xfrm: cache bundles instead of policies for outgoing flows

__xfrm_lookup() is called for each packet transmitted out of
system. The xfrm_find_bundle() does a linear search which can
kill system performance depending on how many bundles are
required per policy.

This modifies __xfrm_lookup() to store bundles directly in
the flow cache. If we did not get a hit, we just create a new
bundle instead of doing slow search. This means that we can now
get multiple xfrm_dst's for same flow (on per-cpu basis).

Signed-off-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 376 insertions, 335 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 7722baeb140d..06ccc71c871f 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -37,6 +37,8 @@
 DEFINE_MUTEX(xfrm_cfg_mutex);
 EXPORT_SYMBOL(xfrm_cfg_mutex);
 
+static DEFINE_SPINLOCK(xfrm_policy_sk_bundle_lock);
+static struct dst_entry *xfrm_policy_sk_bundles;
 static DEFINE_RWLOCK(xfrm_policy_lock);
 
 static DEFINE_RWLOCK(xfrm_policy_afinfo_lock);
@@ -50,6 +52,7 @@ static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
 static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
 static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
 static void xfrm_init_pmtu(struct dst_entry *dst);
+static int stale_bundle(struct dst_entry *dst);
 
 static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
                                                 int dir);
@@ -277,8 +280,6 @@ void xfrm_policy_destroy(struct xfrm_policy *policy)
 {
         BUG_ON(!policy->walk.dead);
 
-        BUG_ON(policy->bundles);
-
         if (del_timer(&policy->timer))
                 BUG();
 
@@ -289,12 +290,7 @@ EXPORT_SYMBOL(xfrm_policy_destroy);
 
 static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
 {
-        struct dst_entry *dst;
-
-        while ((dst = policy->bundles) != NULL) {
-                policy->bundles = dst->next;
-                dst_free(dst);
-        }
+        atomic_inc(&policy->genid);
 
         if (del_timer(&policy->timer))
                 atomic_dec(&policy->refcnt);
@@ -572,7 +568,6 @@ int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
         struct xfrm_policy *delpol;
         struct hlist_head *chain;
         struct hlist_node *entry, *newpos;
-        struct dst_entry *gc_list;
         u32 mark = policy->mark.v & policy->mark.m;
 
         write_lock_bh(&xfrm_policy_lock);
@@ -622,34 +617,6 @@ int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
         else if (xfrm_bydst_should_resize(net, dir, NULL))
                 schedule_work(&net->xfrm.policy_hash_work);
 
-        read_lock_bh(&xfrm_policy_lock);
-        gc_list = NULL;
-        entry = &policy->bydst;
-        hlist_for_each_entry_continue(policy, entry, bydst) {
-                struct dst_entry *dst;
-
-                write_lock(&policy->lock);
-                dst = policy->bundles;
-                if (dst) {
-                        struct dst_entry *tail = dst;
-                        while (tail->next)
-                                tail = tail->next;
-                        tail->next = gc_list;
-                        gc_list = dst;
-
-                        policy->bundles = NULL;
-                }
-                write_unlock(&policy->lock);
-        }
-        read_unlock_bh(&xfrm_policy_lock);
-
-        while (gc_list) {
-                struct dst_entry *dst = gc_list;
-
-                gc_list = dst->next;
-                dst_free(dst);
-        }
-
         return 0;
 }
 EXPORT_SYMBOL(xfrm_policy_insert);
@@ -998,6 +965,19 @@ fail:
         return ret;
 }
 
+static struct xfrm_policy *
+__xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family, u8 dir)
+{
+#ifdef CONFIG_XFRM_SUB_POLICY
+        struct xfrm_policy *pol;
+
+        pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_SUB, fl, family, dir);
+        if (pol != NULL)
+                return pol;
+#endif
+        return xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_MAIN, fl, family, dir);
+}
+
 static struct flow_cache_object *
 xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family,
                    u8 dir, struct flow_cache_object *old_obj, void *ctx)
@@ -1007,21 +987,10 @@ xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family,
         if (old_obj)
                 xfrm_pol_put(container_of(old_obj, struct xfrm_policy, flo));
 
-#ifdef CONFIG_XFRM_SUB_POLICY
-        pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_SUB, fl, family, dir);
-        if (IS_ERR(pol))
+        pol = __xfrm_policy_lookup(net, fl, family, dir);
+        if (IS_ERR_OR_NULL(pol))
                 return ERR_CAST(pol);
-        if (pol)
-                goto found;
-#endif
-        pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_MAIN, fl, family, dir);
-        if (IS_ERR(pol))
-                return ERR_CAST(pol);
-        if (pol)
-                goto found;
-        return NULL;
 
-found:
         /* Resolver returns two references:
          * one for cache and one for caller of flow_cache_lookup() */
         xfrm_pol_hold(pol);
@@ -1313,18 +1282,6 @@ xfrm_tmpl_resolve(struct xfrm_policy **pols, int npols, struct flowi *fl,
  * still valid.
  */
 
-static struct dst_entry *
-xfrm_find_bundle(struct flowi *fl, struct xfrm_policy *policy, unsigned short family)
-{
-        struct dst_entry *x;
-        struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
-        if (unlikely(afinfo == NULL))
-                return ERR_PTR(-EINVAL);
-        x = afinfo->find_bundle(fl, policy);
-        xfrm_policy_put_afinfo(afinfo);
-        return x;
-}
-
 static inline int xfrm_get_tos(struct flowi *fl, int family)
 {
         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
@@ -1340,6 +1297,54 @@ static inline int xfrm_get_tos(struct flowi *fl, int family)
         return tos;
 }
 
+static struct flow_cache_object *xfrm_bundle_flo_get(struct flow_cache_object *flo)
+{
+        struct xfrm_dst *xdst = container_of(flo, struct xfrm_dst, flo);
+        struct dst_entry *dst = &xdst->u.dst;
+
+        if (xdst->route == NULL) {
+                /* Dummy bundle - if it has xfrms we were not
+                 * able to build bundle as template resolution failed.
+                 * It means we need to try again resolving. */
+                if (xdst->num_xfrms > 0)
+                        return NULL;
+        } else {
+                /* Real bundle */
+                if (stale_bundle(dst))
+                        return NULL;
+        }
+
+        dst_hold(dst);
+        return flo;
+}
+
+static int xfrm_bundle_flo_check(struct flow_cache_object *flo)
+{
+        struct xfrm_dst *xdst = container_of(flo, struct xfrm_dst, flo);
+        struct dst_entry *dst = &xdst->u.dst;
+
+        if (!xdst->route)
+                return 0;
+        if (stale_bundle(dst))
+                return 0;
+
+        return 1;
+}
+
+static void xfrm_bundle_flo_delete(struct flow_cache_object *flo)
+{
+        struct xfrm_dst *xdst = container_of(flo, struct xfrm_dst, flo);
+        struct dst_entry *dst = &xdst->u.dst;
+
+        dst_free(dst);
+}
+
+static const struct flow_cache_ops xfrm_bundle_fc_ops = {
+        .get = xfrm_bundle_flo_get,
+        .check = xfrm_bundle_flo_check,
+        .delete = xfrm_bundle_flo_delete,
+};
+
 static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family)
 {
         struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
@@ -1362,9 +1367,10 @@ static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family)
                 BUG();
         }
         xdst = dst_alloc(dst_ops) ?: ERR_PTR(-ENOBUFS);
-
         xfrm_policy_put_afinfo(afinfo);
 
+        xdst->flo.ops = &xfrm_bundle_fc_ops;
+
         return xdst;
 }
 
@@ -1402,6 +1408,7 @@ static inline int xfrm_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
         return err;
 }
 
+
 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  * all the metrics... Shortly, bundle a bundle.
  */
@@ -1465,7 +1472,7 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
                         dst_hold(dst);
 
                 dst1->xfrm = xfrm[i];
-                xdst->genid = xfrm[i]->genid;
+                xdst->xfrm_genid = xfrm[i]->genid;
 
                 dst1->obsolete = -1;
                 dst1->flags |= DST_HOST;
@@ -1558,7 +1565,186 @@ xfrm_dst_update_origin(struct dst_entry *dst, struct flowi *fl)
 #endif
 }
 
-static int stale_bundle(struct dst_entry *dst);
+static int xfrm_expand_policies(struct flowi *fl, u16 family,
+                                struct xfrm_policy **pols,
+                                int *num_pols, int *num_xfrms)
+{
+        int i;
+
+        if (*num_pols == 0 || !pols[0]) {
+                *num_pols = 0;
+                *num_xfrms = 0;
+                return 0;
+        }
+        if (IS_ERR(pols[0]))
+                return PTR_ERR(pols[0]);
+
+        *num_xfrms = pols[0]->xfrm_nr;
+
+#ifdef CONFIG_XFRM_SUB_POLICY
+        if (pols[0] && pols[0]->action == XFRM_POLICY_ALLOW &&
+            pols[0]->type != XFRM_POLICY_TYPE_MAIN) {
+                pols[1] = xfrm_policy_lookup_bytype(xp_net(pols[0]),
+                                                    XFRM_POLICY_TYPE_MAIN,
+                                                    fl, family,
+                                                    XFRM_POLICY_OUT);
+                if (pols[1]) {
+                        if (IS_ERR(pols[1])) {
+                                xfrm_pols_put(pols, *num_pols);
+                                return PTR_ERR(pols[1]);
+                        }
+                        (*num_pols) ++;
+                        (*num_xfrms) += pols[1]->xfrm_nr;
+                }
+        }
+#endif
+        for (i = 0; i < *num_pols; i++) {
+                if (pols[i]->action != XFRM_POLICY_ALLOW) {
+                        *num_xfrms = -1;
+                        break;
+                }
+        }
+
+        return 0;
+
+}
+
+static struct xfrm_dst *
+xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols,
+                               struct flowi *fl, u16 family,
+                               struct dst_entry *dst_orig)
+{
+        struct net *net = xp_net(pols[0]);
+        struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
+        struct dst_entry *dst;
+        struct xfrm_dst *xdst;
+        int err;
+
+        /* Try to instantiate a bundle */
+        err = xfrm_tmpl_resolve(pols, num_pols, fl, xfrm, family);
+        if (err < 0) {
+                if (err != -EAGAIN)
+                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
+                return ERR_PTR(err);
+        }
+
+        dst = xfrm_bundle_create(pols[0], xfrm, err, fl, dst_orig);
+        if (IS_ERR(dst)) {
+                XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLEGENERROR);
+                return ERR_CAST(dst);
+        }
+
+        xdst = (struct xfrm_dst *)dst;
+        xdst->num_xfrms = err;
+        if (num_pols > 1)
+                err = xfrm_dst_update_parent(dst, &pols[1]->selector);
+        else
+                err = xfrm_dst_update_origin(dst, fl);
+        if (unlikely(err)) {
+                dst_free(dst);
+                XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLECHECKERROR);
+                return ERR_PTR(err);
+        }
+
+        xdst->num_pols = num_pols;
+        memcpy(xdst->pols, pols, sizeof(struct xfrm_policy*) * num_pols);
+        xdst->policy_genid = atomic_read(&pols[0]->genid);
+
+        return xdst;
+}
+
+static struct flow_cache_object *
+xfrm_bundle_lookup(struct net *net, struct flowi *fl, u16 family, u8 dir,
+                   struct flow_cache_object *oldflo, void *ctx)
+{
+        struct dst_entry *dst_orig = (struct dst_entry *)ctx;
+        struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
+        struct xfrm_dst *xdst, *new_xdst;
+        int num_pols = 0, num_xfrms = 0, i, err, pol_dead;
+
+        /* Check if the policies from old bundle are usable */
+        xdst = NULL;
+        if (oldflo) {
+                xdst = container_of(oldflo, struct xfrm_dst, flo);
+                num_pols = xdst->num_pols;
+                num_xfrms = xdst->num_xfrms;
+                pol_dead = 0;
+                for (i = 0; i < num_pols; i++) {
+                        pols[i] = xdst->pols[i];
+                        pol_dead |= pols[i]->walk.dead;
+                }
+                if (pol_dead) {
+                        dst_free(&xdst->u.dst);
+                        xdst = NULL;
+                        num_pols = 0;
+                        num_xfrms = 0;
+                        oldflo = NULL;
+                }
+        }
+
+        /* Resolve policies to use if we couldn't get them from
+         * previous cache entry */
+        if (xdst == NULL) {
+                num_pols = 1;
+                pols[0] = __xfrm_policy_lookup(net, fl, family, dir);
+                err = xfrm_expand_policies(fl, family, pols,
+                                           &num_pols, &num_xfrms);
+                if (err < 0)
+                        goto inc_error;
+                if (num_pols == 0)
+                        return NULL;
+                if (num_xfrms <= 0)
+                        goto make_dummy_bundle;
+        }
+
+        new_xdst = xfrm_resolve_and_create_bundle(pols, num_pols, fl, family, dst_orig);
+        if (IS_ERR(new_xdst)) {
+                err = PTR_ERR(new_xdst);
+                if (err != -EAGAIN)
+                        goto error;
+                if (oldflo == NULL)
+                        goto make_dummy_bundle;
+                dst_hold(&xdst->u.dst);
+                return oldflo;
+        }
+
+        /* Kill the previous bundle */
+        if (xdst) {
+                /* The policies were stolen for newly generated bundle */
+                xdst->num_pols = 0;
+                dst_free(&xdst->u.dst);
+        }
+
+        /* Flow cache does not have reference, it dst_free()'s,
+         * but we do need to return one reference for original caller */
+        dst_hold(&new_xdst->u.dst);
+        return &new_xdst->flo;
+
+make_dummy_bundle:
+        /* We found policies, but there's no bundles to instantiate:
+         * either because the policy blocks, has no transformations or
+         * we could not build template (no xfrm_states).*/
+        xdst = xfrm_alloc_dst(net, family);
+        if (IS_ERR(xdst)) {
+                xfrm_pols_put(pols, num_pols);
+                return ERR_CAST(xdst);
+        }
+        xdst->num_pols = num_pols;
+        xdst->num_xfrms = num_xfrms;
+        memcpy(xdst->pols, pols, sizeof(struct xfrm_policy*) * num_pols);
+
+        dst_hold(&xdst->u.dst);
+        return &xdst->flo;
+
+inc_error:
+        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
+error:
+        if (xdst != NULL)
+                dst_free(&xdst->u.dst);
+        else
+                xfrm_pols_put(pols, num_pols);
+        return ERR_PTR(err);
+}
 
 /* Main function: finds/creates a bundle for given flow.
  *
@@ -1568,248 +1754,152 @@ static int stale_bundle(struct dst_entry *dst);
 int __xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl,
                   struct sock *sk, int flags)
 {
-        struct xfrm_policy *policy;
         struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
-        int npols;
-        int pol_dead;
-        int xfrm_nr;
-        int pi;
-        struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
-        struct dst_entry *dst, *dst_orig = *dst_p;
-        int nx = 0;
-        int err;
-        u32 genid;
-        u16 family;
+        struct flow_cache_object *flo;
+        struct xfrm_dst *xdst;
+        struct dst_entry *dst, *dst_orig = *dst_p, *route;
+        u16 family = dst_orig->ops->family;
         u8 dir = policy_to_flow_dir(XFRM_POLICY_OUT);
+        int i, err, num_pols, num_xfrms, drop_pols = 0;
 
 restart:
-        genid = atomic_read(&flow_cache_genid);
-        policy = NULL;
-        for (pi = 0; pi < ARRAY_SIZE(pols); pi++)
-                pols[pi] = NULL;
-        npols = 0;
-        pol_dead = 0;
-        xfrm_nr = 0;
+        dst = NULL;
+        xdst = NULL;
+        route = NULL;
 
         if (sk && sk->sk_policy[XFRM_POLICY_OUT]) {
-                policy = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl);
-                err = PTR_ERR(policy);
-                if (IS_ERR(policy)) {
-                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
+                num_pols = 1;
+                pols[0] = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl);
+                err = xfrm_expand_policies(fl, family, pols,
+                                           &num_pols, &num_xfrms);
+                if (err < 0)
                         goto dropdst;
+
+                if (num_pols) {
+                        if (num_xfrms <= 0) {
+                                drop_pols = num_pols;
+                                goto no_transform;
+                        }
+
+                        xdst = xfrm_resolve_and_create_bundle(
+                                        pols, num_pols, fl,
+                                        family, dst_orig);
+                        if (IS_ERR(xdst)) {
+                                xfrm_pols_put(pols, num_pols);
+                                err = PTR_ERR(xdst);
+                                goto dropdst;
+                        }
+
+                        spin_lock_bh(&xfrm_policy_sk_bundle_lock);
+                        xdst->u.dst.next = xfrm_policy_sk_bundles;
+                        xfrm_policy_sk_bundles = &xdst->u.dst;
+                        spin_unlock_bh(&xfrm_policy_sk_bundle_lock);
+
+                        route = xdst->route;
                 }
         }
 
-        if (!policy) {
-                struct flow_cache_object *flo;
-
+        if (xdst == NULL) {
                 /* To accelerate a bit...  */
                 if ((dst_orig->flags & DST_NOXFRM) ||
                     !net->xfrm.policy_count[XFRM_POLICY_OUT])
                         goto nopol;
 
-                flo = flow_cache_lookup(net, fl, dst_orig->ops->family,
-                                        dir, xfrm_policy_lookup, NULL);
-                err = PTR_ERR(flo);
+                flo = flow_cache_lookup(net, fl, family, dir,
+                                        xfrm_bundle_lookup, dst_orig);
+                if (flo == NULL)
+                        goto nopol;
                 if (IS_ERR(flo)) {
-                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
+                        err = PTR_ERR(flo);
                         goto dropdst;
                 }
-                if (flo)
-                        policy = container_of(flo, struct xfrm_policy, flo);
-                else
-                        policy = NULL;
+                xdst = container_of(flo, struct xfrm_dst, flo);
+
+                num_pols = xdst->num_pols;
+                num_xfrms = xdst->num_xfrms;
+                memcpy(pols, xdst->pols, sizeof(struct xfrm_policy*) * num_pols);
+                route = xdst->route;
+        }
+
+        dst = &xdst->u.dst;
+        if (route == NULL && num_xfrms > 0) {
+                /* The only case when xfrm_bundle_lookup() returns a
+                 * bundle with null route, is when the template could
+                 * not be resolved. It means policies are there, but
+                 * bundle could not be created, since we don't yet
+                 * have the xfrm_state's. We need to wait for KM to
+                 * negotiate new SA's or bail out with error.*/
+                if (net->xfrm.sysctl_larval_drop) {
+                        /* EREMOTE tells the caller to generate
+                         * a one-shot blackhole route. */
+                        dst_release(dst);
+                        xfrm_pols_put(pols, num_pols);
+                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
+                        return -EREMOTE;
+                }
+                if (flags & XFRM_LOOKUP_WAIT) {
+                        DECLARE_WAITQUEUE(wait, current);
+
+                        add_wait_queue(&net->xfrm.km_waitq, &wait);
+                        set_current_state(TASK_INTERRUPTIBLE);
+                        schedule();
+                        set_current_state(TASK_RUNNING);
+                        remove_wait_queue(&net->xfrm.km_waitq, &wait);
+
+                        if (!signal_pending(current)) {
+                                dst_release(dst);
+                                goto restart;
+                        }
+
+                        err = -ERESTART;
+                } else
+                        err = -EAGAIN;
+
+                XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
+                goto error;
         }
 
-        if (!policy)
+no_transform:
+        if (num_pols == 0)
                 goto nopol;
 
-        family = dst_orig->ops->family;
-        pols[0] = policy;
-        npols ++;
-        xfrm_nr += pols[0]->xfrm_nr;
-
-        err = -ENOENT;
-        if ((flags & XFRM_LOOKUP_ICMP) && !(policy->flags & XFRM_POLICY_ICMP))
+        if ((flags & XFRM_LOOKUP_ICMP) &&
+            !(pols[0]->flags & XFRM_POLICY_ICMP)) {
+                err = -ENOENT;
                 goto error;
+        }
 
-        policy->curlft.use_time = get_seconds();
+        for (i = 0; i < num_pols; i++)
+                pols[i]->curlft.use_time = get_seconds();
 
-        switch (policy->action) {
-        default:
-        case XFRM_POLICY_BLOCK:
+        if (num_xfrms < 0) {
                 /* Prohibit the flow */
                 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLBLOCK);
                 err = -EPERM;
                 goto error;
-
-        case XFRM_POLICY_ALLOW:
-#ifndef CONFIG_XFRM_SUB_POLICY
-                if (policy->xfrm_nr == 0) {
-                        /* Flow passes not transformed. */
-                        xfrm_pol_put(policy);
-                        return 0;
-                }
-#endif
-
-                /* Try to find matching bundle.
-                 *
-                 * LATER: help from flow cache. It is optional, this
-                 * is required only for output policy.
-                 */
-                dst = xfrm_find_bundle(fl, policy, family);
-                if (IS_ERR(dst)) {
-                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLECHECKERROR);
-                        err = PTR_ERR(dst);
-                        goto error;
-                }
-
-                if (dst)
-                        break;
-
-#ifdef CONFIG_XFRM_SUB_POLICY
-                if (pols[0]->type != XFRM_POLICY_TYPE_MAIN) {
-                        pols[1] = xfrm_policy_lookup_bytype(net,
-                                                            XFRM_POLICY_TYPE_MAIN,
-                                                            fl, family,
-                                                            XFRM_POLICY_OUT);
-                        if (pols[1]) {
-                                if (IS_ERR(pols[1])) {
-                                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
-                                        err = PTR_ERR(pols[1]);
-                                        goto error;
-                                }
-                                if (pols[1]->action == XFRM_POLICY_BLOCK) {
-                                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLBLOCK);
-                                        err = -EPERM;
-                                        goto error;
-                                }
-                                npols ++;
-                                xfrm_nr += pols[1]->xfrm_nr;
-                        }
-                }
-
-                /*
-                 * Because neither flowi nor bundle information knows about
-                 * transformation template size. On more than one policy usage
-                 * we can realize whether all of them is bypass or not after
-                 * they are searched. See above not-transformed bypass
-                 * is surrounded by non-sub policy configuration, too.
-                 */
-                if (xfrm_nr == 0) {
-                        /* Flow passes not transformed. */
-                        xfrm_pols_put(pols, npols);
-                        return 0;
-                }
-
-#endif
-                nx = xfrm_tmpl_resolve(pols, npols, fl, xfrm, family);
-
-                if (unlikely(nx<0)) {
-                        err = nx;
-                        if (err == -EAGAIN && net->xfrm.sysctl_larval_drop) {
-                                /* EREMOTE tells the caller to generate
-                                 * a one-shot blackhole route.
-                                 */
-                                XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
-                                xfrm_pol_put(policy);
-                                return -EREMOTE;
-                        }
-                        if (err == -EAGAIN && (flags & XFRM_LOOKUP_WAIT)) {
-                                DECLARE_WAITQUEUE(wait, current);
-
-                                add_wait_queue(&net->xfrm.km_waitq, &wait);
-                                set_current_state(TASK_INTERRUPTIBLE);
-                                schedule();
-                                set_current_state(TASK_RUNNING);
-                                remove_wait_queue(&net->xfrm.km_waitq, &wait);
-
-                                nx = xfrm_tmpl_resolve(pols, npols, fl, xfrm, family);
-
-                                if (nx == -EAGAIN && signal_pending(current)) {
-                                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
-                                        err = -ERESTART;
-                                        goto error;
-                                }
-                                if (nx == -EAGAIN ||
-                                    genid != atomic_read(&flow_cache_genid)) {
-                                        xfrm_pols_put(pols, npols);
-                                        goto restart;
-                                }
-                                err = nx;
-                        }
-                        if (err < 0) {
-                                XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
-                                goto error;
-                        }
-                }
-                if (nx == 0) {
-                        /* Flow passes not transformed. */
-                        xfrm_pols_put(pols, npols);
-                        return 0;
-                }
-
-                dst = xfrm_bundle_create(policy, xfrm, nx, fl, dst_orig);
-                err = PTR_ERR(dst);
-                if (IS_ERR(dst)) {
-                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLEGENERROR);
-                        goto error;
-                }
-
-                for (pi = 0; pi < npols; pi++)
-                        pol_dead |= pols[pi]->walk.dead;
-
-                write_lock_bh(&policy->lock);
-                if (unlikely(pol_dead || stale_bundle(dst))) {
-                        /* Wow! While we worked on resolving, this
-                         * policy has gone. Retry. It is not paranoia,
-                         * we just cannot enlist new bundle to dead object.
-                         * We can't enlist stable bundles either.
-                         */
-                        write_unlock_bh(&policy->lock);
-                        dst_free(dst);
-
-                        if (pol_dead)
-                                XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLDEAD);
-                        else
-                                XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLECHECKERROR);
-                        err = -EHOSTUNREACH;
-                        goto error;
-                }
-
-                if (npols > 1)
-                        err = xfrm_dst_update_parent(dst, &pols[1]->selector);
-                else
-                        err = xfrm_dst_update_origin(dst, fl);
-                if (unlikely(err)) {
-                        write_unlock_bh(&policy->lock);
-                        dst_free(dst);
-                        XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLECHECKERROR);
-                        goto error;
-                }
-
-                dst->next = policy->bundles;
-                policy->bundles = dst;
-                dst_hold(dst);
-                write_unlock_bh(&policy->lock);
+        } else if (num_xfrms > 0) {
+                /* Flow transformed */
+                *dst_p = dst;
+                dst_release(dst_orig);
+        } else {
+                /* Flow passes untransformed */
+                dst_release(dst);
         }
-        *dst_p = dst;
-        dst_release(dst_orig);
-        xfrm_pols_put(pols, npols);
+ok:
+        xfrm_pols_put(pols, drop_pols);
         return 0;
 
+nopol:
+        if (!(flags & XFRM_LOOKUP_ICMP))
+                goto ok;
+        err = -ENOENT;
 error:
-        xfrm_pols_put(pols, npols);
+        dst_release(dst);
 dropdst:
         dst_release(dst_orig);
         *dst_p = NULL;
+        xfrm_pols_put(pols, drop_pols);
         return err;
-
-nopol:
-        err = -ENOENT;
-        if (flags & XFRM_LOOKUP_ICMP)
-                goto dropdst;
-        return 0;
 }
 EXPORT_SYMBOL(__xfrm_lookup);
 
@@ -2161,71 +2251,24 @@ static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
         return dst;
 }
 
-static void prune_one_bundle(struct xfrm_policy *pol, int (*func)(struct dst_entry *), struct dst_entry **gc_list_p)
-{
-        struct dst_entry *dst, **dstp;
-
-        write_lock(&pol->lock);
-        dstp = &pol->bundles;
-        while ((dst=*dstp) != NULL) {
-                if (func(dst)) {
-                        *dstp = dst->next;
-                        dst->next = *gc_list_p;
-                        *gc_list_p = dst;
-                } else {
-                        dstp = &dst->next;
-                }
-        }
-        write_unlock(&pol->lock);
-}
-
-static void xfrm_prune_bundles(struct net *net, int (*func)(struct dst_entry *))
+static void __xfrm_garbage_collect(struct net *net)
 {
-        struct dst_entry *gc_list = NULL;
-        int dir;
+        struct dst_entry *head, *next;
 
-        read_lock_bh(&xfrm_policy_lock);
-        for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
-                struct xfrm_policy *pol;
-                struct hlist_node *entry;
-                struct hlist_head *table;
-                int i;
+        flow_cache_flush();
 
-                hlist_for_each_entry(pol, entry,
-                                     &net->xfrm.policy_inexact[dir], bydst)
-                        prune_one_bundle(pol, func, &gc_list);
+        spin_lock_bh(&xfrm_policy_sk_bundle_lock);
+        head = xfrm_policy_sk_bundles;
+        xfrm_policy_sk_bundles = NULL;
+        spin_unlock_bh(&xfrm_policy_sk_bundle_lock);
 
-                table = net->xfrm.policy_bydst[dir].table;
-                for (i = net->xfrm.policy_bydst[dir].hmask; i >= 0; i--) {
-                        hlist_for_each_entry(pol, entry, table + i, bydst)
-                                prune_one_bundle(pol, func, &gc_list);
-                }
-        }
-        read_unlock_bh(&xfrm_policy_lock);
-
-        while (gc_list) {
-                struct dst_entry *dst = gc_list;
-                gc_list = dst->next;
-                dst_free(dst);
+        while (head) {
+                next = head->next;
+                dst_free(head);
+                head = next;
         }
 }
 
-static int unused_bundle(struct dst_entry *dst)
-{
-        return !atomic_read(&dst->__refcnt);
-}
-
-static void __xfrm_garbage_collect(struct net *net)
-{
-        xfrm_prune_bundles(net, unused_bundle);
-}
-
-static int xfrm_flush_bundles(struct net *net)
-{
-        xfrm_prune_bundles(net, stale_bundle);
-        return 0;
-}
-
 static void xfrm_init_pmtu(struct dst_entry *dst)
 {
         do {
@@ -2283,7 +2326,9 @@ int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
                         return 0;
                 if (dst->xfrm->km.state != XFRM_STATE_VALID)
                         return 0;
-                if (xdst->genid != dst->xfrm->genid)
+                if (xdst->xfrm_genid != dst->xfrm->genid)
+                        return 0;
+                if (xdst->policy_genid != atomic_read(&xdst->pols[0]->genid))
                         return 0;
 
                 if (strict && fl &&
@@ -2448,7 +2493,7 @@ static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void
 
         switch (event) {
         case NETDEV_DOWN:
-                xfrm_flush_bundles(dev_net(dev));
+                __xfrm_garbage_collect(dev_net(dev));
         }
         return NOTIFY_DONE;
 }
@@ -2780,7 +2825,6 @@ static int xfrm_policy_migrate(struct xfrm_policy *pol,
                                struct xfrm_migrate *m, int num_migrate)
 {
         struct xfrm_migrate *mp;
-        struct dst_entry *dst;
         int i, j, n = 0;
 
         write_lock_bh(&pol->lock);
@@ -2805,10 +2849,7 @@ static int xfrm_policy_migrate(struct xfrm_policy *pol,
                                sizeof(pol->xfrm_vec[i].saddr));
                         pol->xfrm_vec[i].encap_family = mp->new_family;
                         /* flush bundles */
-                        while ((dst = pol->bundles) != NULL) {
-                                pol->bundles = dst->next;
-                                dst_free(dst);
-                        }
+                        atomic_inc(&pol->genid);
                 }
         }