[DECNET] ROUTE: fix rcu_dereference() uses in /proc/net/decnet_cache

[Eric Dumazet]

Hi David

Here is DECNET part, shadowing commit 0bcceadceb0907094ba4e40bf9a7cd9b080f13fb 
([IPV4] ROUTE: fix rcu_dereference() uses in /proc/net/rt_cache )

Thank you


[DECNET] ROUTE: fix rcu_dereference() uses in /proc/net/decnet_cache

In dn_rt_cache_get_next(), no need to guard seq->private by a rcu_dereference()
since seq is private to the thread running this function. Reading seq.private
once (as guaranted bu rcu_dereference()) or several time if compiler really is 
dumb enough wont change the result.
 
But we miss real spots where rcu_dereference() are needed, both in 
dn_rt_cache_get_first() and dn_rt_cache_get_next()

Signed-off-by: Eric Dumazet <[EMAIL PROTECTED]>

diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 66663e5..0e10ff2 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1665,12 +1665,12 @@ static struct dn_route *dn_rt_cache_get_first(struct 
seq_file *seq)
                        break;
                rcu_read_unlock_bh();
        }
-       return rt;
+       return rcu_dereference(rt);
 }
 
 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct 
dn_route *rt)
 {
-       struct dn_rt_cache_iter_state *s = rcu_dereference(seq->private);
+       struct dn_rt_cache_iter_state *s = seq->private;
 
        rt = rt->u.dst.dn_next;
        while(!rt) {
@@ -1680,7 +1680,7 @@ 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 rt;
+       return rcu_dereference(rt);
 }
 
 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
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