[NET]: Add some acquires/releases sparse annotations.

Add __acquires() and __releases() annotations to suppress some sparse
warnings.

example of warnings :

net/ipv4/udp.c:1555:14: warning: context imbalance in 'udp_seq_start' - wrong
count at exit
net/ipv4/udp.c:1571:13: warning: context imbalance in 'udp_seq_stop' -
unexpected unlock
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2368,6 +2368,7 @@ static int dev_ifconf(struct net *net, char __user *arg)
  *	in detail.
  */
 void *dev_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(dev_base_lock)
 {
 	struct net *net = seq_file_net(seq);
 	loff_t off;
@@ -2394,6 +2395,7 @@ void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 void dev_seq_stop(struct seq_file *seq, void *v)
+	__releases(dev_base_lock)
 {
 	read_unlock(&dev_base_lock);
 }

net/core/dev_mcast.c

@@ -186,6 +186,7 @@ EXPORT_SYMBOL(dev_mc_unsync);
 
 #ifdef CONFIG_PROC_FS
 static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(dev_base_lock)
 {
 	struct net *net = seq_file_net(seq);
 	struct net_device *dev;
@@ -206,6 +207,7 @@ static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void dev_mc_seq_stop(struct seq_file *seq, void *v)
+	__releases(dev_base_lock)
 {
 	read_unlock(&dev_base_lock);
 }

net/core/gen_stats.c

@@ -55,6 +55,7 @@ gnet_stats_copy(struct gnet_dump *d, int type, void *buf, int size)
 int
 gnet_stats_start_copy_compat(struct sk_buff *skb, int type, int tc_stats_type,
 	int xstats_type, spinlock_t *lock, struct gnet_dump *d)
+	__acquires(lock)
 {
 	memset(d, 0, sizeof(*d));
 

net/core/neighbour.c

@@ -2313,6 +2313,7 @@ static void *neigh_get_idx_any(struct seq_file *seq, loff_t *pos)
 }
 
 void *neigh_seq_start(struct seq_file *seq, loff_t *pos, struct neigh_table *tbl, unsigned int neigh_seq_flags)
+	__acquires(tbl->lock)
 {
 	struct neigh_seq_state *state = seq->private;
 	loff_t pos_minus_one;
@@ -2356,6 +2357,7 @@ void *neigh_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 EXPORT_SYMBOL(neigh_seq_next);
 
 void neigh_seq_stop(struct seq_file *seq, void *v)
+	__releases(tbl->lock)
 {
 	struct neigh_seq_state *state = seq->private;
 	struct neigh_table *tbl = state->tbl;

net/core/sock.c

@@ -2025,6 +2025,7 @@ EXPORT_SYMBOL(proto_unregister);
 
 #ifdef CONFIG_PROC_FS
 static void *proto_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(proto_list_lock)
 {
 	read_lock(&proto_list_lock);
 	return seq_list_start_head(&proto_list, *pos);
@@ -2036,6 +2037,7 @@ static void *proto_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void proto_seq_stop(struct seq_file *seq, void *v)
+	__releases(proto_list_lock)
 {
 	read_unlock(&proto_list_lock);
 }

net/ipv4/fib_hash.c

@@ -936,6 +936,7 @@ static struct fib_alias *fib_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *fib_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(fib_hash_lock)
 {
 	void *v = NULL;
 
@@ -952,6 +953,7 @@ static void *fib_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void fib_seq_stop(struct seq_file *seq, void *v)
+	__releases(fib_hash_lock)
 {
 	read_unlock(&fib_hash_lock);
 }

net/ipv4/inet_hashtables.c

@@ -96,6 +96,7 @@ EXPORT_SYMBOL(inet_put_port);
  * exclusive lock release). It should be ifdefed really.
  */
 void inet_listen_wlock(struct inet_hashinfo *hashinfo)
+	__acquires(hashinfo->lhash_lock)
 {
 	write_lock(&hashinfo->lhash_lock);
 

net/ipv4/udp.c

@@ -1550,6 +1550,7 @@ static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(udp_hash_lock)
 {
 	read_lock(&udp_hash_lock);
 	return *pos ? udp_get_idx(seq, *pos-1) : (void *)1;
@@ -1569,6 +1570,7 @@ static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void udp_seq_stop(struct seq_file *seq, void *v)
+	__releases(udp_hash_lock)
 {
 	read_unlock(&udp_hash_lock);
 }

net/ipv6/anycast.c

@@ -504,6 +504,7 @@ static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(dev_base_lock)
 {
 	read_lock(&dev_base_lock);
 	return ac6_get_idx(seq, *pos);
@@ -518,6 +519,7 @@ static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void ac6_seq_stop(struct seq_file *seq, void *v)
+	__releases(dev_base_lock)
 {
 	struct ac6_iter_state *state = ac6_seq_private(seq);
 	if (likely(state->idev != NULL)) {

net/ipv6/ip6_flowlabel.c

@@ -629,6 +629,7 @@ static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(ip6_fl_lock)
 {
 	read_lock_bh(&ip6_fl_lock);
 	return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
@@ -647,6 +648,7 @@ static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
+	__releases(ip6_fl_lock)
 {
 	read_unlock_bh(&ip6_fl_lock);
 }

net/ipv6/mcast.c

@@ -2373,6 +2373,7 @@ static struct ifmcaddr6 *igmp6_mc_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *igmp6_mc_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(dev_base_lock)
 {
 	read_lock(&dev_base_lock);
 	return igmp6_mc_get_idx(seq, *pos);
@@ -2387,6 +2388,7 @@ static void *igmp6_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void igmp6_mc_seq_stop(struct seq_file *seq, void *v)
+	__releases(dev_base_lock)
 {
 	struct igmp6_mc_iter_state *state = igmp6_mc_seq_private(seq);
 	if (likely(state->idev != NULL)) {
@@ -2516,6 +2518,7 @@ static struct ip6_sf_list *igmp6_mcf_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *igmp6_mcf_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(dev_base_lock)
 {
 	read_lock(&dev_base_lock);
 	return *pos ? igmp6_mcf_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
@@ -2533,6 +2536,7 @@ static void *igmp6_mcf_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void igmp6_mcf_seq_stop(struct seq_file *seq, void *v)
+	__releases(dev_base_lock)
 {
 	struct igmp6_mcf_iter_state *state = igmp6_mcf_seq_private(seq);
 	if (likely(state->im != NULL)) {

net/netlink/af_netlink.c

@@ -171,6 +171,7 @@ static void netlink_sock_destruct(struct sock *sk)
  */
 
 static void netlink_table_grab(void)
+	__acquires(nl_table_lock)
 {
 	write_lock_irq(&nl_table_lock);
 
@@ -193,6 +194,7 @@ static void netlink_table_grab(void)
 }
 
 static inline void netlink_table_ungrab(void)
+	__releases(nl_table_lock)
 {
 	write_unlock_irq(&nl_table_lock);
 	wake_up(&nl_table_wait);
@@ -1728,6 +1730,7 @@ static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(nl_table_lock)
 {
 	read_lock(&nl_table_lock);
 	return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
@@ -1776,6 +1779,7 @@ static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void netlink_seq_stop(struct seq_file *seq, void *v)
+	__releases(nl_table_lock)
 {
 	read_unlock(&nl_table_lock);
 }

net/sched/sch_generic.c

@@ -40,12 +40,16 @@
  */
 
 void qdisc_lock_tree(struct net_device *dev)
+	__acquires(dev->queue_lock)
+	__acquires(dev->ingress_lock)
 {
 	spin_lock_bh(&dev->queue_lock);
 	spin_lock(&dev->ingress_lock);
 }
 
 void qdisc_unlock_tree(struct net_device *dev)
+	__releases(dev->ingress_lock)
+	__releases(dev->queue_lock)
 {
 	spin_unlock(&dev->ingress_lock);
 	spin_unlock_bh(&dev->queue_lock);

net/sunrpc/cache.c

@@ -1127,6 +1127,7 @@ struct handle {
 };
 
 static void *c_start(struct seq_file *m, loff_t *pos)
+	__acquires(cd->hash_lock)
 {
 	loff_t n = *pos;
 	unsigned hash, entry;
@@ -1183,6 +1184,7 @@ static void *c_next(struct seq_file *m, void *p, loff_t *pos)
 }
 
 static void c_stop(struct seq_file *m, void *p)
+	__releases(cd->hash_lock)
 {
 	struct cache_detail *cd = ((struct handle*)m->private)->cd;
 	read_unlock(&cd->hash_lock);

net/unix/af_unix.c

@@ -2033,6 +2033,7 @@ static struct sock *unix_seq_idx(struct unix_iter_state *iter, loff_t pos)
 
 
 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(unix_table_lock)
 {
 	struct unix_iter_state *iter = seq->private;
 	spin_lock(&unix_table_lock);
@@ -2055,6 +2056,7 @@ static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 }
 
 static void unix_seq_stop(struct seq_file *seq, void *v)
+	__releases(unix_table_lock)
 {
 	spin_unlock(&unix_table_lock);
 }

net/xfrm/xfrm_state.c

@@ -211,6 +211,7 @@ static struct xfrm_state_afinfo *xfrm_state_lock_afinfo(unsigned int family)
 }
 
 static void xfrm_state_unlock_afinfo(struct xfrm_state_afinfo *afinfo)
+	__releases(xfrm_state_afinfo_lock)
 {
 	write_unlock_bh(&xfrm_state_afinfo_lock);
 }
@@ -1909,6 +1910,7 @@ static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
 }
 
 static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
+	__releases(xfrm_state_afinfo_lock)
 {
 	read_unlock(&xfrm_state_afinfo_lock);
 }