From f5b0a8743601a4477419171f5046bd07d1c080a0 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Thu, 19 Jul 2012 12:31:33 -0700 Subject: net: Document dst->obsolete better. Add a big comment explaining how the field works, and use defines instead of magic constants for the values assigned to it. Suggested by Joe Perches. Signed-off-by: David S. Miller --- net/xfrm/xfrm_policy.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) (limited to 'net/xfrm') diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 65bd1ca51517..c5a5165a5927 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1350,7 +1350,7 @@ static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family) default: BUG(); } - xdst = dst_alloc(dst_ops, NULL, 0, 0, 0); + xdst = dst_alloc(dst_ops, NULL, 0, DST_OBSOLETE_NONE, 0); if (likely(xdst)) { struct dst_entry *dst = &xdst->u.dst; @@ -1477,7 +1477,7 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy, dst1->xfrm = xfrm[i]; xdst->xfrm_genid = xfrm[i]->genid; - dst1->obsolete = -1; + dst1->obsolete = DST_OBSOLETE_FORCE_CHK; dst1->flags |= DST_HOST; dst1->lastuse = now; @@ -2219,12 +2219,13 @@ EXPORT_SYMBOL(__xfrm_route_forward); static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie) { /* Code (such as __xfrm4_bundle_create()) sets dst->obsolete - * to "-1" to force all XFRM destinations to get validated by - * dst_ops->check on every use. We do this because when a - * normal route referenced by an XFRM dst is obsoleted we do - * not go looking around for all parent referencing XFRM dsts - * so that we can invalidate them. It is just too much work. - * Instead we make the checks here on every use. For example: + * to DST_OBSOLETE_FORCE_CHK to force all XFRM destinations to + * get validated by dst_ops->check on every use. We do this + * because when a normal route referenced by an XFRM dst is + * obsoleted we do not go looking around for all parent + * referencing XFRM dsts so that we can invalidate them. It + * is just too much work. Instead we make the checks here on + * every use. For example: * * XFRM dst A --> IPv4 dst X * @@ -2234,9 +2235,9 @@ static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie) * stale_bundle() check. * * When a policy's bundle is pruned, we dst_free() the XFRM - * dst which causes it's ->obsolete field to be set to a - * positive non-zero integer. If an XFRM dst has been pruned - * like this, we want to force a new route lookup. + * dst which causes it's ->obsolete field to be set to + * DST_OBSOLETE_DEAD. If an XFRM dst has been pruned like + * this, we want to force a new route lookup. */ if (dst->obsolete < 0 && !stale_bundle(dst)) return dst; -- cgit v1.2.3