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authorDavid S. Miller <davem@davemloft.net>2012-07-19 23:31:33 +0400
committerDavid S. Miller <davem@davemloft.net>2012-07-21 00:31:21 +0400
commitf5b0a8743601a4477419171f5046bd07d1c080a0 (patch)
tree92e17ec293c3d0e35a0deda5d3bbf43710fb96ff /net/xfrm
parentf8126f1d5136be1ca1a3536d43ad7a710b5620f8 (diff)
downloadlinux-f5b0a8743601a4477419171f5046bd07d1c080a0.tar.xz
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 <davem@davemloft.net>
Diffstat (limited to 'net/xfrm')
-rw-r--r--net/xfrm/xfrm_policy.c23
1 files changed, 12 insertions, 11 deletions
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;