/*
 	 * Following member retains the information to create a UDP header
 	 * when the socket is uncorked.
@@ -60,12 +71,6 @@ struct udp_sock {
 	 */
 	__u16		 pcslen;
 	__u16		 pcrlen;
-/* indicator bits used by pcflag: */
-#define UDPLITE_BIT      0x1  		/* set by udplite proto init function */
-#define UDPLITE_SEND_CC  0x2  		/* set via udplite setsockopt         */
-#define UDPLITE_RECV_CC  0x4		/* set via udplite setsocktopt        */
-	__u8		 pcflag;        /* marks socket as UDP-Lite if > 0    */
-	__u8		 unused[3];
 	/*
 	 * For encapsulation sockets.
 	 */
@@ -89,6 +94,15 @@ struct udp_sock {
 	int		forward_deficit;
 };
 
+#define udp_test_bit(nr, sk)			\
+	test_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
+#define udp_set_bit(nr, sk)			\
+	set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
+#define udp_clear_bit(nr, sk)			\
+	clear_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
+#define udp_assign_bit(nr, sk, val)		\
+	assign_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags, val)
+
 #define UDP_MAX_SEGMENTS	(1 << 6UL)
 
 static inline struct udp_sock *udp_sk(const struct sock *sk)