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Diffstat (limited to 'net/ipv4/route.c')
-rw-r--r--net/ipv4/route.c50
1 files changed, 38 insertions, 12 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b2ba5581d2ae..d9b40248b97f 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -146,7 +146,6 @@ static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
static void ipv4_link_failure(struct sk_buff *skb);
static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
static int rt_garbage_collect(struct dst_ops *ops);
-static void rt_emergency_hash_rebuild(struct net *net);
static struct dst_ops ipv4_dst_ops = {
@@ -780,11 +779,30 @@ static void rt_do_flush(int process_context)
#define FRACT_BITS 3
#define ONE (1UL << FRACT_BITS)
+/*
+ * Given a hash chain and an item in this hash chain,
+ * find if a previous entry has the same hash_inputs
+ * (but differs on tos, mark or oif)
+ * Returns 0 if an alias is found.
+ * Returns ONE if rth has no alias before itself.
+ */
+static int has_noalias(const struct rtable *head, const struct rtable *rth)
+{
+ const struct rtable *aux = head;
+
+ while (aux != rth) {
+ if (compare_hash_inputs(&aux->fl, &rth->fl))
+ return 0;
+ aux = aux->u.dst.rt_next;
+ }
+ return ONE;
+}
+
static void rt_check_expire(void)
{
static unsigned int rover;
unsigned int i = rover, goal;
- struct rtable *rth, *aux, **rthp;
+ struct rtable *rth, **rthp;
unsigned long samples = 0;
unsigned long sum = 0, sum2 = 0;
unsigned long delta;
@@ -835,15 +853,7 @@ nofree:
* attributes don't unfairly skew
* the length computation
*/
- for (aux = rt_hash_table[i].chain;;) {
- if (aux == rth) {
- length += ONE;
- break;
- }
- if (compare_hash_inputs(&aux->fl, &rth->fl))
- break;
- aux = aux->u.dst.rt_next;
- }
+ length += has_noalias(rt_hash_table[i].chain, rth);
continue;
}
} else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout))
@@ -1073,6 +1083,21 @@ work_done:
out: return 0;
}
+/*
+ * Returns number of entries in a hash chain that have different hash_inputs
+ */
+static int slow_chain_length(const struct rtable *head)
+{
+ int length = 0;
+ const struct rtable *rth = head;
+
+ while (rth) {
+ length += has_noalias(head, rth);
+ rth = rth->u.dst.rt_next;
+ }
+ return length >> FRACT_BITS;
+}
+
static int rt_intern_hash(unsigned hash, struct rtable *rt,
struct rtable **rp, struct sk_buff *skb)
{
@@ -1185,7 +1210,8 @@ restart:
rt_free(cand);
}
} else {
- if (chain_length > rt_chain_length_max) {
+ if (chain_length > rt_chain_length_max &&
+ slow_chain_length(rt_hash_table[hash].chain) > rt_chain_length_max) {
struct net *net = dev_net(rt->u.dst.dev);
int num = ++net->ipv4.current_rt_cache_rebuild_count;
if (!rt_caching(dev_net(rt->u.dst.dev))) {