net: Add checking to rcu_dereference() primitives

Update rcu_dereference() primitives to use new lockdep-based
checking. The rcu_dereference() in __in6_dev_get() may be
protected either by rcu_read_lock() or RTNL, per Eric Dumazet.
The rcu_dereference() in __sk_free() is protected by the fact
that it is never reached if an update could change it.  Check
for this by using rcu_dereference_check() to verify that the
struct sock's ->sk_wmem_alloc counter is zero.

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-5-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 7 deletions

diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index a03284061a31..a7bf03ca0a36 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1155,8 +1155,8 @@ static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *fl
 
         if (!(flags & MSG_TRYHARD)) {
                 rcu_read_lock_bh();
-                for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
-                        rt = rcu_dereference(rt->u.dst.dn_next)) {
+                for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
+                        rt = rcu_dereference_bh(rt->u.dst.dn_next)) {
                         if ((flp->fld_dst == rt->fl.fld_dst) &&
                             (flp->fld_src == rt->fl.fld_src) &&
                             (flp->mark == rt->fl.mark) &&
@@ -1618,9 +1618,9 @@ int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
                 if (h > s_h)
                         s_idx = 0;
                 rcu_read_lock_bh();
-                for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
+                for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
                         rt;
-                        rt = rcu_dereference(rt->u.dst.dn_next), idx++) {
+                        rt = rcu_dereference_bh(rt->u.dst.dn_next), idx++) {
                         if (idx < s_idx)
                                 continue;
                         skb_dst_set(skb, dst_clone(&rt->u.dst));
@@ -1654,12 +1654,12 @@ static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
 
         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
                 rcu_read_lock_bh();
-                rt = dn_rt_hash_table[s->bucket].chain;
+                rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
                 if (rt)
                         break;
                 rcu_read_unlock_bh();
         }
-        return rcu_dereference(rt);
+        return rt;
 }
 
 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
@@ -1674,7 +1674,7 @@ static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_rou
                 rcu_read_lock_bh();
                 rt = dn_rt_hash_table[s->bucket].chain;
         }
-        return rcu_dereference(rt);
+        return rcu_dereference_bh(rt);
 }
 
 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)