gre: optimize hash lookup
Instead of keeping candidate tunnel device from all categories,
keep only one candidate with best score. This optimizes stack
usage and speeds up exit code.
Signed-off-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 4a43739..07a188a 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -172,11 +172,11 @@
int link = dev->ifindex;
unsigned h0 = HASH(remote);
unsigned h1 = HASH(key);
- struct ip_tunnel *t, *sel[4] = { NULL, NULL, NULL, NULL };
+ struct ip_tunnel *t, *cand = NULL;
struct ipgre_net *ign = net_generic(net, ipgre_net_id);
int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
ARPHRD_ETHER : ARPHRD_IPGRE;
- int idx;
+ int score, cand_score = 4;
for (t = ign->tunnels_r_l[h0^h1]; t; t = t->next) {
if (local != t->parms.iph.saddr ||
@@ -189,15 +189,18 @@
t->dev->type != dev_type)
continue;
- idx = 0;
+ score = 0;
if (t->parms.link != link)
- idx |= 1;
+ score |= 1;
if (t->dev->type != dev_type)
- idx |= 2;
- if (idx == 0)
+ score |= 2;
+ if (score == 0)
return t;
- if (sel[idx] == NULL)
- sel[idx] = t;
+
+ if (score < cand_score) {
+ cand = t;
+ cand_score = score;
+ }
}
for (t = ign->tunnels_r[h0^h1]; t; t = t->next) {
@@ -210,15 +213,18 @@
t->dev->type != dev_type)
continue;
- idx = 0;
+ score = 0;
if (t->parms.link != link)
- idx |= 1;
+ score |= 1;
if (t->dev->type != dev_type)
- idx |= 2;
- if (idx == 0)
+ score |= 2;
+ if (score == 0)
return t;
- if (sel[idx] == NULL)
- sel[idx] = t;
+
+ if (score < cand_score) {
+ cand = t;
+ cand_score = score;
+ }
}
for (t = ign->tunnels_l[h1]; t; t = t->next) {
@@ -233,15 +239,18 @@
t->dev->type != dev_type)
continue;
- idx = 0;
+ score = 0;
if (t->parms.link != link)
- idx |= 1;
+ score |= 1;
if (t->dev->type != dev_type)
- idx |= 2;
- if (idx == 0)
+ score |= 2;
+ if (score == 0)
return t;
- if (sel[idx] == NULL)
- sel[idx] = t;
+
+ if (score < cand_score) {
+ cand = t;
+ cand_score = score;
+ }
}
for (t = ign->tunnels_wc[h1]; t; t = t->next) {
@@ -253,20 +262,22 @@
t->dev->type != dev_type)
continue;
- idx = 0;
+ score = 0;
if (t->parms.link != link)
- idx |= 1;
+ score |= 1;
if (t->dev->type != dev_type)
- idx |= 2;
- if (idx == 0)
+ score |= 2;
+ if (score == 0)
return t;
- if (sel[idx] == NULL)
- sel[idx] = t;
+
+ if (score < cand_score) {
+ cand = t;
+ cand_score = score;
+ }
}
- for (idx = 1; idx < ARRAY_SIZE(sel); idx++)
- if (sel[idx] != NULL)
- return sel[idx];
+ if (cand != NULL)
+ return cand;
if (ign->fb_tunnel_dev->flags & IFF_UP)
return netdev_priv(ign->fb_tunnel_dev);