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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 <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) static void remove_leaf_info(struct tnode *l, struct leaf_info *old)
{ {
struct hlist_node *prev; /* record the location of the previous list_info entry */
struct hlist_node **pprev = old->hlist.pprev;
/* record the location of the pointer to this object */ struct leaf_info *li = hlist_entry(pprev, typeof(*li), hlist.next);
prev = rtnl_dereference(hlist_pprev_rcu(&old->hlist));
/* remove the leaf info from the list */ /* remove the leaf info from the list */
hlist_del_rcu(&old->hlist); hlist_del_rcu(&old->hlist);
/* if we emptied the list this leaf will be freed and we can sort /* only access li if it is pointing at the last valid hlist_node */
* out parent suffix lengths as a part of trie_rebalance if (hlist_empty(&l->list) || (*pprev))
*/
if (hlist_empty(&l->list))
return; return;
/* if we removed the tail then we need to update slen */ /* update the trie with the latest suffix length */
if (!rcu_access_pointer(hlist_next_rcu(prev))) { l->slen = KEYLENGTH - li->plen;
struct leaf_info *li = hlist_entry(prev, typeof(*li), hlist); leaf_pull_suffix(l);
l->slen = KEYLENGTH - li->plen;
leaf_pull_suffix(l);
}
} }
static void insert_leaf_info(struct tnode *l, struct leaf_info *new) 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 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; l->slen = KEYLENGTH - new->plen;
leaf_push_suffix(l); leaf_push_suffix(l);
} }
@ -1613,6 +1606,7 @@ static int trie_flush_leaf(struct tnode *l)
struct hlist_head *lih = &l->list; struct hlist_head *lih = &l->list;
struct hlist_node *tmp; struct hlist_node *tmp;
struct leaf_info *li = NULL; struct leaf_info *li = NULL;
unsigned char plen = KEYLENGTH;
hlist_for_each_entry_safe(li, tmp, lih, hlist) { hlist_for_each_entry_safe(li, tmp, lih, hlist) {
found += trie_flush_list(&li->falh); found += trie_flush_list(&li->falh);
@ -1620,8 +1614,14 @@ static int trie_flush_leaf(struct tnode *l)
if (list_empty(&li->falh)) { if (list_empty(&li->falh)) {
hlist_del_rcu(&li->hlist); hlist_del_rcu(&li->hlist);
free_leaf_info(li); free_leaf_info(li);
continue;
} }
plen = li->plen;
} }
l->slen = KEYLENGTH - plen;
return found; return found;
} }
@ -1700,13 +1700,22 @@ int fib_table_flush(struct fib_table *tb)
for (l = trie_firstleaf(t); l; l = trie_nextleaf(l)) { for (l = trie_firstleaf(t); l; l = trie_nextleaf(l)) {
found += trie_flush_leaf(l); found += trie_flush_leaf(l);
if (ll && hlist_empty(&ll->list)) if (ll) {
trie_leaf_remove(t, ll); if (hlist_empty(&ll->list))
trie_leaf_remove(t, ll);
else
leaf_pull_suffix(ll);
}
ll = l; ll = l;
} }
if (ll && hlist_empty(&ll->list)) if (ll) {
trie_leaf_remove(t, ll); if (hlist_empty(&ll->list))
trie_leaf_remove(t, ll);
else
leaf_pull_suffix(ll);
}
pr_debug("trie_flush found=%d\n", found); pr_debug("trie_flush found=%d\n", found);
return found; return found;