Fix GFP_KERNEL with preemption disabled in fib_trie

[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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 1e589b91605efa36518f0abe338a7adc674bd38e..a742ea3ff1d0247423efb292dd615f4812ac52be 100644 (file)
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1528,7 +1528,6 @@ 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);
 
@@ -1538,7 +1537,6 @@ 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;
 }