From 64c6272351a0eca55574f487b103770163d1dbce Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Thu, 22 Jan 2015 15:51:45 -0800 Subject: [PATCH] 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: Alexander Duyck Signed-off-by: David S. Miller --- net/ipv4/fib_trie.c | 49 +++++++++++++++++++++++++++------------------ 1 file changed, 29 insertions(+), 20 deletions(-) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index 7f342265968e..3daf0224ff2e 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -917,27 +917,20 @@ 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); - - l->slen = KEYLENGTH - li->plen; - leaf_pull_suffix(l); - } + /* 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)) - trie_leaf_remove(t, ll); + 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)) - trie_leaf_remove(t, ll); + 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; -- 2.20.1