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fib_trie: Various clean-ups for handling slen

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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 <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Duyck 2015-01-22 15:51:45 -08:00 committed by David S. Miller
parent 02525368f4
commit 64c6272351
1 changed files with 29 additions and 20 deletions
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49
net/ipv4/fib_trie.c
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@ -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;