xfrm: add state hashtable keyed by seq

When creating new states with seq set in xfrm_usersa_info, we walk
through all the states already installed in that netns to find a
matching ACQUIRE state (__xfrm_find_acq_byseq, called from
xfrm_state_add). This causes severe slowdowns on systems with a large
number of states.

This patch introduces a hashtable using x->km.seq as key, so that the
corresponding state can be found in a reasonable time.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index c58a6d4eb610..6e11db6fa0ab 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -154,6 +154,7 @@ struct xfrm_state {
 	};
 	struct hlist_node	bysrc;
 	struct hlist_node	byspi;
+	struct hlist_node	byseq;
 
 	refcount_t		refcnt;
 	spinlock_t		lock;