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Commit afcf1242 authored by Timo Teras's avatar Timo Teras Committed by David S. Miller
Browse files

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: default avatarTimo Teras <timo.teras@iki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3eacdf58

net/ipv4/ip_gre.c

+40 −29
Original line number Diff line number Diff line
@@ -172,11 +172,11 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 
	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 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 
		    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 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 
		    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 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 
		    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 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 
		    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);