[IPV4]: Do not disable preemption in trie_leaf_remove().

Hello, Just discussed this Patrick...

We have two users of trie_leaf_remove, fn_trie_flush and fn_trie_delete
both are holding RTNL. So there shouldn't be need for this preempt stuff.
This is assumed to a leftover from an older RCU-take.

> Mhh .. I think I just remembered something - me incorrectly suggesting
> to add it there while we were talking about this at OLS :) IIRC the
> idea was to make sure tnode_free (which at that time didn't use
> call_rcu) wouldn't free memory while still in use in a rcu read-side
> critical section. It should have been synchronize_rcu of course,
> but with tnode_free using call_rcu it seems to be completely
> unnecessary. So I guess we can simply remove it.

Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 2 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 72b3036bbc09..ada9b3db507d 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1527,7 +1527,6 @@ static int trie_leaf_remove(struct trie *t, t_key key)
         t->revision++;
         t->size--;
 
-        preempt_disable();
         tp = NODE_PARENT(n);
         tnode_free((struct tnode *) n);
 
@@ -1537,7 +1536,6 @@ static int trie_leaf_remove(struct trie *t, t_key key)
                 rcu_assign_pointer(t->trie, trie_rebalance(t, tp));
         } else
                 rcu_assign_pointer(t->trie, NULL);
-        preempt_enable();
 
         return 1;
 }