net/packet: convert po->running to an atomic flag

Instead of consuming 32 bits for po->running, use
one available bit in po->flags.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -340,14 +340,14 @@ static void __register_prot_hook(struct sock *sk)
 {
 	struct packet_sock *po = pkt_sk(sk);
 
-	if (!po->running) {
+	if (!packet_sock_flag(po, PACKET_SOCK_RUNNING)) {
 		if (po->fanout)
 			__fanout_link(sk, po);
 		else
 			dev_add_pack(&po->prot_hook);
 
 		sock_hold(sk);
-		po->running = 1;
+		packet_sock_flag_set(po, PACKET_SOCK_RUNNING, 1);
 	}
 }
 
@@ -369,7 +369,7 @@ static void __unregister_prot_hook(struct sock *sk, bool sync)
 
 	lockdep_assert_held_once(&po->bind_lock);
 
-	po->running = 0;
+	packet_sock_flag_set(po, PACKET_SOCK_RUNNING, 0);
 
 	if (po->fanout)
 		__fanout_unlink(sk, po);
@@ -389,7 +389,7 @@ static void unregister_prot_hook(struct sock *sk, bool sync)
 {
 	struct packet_sock *po = pkt_sk(sk);
 
-	if (po->running)
+	if (packet_sock_flag(po, PACKET_SOCK_RUNNING))
 		__unregister_prot_hook(sk, sync);
 }
 
@@ -1782,7 +1782,7 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)
 	err = -EINVAL;
 
 	spin_lock(&po->bind_lock);
-	if (po->running &&
+	if (packet_sock_flag(po, PACKET_SOCK_RUNNING) &&
 	    match->type == type &&
 	    match->prot_hook.type == po->prot_hook.type &&
 	    match->prot_hook.dev == po->prot_hook.dev) {
@@ -3222,7 +3222,7 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex,
 
 	if (need_rehook) {
 		dev_hold(dev);
-		if (po->running) {
+		if (packet_sock_flag(po, PACKET_SOCK_RUNNING)) {
 			rcu_read_unlock();
 			/* prevents packet_notifier() from calling
 			 * register_prot_hook()
@@ -3235,7 +3235,7 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex,
 								 dev->ifindex);
 		}
 
-		BUG_ON(po->running);
+		BUG_ON(packet_sock_flag(po, PACKET_SOCK_RUNNING));
 		WRITE_ONCE(po->num, proto);
 		po->prot_hook.type = proto;
 
@@ -4159,7 +4159,7 @@ static int packet_notifier(struct notifier_block *this,
 		case NETDEV_DOWN:
 			if (dev->ifindex == po->ifindex) {
 				spin_lock(&po->bind_lock);
-				if (po->running) {
+				if (packet_sock_flag(po, PACKET_SOCK_RUNNING)) {
 					__unregister_prot_hook(sk, false);
 					sk->sk_err = ENETDOWN;
 					if (!sock_flag(sk, SOCK_DEAD))
@@ -4470,7 +4470,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 
 	/* Detach socket from network */
 	spin_lock(&po->bind_lock);
-	was_running = po->running;
+	was_running = packet_sock_flag(po, PACKET_SOCK_RUNNING);
 	num = po->num;
 	if (was_running) {
 		WRITE_ONCE(po->num, 0);
@@ -4681,7 +4681,7 @@ static int packet_seq_show(struct seq_file *seq, void *v)
 			   s->sk_type,
 			   ntohs(READ_ONCE(po->num)),
 			   READ_ONCE(po->ifindex),
-			   po->running,
+			   packet_sock_flag(po, PACKET_SOCK_RUNNING),
 			   atomic_read(&s->sk_rmem_alloc),
 			   from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)),
 			   sock_i_ino(s));

net/packet/diag.c

@@ -21,7 +21,7 @@ static int pdiag_put_info(const struct packet_sock *po, struct sk_buff *nlskb)
 	pinfo.pdi_tstamp = READ_ONCE(po->tp_tstamp);
 
 	pinfo.pdi_flags = 0;
-	if (po->running)
+	if (packet_sock_flag(po, PACKET_SOCK_RUNNING))
 		pinfo.pdi_flags |= PDI_RUNNING;
 	if (packet_sock_flag(po, PACKET_SOCK_AUXDATA))
 		pinfo.pdi_flags |= PDI_AUXDATA;

net/packet/internal.h

@@ -117,7 +117,6 @@ struct packet_sock {
 	spinlock_t		bind_lock;
 	struct mutex		pg_vec_lock;
 	unsigned long		flags;
-	unsigned int		running;	/* bind_lock must be held */
 	int			pressure;
 	int			ifindex;	/* bound device		*/
 	__be16			num;
@@ -146,6 +145,7 @@ enum packet_sock_flags {
 	PACKET_SOCK_TX_HAS_OFF,
 	PACKET_SOCK_TP_LOSS,
 	PACKET_SOCK_HAS_VNET_HDR,
+	PACKET_SOCK_RUNNING,
 };
 
 static inline void packet_sock_flag_set(struct packet_sock *po,