Commit 64c62723 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

fib_trie: Various clean-ups for handling slen 



While doing further work on the fib_trie I noted a few items.

First I was using calls that were far more complicated than they needed to
be for determining when to push/pull the suffix length.  I have updated the
code to reflect the simplier logic.

The second issue is that I realised we weren't necessarily handling the
case of a leaf_info struct surviving a flush.  I have updated the logic so
that now we will call pull_suffix in the event of having a leaf info value
left in the leaf after flushing it.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 02525368

net/ipv4/fib_trie.c

+29 −20
Original line number Diff line number Diff line
@@ -917,28 +917,21 @@ static void leaf_push_suffix(struct tnode *l) 


static void remove_leaf_info(struct tnode *l, struct leaf_info *old)

{

	struct hlist_node *prev;



	/* record the location of the pointer to this object */

	prev = rtnl_dereference(hlist_pprev_rcu(&old->hlist));

	/* record the location of the previous list_info entry */

	struct hlist_node **pprev = old->hlist.pprev;

	struct leaf_info *li = hlist_entry(pprev, typeof(*li), hlist.next);



	/* remove the leaf info from the list */

	hlist_del_rcu(&old->hlist);



	/* if we emptied the list this leaf will be freed and we can sort

	 * out parent suffix lengths as a part of trie_rebalance

	 */

	if (hlist_empty(&l->list))

	/* only access li if it is pointing at the last valid hlist_node */

	if (hlist_empty(&l->list) || (*pprev))

		return;



	/* if we removed the tail then we need to update slen */

	if (!rcu_access_pointer(hlist_next_rcu(prev))) {

		struct leaf_info *li = hlist_entry(prev, typeof(*li), hlist);



	/* update the trie with the latest suffix length */

	l->slen = KEYLENGTH - li->plen;

	leaf_pull_suffix(l);

}

}



static void insert_leaf_info(struct tnode *l, struct leaf_info *new)

{
@@ -961,7 +954,7 @@ static void insert_leaf_info(struct tnode *l, struct leaf_info *new) 
	}



	/* if we added to the tail node then we need to update slen */

	if (!rcu_access_pointer(hlist_next_rcu(&new->hlist))) {

	if (l->slen < (KEYLENGTH - new->plen)) {

		l->slen = KEYLENGTH - new->plen;

		leaf_push_suffix(l);

	}
@@ -1613,6 +1606,7 @@ static int trie_flush_leaf(struct tnode *l) 
	struct hlist_head *lih = &l->list;

	struct hlist_node *tmp;

	struct leaf_info *li = NULL;

	unsigned char plen = KEYLENGTH;



	hlist_for_each_entry_safe(li, tmp, lih, hlist) {

		found += trie_flush_list(&li->falh);
@@ -1620,8 +1614,14 @@ static int trie_flush_leaf(struct tnode *l) 
		if (list_empty(&li->falh)) {

			hlist_del_rcu(&li->hlist);

			free_leaf_info(li);

			continue;

		}



		plen = li->plen;

	}



	l->slen = KEYLENGTH - plen;



	return found;

}
@@ -1700,13 +1700,22 @@ int fib_table_flush(struct fib_table *tb) 
	for (l = trie_firstleaf(t); l; l = trie_nextleaf(l)) {

		found += trie_flush_leaf(l);



		if (ll && hlist_empty(&ll->list))

		if (ll) {

			if (hlist_empty(&ll->list))

				trie_leaf_remove(t, ll);

			else

				leaf_pull_suffix(ll);

		}



		ll = l;

	}



	if (ll && hlist_empty(&ll->list))

	if (ll) {

		if (hlist_empty(&ll->list))

			trie_leaf_remove(t, ll);

		else

			leaf_pull_suffix(ll);

	}



	pr_debug("trie_flush found=%d\n", found);

	return found;

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