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>

1 files changed, 22 insertions, 3 deletions

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index a3df9bddc4f7..3825725907f6 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -842,7 +842,7 @@ ip_vs_new_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest,
 	       struct ip_vs_dest **dest_p)
 {
 	struct ip_vs_dest *dest;
-	unsigned int atype;
+	unsigned int atype, i;
 
 	EnterFunction(2);
 
@@ -869,6 +869,12 @@ ip_vs_new_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest,
 	if (!dest->stats.cpustats)
 		goto err_alloc;
 
+	for_each_possible_cpu(i) {
+		struct ip_vs_cpu_stats *ip_vs_dest_stats;
+		ip_vs_dest_stats = per_cpu_ptr(dest->stats.cpustats, i);
+		u64_stats_init(&ip_vs_dest_stats->syncp);
+	}
+
 	dest->af = svc->af;
 	dest->protocol = svc->protocol;
 	dest->vaddr = svc->addr;
@@ -1134,7 +1140,7 @@ static int
 ip_vs_add_service(struct net *net, struct ip_vs_service_user_kern *u,
 		  struct ip_vs_service **svc_p)
 {
-	int ret = 0;
+	int ret = 0, i;
 	struct ip_vs_scheduler *sched = NULL;
 	struct ip_vs_pe *pe = NULL;
 	struct ip_vs_service *svc = NULL;
@@ -1184,6 +1190,13 @@ ip_vs_add_service(struct net *net, struct ip_vs_service_user_kern *u,
 		goto out_err;
 	}
 
+	for_each_possible_cpu(i) {
+		struct ip_vs_cpu_stats *ip_vs_stats;
+		ip_vs_stats = per_cpu_ptr(svc->stats.cpustats, i);
+		u64_stats_init(&ip_vs_stats->syncp);
+	}
+
+
 	/* I'm the first user of the service */
 	atomic_set(&svc->refcnt, 0);
 
@@ -3780,7 +3793,7 @@ static struct notifier_block ip_vs_dst_notifier = {
 
 int __net_init ip_vs_control_net_init(struct net *net)
 {
-	int idx;
+	int i, idx;
 	struct netns_ipvs *ipvs = net_ipvs(net);
 
 	/* Initialize rs_table */
@@ -3799,6 +3812,12 @@ int __net_init ip_vs_control_net_init(struct net *net)
 	if (!ipvs->tot_stats.cpustats)
 		return -ENOMEM;
 
+	for_each_possible_cpu(i) {
+		struct ip_vs_cpu_stats *ipvs_tot_stats;
+		ipvs_tot_stats = per_cpu_ptr(ipvs->tot_stats.cpustats, i);
+		u64_stats_init(&ipvs_tot_stats->syncp);
+	}
+
 	spin_lock_init(&ipvs->tot_stats.lock);
 
 	proc_create("ip_vs", 0, net->proc_net, &ip_vs_info_fops);