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	also refresh generic patches for 3.14, 3.18, 3.19 and 4.0 targets might need a minor refresh as well, however, it looks like everything still applies cleanly with occasional small offsets. Signed-off-by: Daniel Golle <daniel@makrotopia.org> SVN-Revision: 44876
		
			
				
	
	
		
			238 lines
		
	
	
		
			5.5 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			238 lines
		
	
	
		
			5.5 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From: Alexander Duyck <alexander.h.duyck@redhat.com>
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| Date: Wed, 31 Dec 2014 10:56:49 -0800
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| Subject: [PATCH] fib_trie: Push tnode flushing down to inflate/halve
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| 
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| This change pushes the tnode freeing down into the inflate and halve
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| functions.  It makes more sense here as we have a better grasp of what is
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| going on and when a given cluster of nodes is ready to be freed.
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| 
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| I believe this may address a bug in the freeing logic as well.  For some
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| reason if the freelist got to a certain size we would call
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| synchronize_rcu().  I'm assuming that what they meant to do is call
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| synchronize_rcu() after they had handed off that much memory via
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| call_rcu().  As such that is what I have updated the behavior to be.
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| 
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| Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
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| Signed-off-by: David S. Miller <davem@davemloft.net>
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| ---
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| 
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| --- a/net/ipv4/fib_trie.c
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| +++ b/net/ipv4/fib_trie.c
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| @@ -147,8 +147,6 @@ struct trie {
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|  };
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|  
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|  static void resize(struct trie *t, struct tnode *tn);
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| -/* tnodes to free after resize(); protected by RTNL */
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| -static struct callback_head *tnode_free_head;
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|  static size_t tnode_free_size;
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|  
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|  /*
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| @@ -307,32 +305,6 @@ static struct tnode *tnode_alloc(size_t
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|  		return vzalloc(size);
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|  }
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|  
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| -static void tnode_free_safe(struct tnode *tn)
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| -{
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| -	BUG_ON(IS_LEAF(tn));
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| -	tn->rcu.next = tnode_free_head;
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| -	tnode_free_head = &tn->rcu;
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| -}
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| -
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| -static void tnode_free_flush(void)
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| -{
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| -	struct callback_head *head;
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| -
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| -	while ((head = tnode_free_head)) {
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| -		struct tnode *tn = container_of(head, struct tnode, rcu);
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| -
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| -		tnode_free_head = head->next;
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| -		tnode_free_size += offsetof(struct tnode, child[1 << tn->bits]);
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| -
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| -		node_free(tn);
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| -	}
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| -
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| -	if (tnode_free_size >= PAGE_SIZE * sync_pages) {
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| -		tnode_free_size = 0;
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| -		synchronize_rcu();
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| -	}
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| -}
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| -
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|  static struct tnode *leaf_new(t_key key)
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|  {
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|  	struct tnode *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
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| @@ -433,17 +405,33 @@ static void put_child_root(struct tnode
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|  		rcu_assign_pointer(t->trie, n);
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|  }
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|  
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| -static void tnode_clean_free(struct tnode *tn)
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| +static inline void tnode_free_init(struct tnode *tn)
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|  {
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| -	struct tnode *tofree;
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| -	unsigned long i;
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| +	tn->rcu.next = NULL;
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| +}
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| +
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| +static inline void tnode_free_append(struct tnode *tn, struct tnode *n)
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| +{
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| +	n->rcu.next = tn->rcu.next;
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| +	tn->rcu.next = &n->rcu;
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| +}
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|  
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| -	for (i = 0; i < tnode_child_length(tn); i++) {
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| -		tofree = tnode_get_child(tn, i);
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| -		if (tofree)
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| -			node_free(tofree);
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| +static void tnode_free(struct tnode *tn)
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| +{
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| +	struct callback_head *head = &tn->rcu;
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| +
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| +	while (head) {
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| +		head = head->next;
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| +		tnode_free_size += offsetof(struct tnode, child[1 << tn->bits]);
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| +		node_free(tn);
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| +
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| +		tn = container_of(head, struct tnode, rcu);
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| +	}
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| +
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| +	if (tnode_free_size >= PAGE_SIZE * sync_pages) {
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| +		tnode_free_size = 0;
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| +		synchronize_rcu();
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|  	}
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| -	node_free(tn);
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|  }
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|  
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|  static int inflate(struct trie *t, struct tnode *oldtnode)
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| @@ -476,20 +464,23 @@ static int inflate(struct trie *t, struc
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|  					 inode->bits - 1);
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|  			if (!left)
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|  				goto nomem;
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| +			tnode_free_append(tn, left);
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|  
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|  			right = tnode_new(inode->key | m, inode->pos,
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|  					  inode->bits - 1);
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|  
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| -			if (!right) {
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| -				node_free(left);
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| +			if (!right)
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|  				goto nomem;
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| -			}
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| +			tnode_free_append(tn, right);
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|  
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|  			put_child(tn, 2*i, left);
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|  			put_child(tn, 2*i+1, right);
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|  		}
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|  	}
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|  
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| +	/* prepare oldtnode to be freed */
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| +	tnode_free_init(oldtnode);
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| +
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|  	for (i = 0; i < olen; i++) {
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|  		struct tnode *inode = tnode_get_child(oldtnode, i);
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|  		struct tnode *left, *right;
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| @@ -505,12 +496,13 @@ static int inflate(struct trie *t, struc
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|  			continue;
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|  		}
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|  
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| +		/* drop the node in the old tnode free list */
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| +		tnode_free_append(oldtnode, inode);
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| +
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|  		/* An internal node with two children */
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|  		if (inode->bits == 1) {
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|  			put_child(tn, 2*i, rtnl_dereference(inode->child[0]));
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|  			put_child(tn, 2*i+1, rtnl_dereference(inode->child[1]));
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| -
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| -			tnode_free_safe(inode);
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|  			continue;
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|  		}
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|  
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| @@ -556,17 +548,19 @@ static int inflate(struct trie *t, struc
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|  		put_child(tn, 2 * i, left);
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|  		put_child(tn, 2 * i + 1, right);
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|  
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| -		tnode_free_safe(inode);
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| -
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| +		/* resize child nodes */
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|  		resize(t, left);
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|  		resize(t, right);
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|  	}
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|  
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|  	put_child_root(tp, t, tn->key, tn);
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| -	tnode_free_safe(oldtnode);
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| +
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| +	/* we completed without error, prepare to free old node */
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| +	tnode_free(oldtnode);
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|  	return 0;
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|  nomem:
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| -	tnode_clean_free(tn);
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| +	/* all pointers should be clean so we are done */
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| +	tnode_free(tn);
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|  	return -ENOMEM;
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|  }
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|  
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| @@ -599,17 +593,20 @@ static int halve(struct trie *t, struct
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|  			struct tnode *newn;
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|  
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|  			newn = tnode_new(left->key, oldtnode->pos, 1);
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| -
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|  			if (!newn) {
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| -				tnode_clean_free(tn);
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| +				tnode_free(tn);
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|  				return -ENOMEM;
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|  			}
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| +			tnode_free_append(tn, newn);
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|  
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|  			put_child(tn, i/2, newn);
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|  		}
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|  
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|  	}
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|  
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| +	/* prepare oldtnode to be freed */
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| +	tnode_free_init(oldtnode);
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| +
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|  	for (i = 0; i < olen; i += 2) {
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|  		struct tnode *newBinNode;
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|  
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| @@ -636,11 +633,14 @@ static int halve(struct trie *t, struct
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|  
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|  		put_child(tn, i / 2, newBinNode);
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|  
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| +		/* resize child node */
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|  		resize(t, newBinNode);
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|  	}
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|  
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|  	put_child_root(tp, t, tn->key, tn);
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| -	tnode_free_safe(oldtnode);
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| +
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| +	/* all pointers should be clean so we are done */
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| +	tnode_free(oldtnode);
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|  
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|  	return 0;
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|  }
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| @@ -798,7 +798,8 @@ no_children:
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|  		node_set_parent(n, tp);
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|  
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|  		/* drop dead node */
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| -		tnode_free_safe(tn);
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| +		tnode_free_init(tn);
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| +		tnode_free(tn);
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|  	}
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|  }
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|  
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| @@ -884,16 +885,12 @@ static void trie_rebalance(struct trie *
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|  
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|  	while ((tp = node_parent(tn)) != NULL) {
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|  		resize(t, tn);
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| -
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| -		tnode_free_flush();
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|  		tn = tp;
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|  	}
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|  
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|  	/* Handle last (top) tnode */
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|  	if (IS_TNODE(tn))
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|  		resize(t, tn);
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| -
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| -	tnode_free_flush();
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|  }
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|  
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|  /* only used from updater-side */
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