net: Explicitly initialize u64_stats_sync structures for lockdep

In order to enable lockdep on seqcount/seqlock structures, we
must explicitly initialize any locks.

The u64_stats_sync structure, uses a seqcount, and thus we need
to introduce a u64_stats_init() function and use it to initialize
the structure.

This unfortunately adds a lot of fairly trivial initialization code
to a number of drivers. But the benefit of ensuring correctness makes
this worth while.

Because these changes are required for lockdep to be enabled, and the
changes are quite trivial, I've not yet split this patch out into 30-some
separate patches, as I figured it would be better to get the various
maintainers thoughts on how to best merge this change along with
the seqcount lockdep enablement.

Feedback would be appreciated!

Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jesse Gross <jesse@nicira.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mirko Lindner <mlindner@marvell.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Roger Luethi <rl@hellgate.ch>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Simon Horman <horms@verge.net.au>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Wensong Zhang <wensong@linux-vs.org>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1381186321-4906-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

5 files changed, 65 insertions, 0 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index cd3fb30..d62d589 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -281,10 +281,24 @@ static void addrconf_mod_dad_timer(struct inet6_ifaddr *ifp,
 
 static int snmp6_alloc_dev(struct inet6_dev *idev)
 {
+	int i;
+
 	if (snmp_mib_init((void __percpu **)idev->stats.ipv6,
 			  sizeof(struct ipstats_mib),
 			  __alignof__(struct ipstats_mib)) < 0)
 		goto err_ip;
+
+	for_each_possible_cpu(i) {
+		struct ipstats_mib *addrconf_stats;
+		addrconf_stats = per_cpu_ptr(idev->stats.ipv6[0], i);
+		u64_stats_init(&addrconf_stats->syncp);
+#if SNMP_ARRAY_SZ == 2
+		addrconf_stats = per_cpu_ptr(idev->stats.ipv6[1], i);
+		u64_stats_init(&addrconf_stats->syncp);
+#endif
+	}
+
+
 	idev->stats.icmpv6dev = kzalloc(sizeof(struct icmpv6_mib_device),
 					GFP_KERNEL);
 	if (!idev->stats.icmpv6dev)
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 7c96100..a8f8559 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -719,6 +719,8 @@ static void ipv6_packet_cleanup(void)
 
 static int __net_init ipv6_init_mibs(struct net *net)
 {
+	int i;
+
 	if (snmp_mib_init((void __percpu **)net->mib.udp_stats_in6,
 			  sizeof(struct udp_mib),
 			  __alignof__(struct udp_mib)) < 0)
@@ -731,6 +733,18 @@ static int __net_init ipv6_init_mibs(struct net *net)
 			  sizeof(struct ipstats_mib),
 			  __alignof__(struct ipstats_mib)) < 0)
 		goto err_ip_mib;
+
+	for_each_possible_cpu(i) {
+		struct ipstats_mib *af_inet6_stats;
+		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics[0], i);
+		u64_stats_init(&af_inet6_stats->syncp);
+#if SNMP_ARRAY_SZ == 2
+		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics[1], i);
+		u64_stats_init(&af_inet6_stats->syncp);
+#endif
+	}
+
+
 	if (snmp_mib_init((void __percpu **)net->mib.icmpv6_statistics,
 			  sizeof(struct icmpv6_mib),
 			  __alignof__(struct icmpv6_mib)) < 0)
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index bf4a9a0..8acb286 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1252,6 +1252,7 @@ static void ip6gre_tunnel_setup(struct net_device *dev)
 static int ip6gre_tunnel_init(struct net_device *dev)
 {
 	struct ip6_tnl *tunnel;
+	int i;
 
 	tunnel = netdev_priv(dev);
 
@@ -1269,6 +1270,13 @@ static int ip6gre_tunnel_init(struct net_device *dev)
 	if (!dev->tstats)
 		return -ENOMEM;
 
+	for_each_possible_cpu(i) {
+		struct pcpu_tstats *ip6gre_tunnel_stats;
+		ip6gre_tunnel_stats = per_cpu_ptr(dev->tstats, i);
+		u64_stats_init(&ip6gre_tunnel_stats->syncp);
+	}
+
+
 	return 0;
 }
 
@@ -1449,6 +1457,7 @@ static void ip6gre_netlink_parms(struct nlattr *data[],
 static int ip6gre_tap_init(struct net_device *dev)
 {
 	struct ip6_tnl *tunnel;
+	int i;
 
 	tunnel = netdev_priv(dev);
 
@@ -1462,6 +1471,12 @@ static int ip6gre_tap_init(struct net_device *dev)
 	if (!dev->tstats)
 		return -ENOMEM;
 
+	for_each_possible_cpu(i) {
+		struct pcpu_tstats *ip6gre_tap_stats;
+		ip6gre_tap_stats = per_cpu_ptr(dev->tstats, i);
+		u64_stats_init(&ip6gre_tap_stats->syncp);
+	}
+
 	return 0;
 }
 
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 583b77e..df1fa58 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1494,12 +1494,19 @@ static inline int
 ip6_tnl_dev_init_gen(struct net_device *dev)
 {
 	struct ip6_tnl *t = netdev_priv(dev);
+	int i;
 
 	t->dev = dev;
 	t->net = dev_net(dev);
 	dev->tstats = alloc_percpu(struct pcpu_tstats);
 	if (!dev->tstats)
 		return -ENOMEM;
+
+	for_each_possible_cpu(i) {
+		struct pcpu_tstats *ip6_tnl_stats;
+		ip6_tnl_stats = per_cpu_ptr(dev->tstats, i);
+		u64_stats_init(&ip6_tnl_stats->syncp);
+	}
 	return 0;
 }
 
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 1926945..365dc54 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1310,6 +1310,7 @@ static void ipip6_tunnel_setup(struct net_device *dev)
 static int ipip6_tunnel_init(struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	int i;
 
 	tunnel->dev = dev;
 	tunnel->net = dev_net(dev);
@@ -1322,6 +1323,12 @@ static int ipip6_tunnel_init(struct net_device *dev)
 	if (!dev->tstats)
 		return -ENOMEM;
 
+	for_each_possible_cpu(i) {
+		struct pcpu_tstats *ipip6_tunnel_stats;
+		ipip6_tunnel_stats = per_cpu_ptr(dev->tstats, i);
+		u64_stats_init(&ipip6_tunnel_stats->syncp);
+	}
+
 	return 0;
 }
 
@@ -1331,6 +1338,7 @@ static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
 	struct iphdr *iph = &tunnel->parms.iph;
 	struct net *net = dev_net(dev);
 	struct sit_net *sitn = net_generic(net, sit_net_id);
+	int i;
 
 	tunnel->dev = dev;
 	tunnel->net = dev_net(dev);
@@ -1344,6 +1352,13 @@ static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
 	dev->tstats = alloc_percpu(struct pcpu_tstats);
 	if (!dev->tstats)
 		return -ENOMEM;
+
+	for_each_possible_cpu(i) {
+		struct pcpu_tstats *ipip6_fb_stats;
+		ipip6_fb_stats = per_cpu_ptr(dev->tstats, i);
+		u64_stats_init(&ipip6_fb_stats->syncp);
+	}
+
 	dev_hold(dev);
 	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
 	return 0;