aboutsummaryrefslogtreecommitdiffstats
path: root/net/xfrm/xfrm_state.c
diff options
context:
space:
mode:
authorHerbert Xu <herbert@gondor.apana.org.au>2008-09-09 19:58:29 -0700
committerDavid S. Miller <davem@davemloft.net>2008-09-09 19:58:29 -0700
commitabb81c4f3cb9b8d421f1e5474811ef1d461d341c (patch)
tree71a08df3a53eb9e19a62c673d77084e4d81f708b /net/xfrm/xfrm_state.c
parentdacc62dbf56e872ad96edde0393b9deb56d80cd5 (diff)
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 <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/xfrm/xfrm_state.c')
-rw-r--r--net/xfrm/xfrm_state.c52
1 files changed, 39 insertions, 13 deletions
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 0a8f09c3144c..aaafcee02fc5 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -59,6 +59,11 @@ static unsigned int xfrm_state_hashmax __read_mostly = 1 * 1024 * 1024;
static unsigned int xfrm_state_num;
static unsigned int xfrm_state_genid;
+/* Counter indicating ongoing walk, protected by xfrm_state_lock. */
+static unsigned long xfrm_state_walk_ongoing;
+/* Counter indicating walk completion, protected by xfrm_cfg_mutex. */
+static unsigned long xfrm_state_walk_completed;
+
static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family);
static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo);
@@ -191,7 +196,8 @@ static DEFINE_RWLOCK(xfrm_state_afinfo_lock);
static struct xfrm_state_afinfo *xfrm_state_afinfo[NPROTO];
static struct work_struct xfrm_state_gc_work;
-static HLIST_HEAD(xfrm_state_gc_list);
+static LIST_HEAD(xfrm_state_gc_leftovers);
+static LIST_HEAD(xfrm_state_gc_list);
static DEFINE_SPINLOCK(xfrm_state_gc_lock);
int __xfrm_state_delete(struct xfrm_state *x);
@@ -403,17 +409,22 @@ static void xfrm_state_gc_destroy(struct xfrm_state *x)
static void xfrm_state_gc_task(struct work_struct *data)
{
- struct xfrm_state *x;
- struct hlist_node *entry, *tmp;
- struct hlist_head gc_list;
+ struct xfrm_state *x, *tmp;
+ unsigned long completed;
+ mutex_lock(&xfrm_cfg_mutex);
spin_lock_bh(&xfrm_state_gc_lock);
- gc_list.first = xfrm_state_gc_list.first;
- INIT_HLIST_HEAD(&xfrm_state_gc_list);
+ list_splice_tail_init(&xfrm_state_gc_list, &xfrm_state_gc_leftovers);
spin_unlock_bh(&xfrm_state_gc_lock);
- hlist_for_each_entry_safe(x, entry, tmp, &gc_list, bydst)
+ completed = xfrm_state_walk_completed;
+ mutex_unlock(&xfrm_cfg_mutex);
+
+ list_for_each_entry_safe(x, tmp, &xfrm_state_gc_leftovers, gclist) {
+ if ((long)(x->lastused - completed) > 0)
+ break;
xfrm_state_gc_destroy(x);
+ }
wake_up(&km_waitq);
}
@@ -540,12 +551,8 @@ void __xfrm_state_destroy(struct xfrm_state *x)
{
WARN_ON(x->km.state != XFRM_STATE_DEAD);
- spin_lock_bh(&xfrm_state_lock);
- list_del(&x->all);
- spin_unlock_bh(&xfrm_state_lock);
-
spin_lock_bh(&xfrm_state_gc_lock);
- hlist_add_head(&x->bydst, &xfrm_state_gc_list);
+ list_add_tail(&x->gclist, &xfrm_state_gc_list);
spin_unlock_bh(&xfrm_state_gc_lock);
schedule_work(&xfrm_state_gc_work);
}
@@ -558,6 +565,8 @@ int __xfrm_state_delete(struct xfrm_state *x)
if (x->km.state != XFRM_STATE_DEAD) {
x->km.state = XFRM_STATE_DEAD;
spin_lock(&xfrm_state_lock);
+ x->lastused = xfrm_state_walk_ongoing;
+ list_del_rcu(&x->all);
hlist_del(&x->bydst);
hlist_del(&x->bysrc);
if (x->id.spi)
@@ -1574,6 +1583,7 @@ int xfrm_state_walk(struct xfrm_state_walk *walk,
if (err) {
xfrm_state_hold(last);
walk->state = last;
+ xfrm_state_walk_ongoing++;
goto out;
}
}
@@ -1588,12 +1598,28 @@ int xfrm_state_walk(struct xfrm_state_walk *walk,
err = func(last, 0, data);
out:
spin_unlock_bh(&xfrm_state_lock);
- if (old != NULL)
+ if (old != NULL) {
xfrm_state_put(old);
+ xfrm_state_walk_completed++;
+ if (!list_empty(&xfrm_state_gc_leftovers))
+ schedule_work(&xfrm_state_gc_work);
+ }
return err;
}
EXPORT_SYMBOL(xfrm_state_walk);
+void xfrm_state_walk_done(struct xfrm_state_walk *walk)
+{
+ if (walk->state != NULL) {
+ xfrm_state_put(walk->state);
+ walk->state = NULL;
+ xfrm_state_walk_completed++;
+ if (!list_empty(&xfrm_state_gc_leftovers))
+ schedule_work(&xfrm_state_gc_work);
+ }
+}
+EXPORT_SYMBOL(xfrm_state_walk_done);
+
void xfrm_replay_notify(struct xfrm_state *x, int event)
{

Privacy Policy