From abb81c4f3cb9b8d421f1e5474811ef1d461d341c Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 9 Sep 2008 19:58:29 -0700 Subject: ipsec: Use RCU-like construct for saved state within a walk Now that we save states within a walk we need synchronisation so that the list the saved state is on doesn't disappear from under us. As it stands this is done by keeping the state on the list which is bad because it gets in the way of the management of the state life-cycle. An alternative is to make our own pseudo-RCU system where we use counters to indicate which state can't be freed immediately as it may be referenced by an ongoing walk when that resumes. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/net/xfrm.h | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'include') diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 2933d7474a7..4bb94992b5f 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -120,9 +120,11 @@ extern struct mutex xfrm_cfg_mutex; /* Full description of state of transformer. */ struct xfrm_state { - /* Note: bydst is re-used during gc */ struct list_head all; - struct hlist_node bydst; + union { + struct list_head gclist; + struct hlist_node bydst; + }; struct hlist_node bysrc; struct hlist_node byspi; @@ -1286,16 +1288,9 @@ static inline void xfrm_state_walk_init(struct xfrm_state_walk *walk, u8 proto) walk->count = 0; } -static inline void xfrm_state_walk_done(struct xfrm_state_walk *walk) -{ - if (walk->state != NULL) { - xfrm_state_put(walk->state); - walk->state = NULL; - } -} - extern int xfrm_state_walk(struct xfrm_state_walk *walk, int (*func)(struct xfrm_state *, int, void*), void *); +extern void xfrm_state_walk_done(struct xfrm_state_walk *walk); extern struct xfrm_state *xfrm_state_alloc(void); extern struct xfrm_state *xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr, struct flowi *fl, struct xfrm_tmpl *tmpl, -- cgit v1.2.3