ip6mr: Align hash implementation to ipmr

Since commit 8fb472c09b9d ("ipmr: improve hash scalability") ipmr has
been using rhashtable as a basis for its mfc routes, but ip6mr is
currently still using the old private MFC hash implementation.

Align ip6mr to the current ipmr implementation.

Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/mroute6.h b/include/linux/mroute6.h
index e1b9fb06e1ea6609dcc4f2a2aada6329a9499ced..e2dac199861e354b069913fdbce1bde763da6c62 100644 (file)
--- a/include/linux/mroute6.h
+++ b/include/linux/mroute6.h
@@ -8,6 +8,7 @@
 #include <net/net_namespace.h>
 #include <uapi/linux/mroute6.h>
 #include <linux/mroute_base.h>
+#include <linux/rhashtable.h>
 
 #ifdef CONFIG_IPV6_MROUTE
 static inline int ip6_mroute_opt(int opt)
@@ -65,10 +66,20 @@ static inline void ip6_mr_cleanup(void)
 
 #define VIFF_STATIC 0x8000
 
+struct mfc6_cache_cmp_arg {
+       struct in6_addr mf6c_mcastgrp;
+       struct in6_addr mf6c_origin;
+};
+
 struct mfc6_cache {
-       struct list_head list;
-       struct in6_addr mf6c_mcastgrp;                  /* Group the entry belongs to   */
-       struct in6_addr mf6c_origin;                    /* Source of packet             */
+       struct rhlist_head mnode;
+       union {
+               struct {
+                       struct in6_addr mf6c_mcastgrp;
+                       struct in6_addr mf6c_origin;
+               };
+               struct mfc6_cache_cmp_arg cmparg;
+       };
        mifi_t mf6c_parent;                     /* Source interface             */
        int mfc_flags;                          /* Flags on line                */
 
@@ -88,22 +99,13 @@ struct mfc6_cache {
                        unsigned char ttls[MAXMIFS];    /* TTL thresholds               */
                } res;
        } mfc_un;
+       struct list_head list;
+       struct rcu_head rcu;
 };
 
 #define MFC_STATIC             1
 #define MFC_NOTIFY             2
 
-#define MFC6_LINES             64
-
-#define MFC6_HASH(a, g) (((__force u32)(a)->s6_addr32[0] ^ \
-                         (__force u32)(a)->s6_addr32[1] ^ \
-                         (__force u32)(a)->s6_addr32[2] ^ \
-                         (__force u32)(a)->s6_addr32[3] ^ \
-                         (__force u32)(g)->s6_addr32[0] ^ \
-                         (__force u32)(g)->s6_addr32[1] ^ \
-                         (__force u32)(g)->s6_addr32[2] ^ \
-                         (__force u32)(g)->s6_addr32[3]) % MFC6_LINES)
-
 #define MFC_ASSERT_THRESH (3*HZ)               /* Maximal freq. of asserts */
 
 struct rtmsg;

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index a0e297ddca6e8ac9b9cec6a2c35de412824764c3..6f0b7f4894b28743528b878190a8a6c0cebb946b 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -61,8 +61,9 @@ struct mr6_table {
        struct sock __rcu       *mroute6_sk;
        struct timer_list       ipmr_expire_timer;
        struct list_head        mfc6_unres_queue;
-       struct list_head        mfc6_cache_array[MFC6_LINES];
        struct vif_device       vif6_table[MAXMIFS];
+       struct rhltable         mfc6_hash;
+       struct list_head        mfc6_cache_list;
        int                     maxvif;
        atomic_t                cache_resolve_queue_len;
        bool                    mroute_do_assert;
@@ -299,10 +300,29 @@ static void __net_exit ip6mr_rules_exit(struct net *net)
 }
 #endif
 
+static int ip6mr_hash_cmp(struct rhashtable_compare_arg *arg,
+                         const void *ptr)
+{
+       const struct mfc6_cache_cmp_arg *cmparg = arg->key;
+       struct mfc6_cache *c = (struct mfc6_cache *)ptr;
+
+       return !ipv6_addr_equal(&c->mf6c_mcastgrp, &cmparg->mf6c_mcastgrp) ||
+              !ipv6_addr_equal(&c->mf6c_origin, &cmparg->mf6c_origin);
+}
+
+static const struct rhashtable_params ip6mr_rht_params = {
+       .head_offset = offsetof(struct mfc6_cache, mnode),
+       .key_offset = offsetof(struct mfc6_cache, cmparg),
+       .key_len = sizeof(struct mfc6_cache_cmp_arg),
+       .nelem_hint = 3,
+       .locks_mul = 1,
+       .obj_cmpfn = ip6mr_hash_cmp,
+       .automatic_shrinking = true,
+};
+
 static struct mr6_table *ip6mr_new_table(struct net *net, u32 id)
 {
        struct mr6_table *mrt;
-       unsigned int i;
 
        mrt = ip6mr_get_table(net, id);
        if (mrt)
@@ -314,10 +334,8 @@ static struct mr6_table *ip6mr_new_table(struct net *net, u32 id)
        mrt->id = id;
        write_pnet(&mrt->net, net);
 
-       /* Forwarding cache */
-       for (i = 0; i < MFC6_LINES; i++)
-               INIT_LIST_HEAD(&mrt->mfc6_cache_array[i]);
-
+       rhltable_init(&mrt->mfc6_hash, &ip6mr_rht_params);
+       INIT_LIST_HEAD(&mrt->mfc6_cache_list);
        INIT_LIST_HEAD(&mrt->mfc6_unres_queue);
 
        timer_setup(&mrt->ipmr_expire_timer, ipmr_expire_process, 0);
@@ -335,6 +353,7 @@ static void ip6mr_free_table(struct mr6_table *mrt)
 {
        del_timer_sync(&mrt->ipmr_expire_timer);
        mroute_clean_tables(mrt, true);
+       rhltable_destroy(&mrt->mfc6_hash);
        kfree(mrt);
 }
 
@@ -344,7 +363,6 @@ struct ipmr_mfc_iter {
        struct seq_net_private p;
        struct mr6_table *mrt;
        struct list_head *cache;
-       int ct;
 };
 
 
@@ -354,14 +372,12 @@ static struct mfc6_cache *ipmr_mfc_seq_idx(struct net *net,
        struct mr6_table *mrt = it->mrt;
        struct mfc6_cache *mfc;
 
-       read_lock(&mrt_lock);
-       for (it->ct = 0; it->ct < MFC6_LINES; it->ct++) {
-               it->cache = &mrt->mfc6_cache_array[it->ct];
-               list_for_each_entry(mfc, it->cache, list)
-                       if (pos-- == 0)
-                               return mfc;
-       }
-       read_unlock(&mrt_lock);
+       rcu_read_lock();
+       it->cache = &mrt->mfc6_cache_list;
+       list_for_each_entry_rcu(mfc, &mrt->mfc6_cache_list, list)
+               if (pos-- == 0)
+                       return mfc;
+       rcu_read_unlock();
 
        spin_lock_bh(&mfc_unres_lock);
        it->cache = &mrt->mfc6_unres_queue;
@@ -517,19 +533,9 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
        if (it->cache == &mrt->mfc6_unres_queue)
                goto end_of_list;
 
-       BUG_ON(it->cache != &mrt->mfc6_cache_array[it->ct]);
-
-       while (++it->ct < MFC6_LINES) {
-               it->cache = &mrt->mfc6_cache_array[it->ct];
-               if (list_empty(it->cache))
-                       continue;
-               return list_first_entry(it->cache, struct mfc6_cache, list);
-       }
-
        /* exhausted cache_array, show unresolved */
-       read_unlock(&mrt_lock);
+       rcu_read_unlock();
        it->cache = &mrt->mfc6_unres_queue;
-       it->ct = 0;
 
        spin_lock_bh(&mfc_unres_lock);
        if (!list_empty(it->cache))
@@ -549,8 +555,8 @@ static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
 
        if (it->cache == &mrt->mfc6_unres_queue)
                spin_unlock_bh(&mfc_unres_lock);
-       else if (it->cache == &mrt->mfc6_cache_array[it->ct])
-               read_unlock(&mrt_lock);
+       else if (it->cache == &mrt->mfc6_cache_list)
+               rcu_read_unlock();
 }
 
 static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
@@ -827,11 +833,18 @@ static int mif6_delete(struct mr6_table *mrt, int vifi, int notify,
        return 0;
 }
 
-static inline void ip6mr_cache_free(struct mfc6_cache *c)
+static inline void ip6mr_cache_free_rcu(struct rcu_head *head)
 {
+       struct mfc6_cache *c = container_of(head, struct mfc6_cache, rcu);
+
        kmem_cache_free(mrt_cachep, c);
 }
 
+static inline void ip6mr_cache_free(struct mfc6_cache *c)
+{
+       call_rcu(&c->rcu, ip6mr_cache_free_rcu);
+}
+
 /* Destroy an unresolved cache entry, killing queued skbs
    and reporting error to netlink readers.
  */
@@ -1002,14 +1015,17 @@ static struct mfc6_cache *ip6mr_cache_find(struct mr6_table *mrt,
                                           const struct in6_addr *origin,
                                           const struct in6_addr *mcastgrp)
 {
-       int line = MFC6_HASH(mcastgrp, origin);
+       struct mfc6_cache_cmp_arg arg = {
+               .mf6c_origin = *origin,
+               .mf6c_mcastgrp = *mcastgrp,
+       };
+       struct rhlist_head *tmp, *list;
        struct mfc6_cache *c;
 
-       list_for_each_entry(c, &mrt->mfc6_cache_array[line], list) {
-               if (ipv6_addr_equal(&c->mf6c_origin, origin) &&
-                   ipv6_addr_equal(&c->mf6c_mcastgrp, mcastgrp))
-                       return c;
-       }
+       list = rhltable_lookup(&mrt->mfc6_hash, &arg, ip6mr_rht_params);
+       rhl_for_each_entry_rcu(c, tmp, list, mnode)
+               return c;
+
        return NULL;
 }
 
@@ -1017,13 +1033,16 @@ static struct mfc6_cache *ip6mr_cache_find(struct mr6_table *mrt,
 static struct mfc6_cache *ip6mr_cache_find_any_parent(struct mr6_table *mrt,
                                                      mifi_t mifi)
 {
-       int line = MFC6_HASH(&in6addr_any, &in6addr_any);
+       struct mfc6_cache_cmp_arg arg = {
+               .mf6c_origin = in6addr_any,
+               .mf6c_mcastgrp = in6addr_any,
+       };
+       struct rhlist_head *tmp, *list;
        struct mfc6_cache *c;
 
-       list_for_each_entry(c, &mrt->mfc6_cache_array[line], list)
-               if (ipv6_addr_any(&c->mf6c_origin) &&
-                   ipv6_addr_any(&c->mf6c_mcastgrp) &&
-                   (c->mfc_un.res.ttls[mifi] < 255))
+       list = rhltable_lookup(&mrt->mfc6_hash, &arg, ip6mr_rht_params);
+       rhl_for_each_entry_rcu(c, tmp, list, mnode)
+               if (c->mfc_un.res.ttls[mifi] < 255)
                        return c;
 
        return NULL;
@@ -1034,29 +1053,53 @@ static struct mfc6_cache *ip6mr_cache_find_any(struct mr6_table *mrt,
                                               struct in6_addr *mcastgrp,
                                               mifi_t mifi)
 {
-       int line = MFC6_HASH(mcastgrp, &in6addr_any);
+       struct mfc6_cache_cmp_arg arg = {
+               .mf6c_origin = in6addr_any,
+               .mf6c_mcastgrp = *mcastgrp,
+       };
+       struct rhlist_head *tmp, *list;
        struct mfc6_cache *c, *proxy;
 
        if (ipv6_addr_any(mcastgrp))
                goto skip;
 
-       list_for_each_entry(c, &mrt->mfc6_cache_array[line], list)
-               if (ipv6_addr_any(&c->mf6c_origin) &&
-                   ipv6_addr_equal(&c->mf6c_mcastgrp, mcastgrp)) {
-                       if (c->mfc_un.res.ttls[mifi] < 255)
-                               return c;
-
-                       /* It's ok if the mifi is part of the static tree */
-                       proxy = ip6mr_cache_find_any_parent(mrt,
-                                                           c->mf6c_parent);
-                       if (proxy && proxy->mfc_un.res.ttls[mifi] < 255)
-                               return c;
-               }
+       list = rhltable_lookup(&mrt->mfc6_hash, &arg, ip6mr_rht_params);
+       rhl_for_each_entry_rcu(c, tmp, list, mnode) {
+               if (c->mfc_un.res.ttls[mifi] < 255)
+                       return c;
+
+               /* It's ok if the mifi is part of the static tree */
+               proxy = ip6mr_cache_find_any_parent(mrt, c->mf6c_parent);
+               if (proxy && proxy->mfc_un.res.ttls[mifi] < 255)
+                       return c;
+       }
 
 skip:
        return ip6mr_cache_find_any_parent(mrt, mifi);
 }
 
+/* Look for a (S,G,iif) entry if parent != -1 */
+static struct mfc6_cache *
+ip6mr_cache_find_parent(struct mr6_table *mrt,
+                       const struct in6_addr *origin,
+                       const struct in6_addr *mcastgrp,
+                       int parent)
+{
+       struct mfc6_cache_cmp_arg arg = {
+               .mf6c_origin = *origin,
+               .mf6c_mcastgrp = *mcastgrp,
+       };
+       struct rhlist_head *tmp, *list;
+       struct mfc6_cache *c;
+
+       list = rhltable_lookup(&mrt->mfc6_hash, &arg, ip6mr_rht_params);
+       rhl_for_each_entry_rcu(c, tmp, list, mnode)
+               if (parent == -1 || parent == c->mf6c_parent)
+                       return c;
+
+       return NULL;
+}
+
 /*
  *     Allocate a multicast cache entry
  */
@@ -1296,26 +1339,21 @@ ip6mr_cache_unresolved(struct mr6_table *mrt, mifi_t mifi, struct sk_buff *skb)
 static int ip6mr_mfc_delete(struct mr6_table *mrt, struct mf6cctl *mfc,
                            int parent)
 {
-       int line;
-       struct mfc6_cache *c, *next;
-
-       line = MFC6_HASH(&mfc->mf6cc_mcastgrp.sin6_addr, &mfc->mf6cc_origin.sin6_addr);
+       struct mfc6_cache *c;
 
-       list_for_each_entry_safe(c, next, &mrt->mfc6_cache_array[line], list) {
-               if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&
-                   ipv6_addr_equal(&c->mf6c_mcastgrp,
-                                   &mfc->mf6cc_mcastgrp.sin6_addr) &&
-                   (parent == -1 || parent == c->mf6c_parent)) {
-                       write_lock_bh(&mrt_lock);
-                       list_del(&c->list);
-                       write_unlock_bh(&mrt_lock);
+       /* The entries are added/deleted only under RTNL */
+       rcu_read_lock();
+       c = ip6mr_cache_find_parent(mrt, &mfc->mf6cc_origin.sin6_addr,
+                                   &mfc->mf6cc_mcastgrp.sin6_addr, parent);
+       rcu_read_unlock();
+       if (!c)
+               return -ENOENT;
+       rhltable_remove(&mrt->mfc6_hash, &c->mnode, ip6mr_rht_params);
+       list_del_rcu(&c->list);
 
-                       mr6_netlink_event(mrt, c, RTM_DELROUTE);
-                       ip6mr_cache_free(c);
-                       return 0;
-               }
-       }
-       return -ENOENT;
+       mr6_netlink_event(mrt, c, RTM_DELROUTE);
+       ip6mr_cache_free(c);
+       return 0;
 }
 
 static int ip6mr_device_event(struct notifier_block *this,
@@ -1448,11 +1486,10 @@ void ip6_mr_cleanup(void)
 static int ip6mr_mfc_add(struct net *net, struct mr6_table *mrt,
                         struct mf6cctl *mfc, int mrtsock, int parent)
 {
-       bool found = false;
-       int line;
-       struct mfc6_cache *uc, *c;
        unsigned char ttls[MAXMIFS];
-       int i;
+       struct mfc6_cache *uc, *c;
+       bool found;
+       int i, err;
 
        if (mfc->mf6cc_parent >= MAXMIFS)
                return -ENFILE;
@@ -1461,22 +1498,14 @@ static int ip6mr_mfc_add(struct net *net, struct mr6_table *mrt,
        for (i = 0; i < MAXMIFS; i++) {
                if (IF_ISSET(i, &mfc->mf6cc_ifset))
                        ttls[i] = 1;
-
-       }
-
-       line = MFC6_HASH(&mfc->mf6cc_mcastgrp.sin6_addr, &mfc->mf6cc_origin.sin6_addr);
-
-       list_for_each_entry(c, &mrt->mfc6_cache_array[line], list) {
-               if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&
-                   ipv6_addr_equal(&c->mf6c_mcastgrp,
-                                   &mfc->mf6cc_mcastgrp.sin6_addr) &&
-                   (parent == -1 || parent == mfc->mf6cc_parent)) {
-                       found = true;
-                       break;
-               }
        }
 
-       if (found) {
+       /* The entries are added/deleted only under RTNL */
+       rcu_read_lock();
+       c = ip6mr_cache_find_parent(mrt, &mfc->mf6cc_origin.sin6_addr,
+                                   &mfc->mf6cc_mcastgrp.sin6_addr, parent);
+       rcu_read_unlock();
+       if (c) {
                write_lock_bh(&mrt_lock);
                c->mf6c_parent = mfc->mf6cc_parent;
                ip6mr_update_thresholds(mrt, c, ttls);
@@ -1502,13 +1531,17 @@ static int ip6mr_mfc_add(struct net *net, struct mr6_table *mrt,
        if (!mrtsock)
                c->mfc_flags |= MFC_STATIC;
 
-       write_lock_bh(&mrt_lock);
-       list_add(&c->list, &mrt->mfc6_cache_array[line]);
-       write_unlock_bh(&mrt_lock);
+       err = rhltable_insert_key(&mrt->mfc6_hash, &c->cmparg, &c->mnode,
+                                 ip6mr_rht_params);
+       if (err) {
+               pr_err("ip6mr: rhtable insert error %d\n", err);
+               ip6mr_cache_free(c);
+               return err;
+       }
+       list_add_tail_rcu(&c->list, &mrt->mfc6_cache_list);
 
-       /*
-        *      Check to see if we resolved a queued list. If so we
-        *      need to send on the frames and tidy up.
+       /* Check to see if we resolved a queued list. If so we
+        * need to send on the frames and tidy up.
         */
        found = false;
        spin_lock_bh(&mfc_unres_lock);
@@ -1539,13 +1572,11 @@ static int ip6mr_mfc_add(struct net *net, struct mr6_table *mrt,
 
 static void mroute_clean_tables(struct mr6_table *mrt, bool all)
 {
-       int i;
+       struct mfc6_cache *c, *tmp;
        LIST_HEAD(list);
-       struct mfc6_cache *c, *next;
+       int i;
 
-       /*
-        *      Shut down all active vif entries
-        */
+       /* Shut down all active vif entries */
        for (i = 0; i < mrt->maxvif; i++) {
                if (!all && (mrt->vif6_table[i].flags & VIFF_STATIC))
                        continue;
@@ -1553,25 +1584,19 @@ static void mroute_clean_tables(struct mr6_table *mrt, bool all)
        }
        unregister_netdevice_many(&list);
 
-       /*
-        *      Wipe the cache
-        */
-       for (i = 0; i < MFC6_LINES; i++) {
-               list_for_each_entry_safe(c, next, &mrt->mfc6_cache_array[i], list) {
-                       if (!all && (c->mfc_flags & MFC_STATIC))
-                               continue;
-                       write_lock_bh(&mrt_lock);
-                       list_del(&c->list);
-                       write_unlock_bh(&mrt_lock);
-
-                       mr6_netlink_event(mrt, c, RTM_DELROUTE);
-                       ip6mr_cache_free(c);
-               }
+       /* Wipe the cache */
+       list_for_each_entry_safe(c, tmp, &mrt->mfc6_cache_list, list) {
+               if (!all && (c->mfc_flags & MFC_STATIC))
+                       continue;
+               rhltable_remove(&mrt->mfc6_hash, &c->mnode, ip6mr_rht_params);
+               list_del_rcu(&c->list);
+               mr6_netlink_event(mrt, c, RTM_DELROUTE);
+               ip6mr_cache_free(c);
        }
 
        if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {
                spin_lock_bh(&mfc_unres_lock);
-               list_for_each_entry_safe(c, next, &mrt->mfc6_unres_queue, list) {
+               list_for_each_entry_safe(c, tmp, &mrt->mfc6_unres_queue, list) {
                        list_del(&c->list);
                        mr6_netlink_event(mrt, c, RTM_DELROUTE);
                        ip6mr_destroy_unres(mrt, c);
@@ -1905,19 +1930,19 @@ int ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg)
                if (copy_from_user(&sr, arg, sizeof(sr)))
                        return -EFAULT;
 
-               read_lock(&mrt_lock);
+               rcu_read_lock();
                c = ip6mr_cache_find(mrt, &sr.src.sin6_addr, &sr.grp.sin6_addr);
                if (c) {
                        sr.pktcnt = c->mfc_un.res.pkt;
                        sr.bytecnt = c->mfc_un.res.bytes;
                        sr.wrong_if = c->mfc_un.res.wrong_if;
-                       read_unlock(&mrt_lock);
+                       rcu_read_unlock();
 
                        if (copy_to_user(arg, &sr, sizeof(sr)))
                                return -EFAULT;
                        return 0;
                }
-               read_unlock(&mrt_lock);
+               rcu_read_unlock();
                return -EADDRNOTAVAIL;
        default:
                return -ENOIOCTLCMD;
@@ -1979,19 +2004,19 @@ int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
                if (copy_from_user(&sr, arg, sizeof(sr)))
                        return -EFAULT;
 
-               read_lock(&mrt_lock);
+               rcu_read_lock();
                c = ip6mr_cache_find(mrt, &sr.src.sin6_addr, &sr.grp.sin6_addr);
                if (c) {
                        sr.pktcnt = c->mfc_un.res.pkt;
                        sr.bytecnt = c->mfc_un.res.bytes;
                        sr.wrong_if = c->mfc_un.res.wrong_if;
-                       read_unlock(&mrt_lock);
+                       rcu_read_unlock();
 
                        if (copy_to_user(arg, &sr, sizeof(sr)))
                                return -EFAULT;
                        return 0;
                }
-               read_unlock(&mrt_lock);
+               rcu_read_unlock();
                return -EADDRNOTAVAIL;
        default:
                return -ENOIOCTLCMD;
@@ -2115,10 +2140,14 @@ static void ip6_mr_forward(struct net *net, struct mr6_table *mrt,
                /* For an (*,G) entry, we only check that the incoming
                 * interface is part of the static tree.
                 */
+               rcu_read_lock();
                cache_proxy = ip6mr_cache_find_any_parent(mrt, vif);
                if (cache_proxy &&
-                   cache_proxy->mfc_un.res.ttls[true_vifi] < 255)
+                   cache_proxy->mfc_un.res.ttls[true_vifi] < 255) {
+                       rcu_read_unlock();
                        goto forward;
+               }
+               rcu_read_unlock();
        }
 
        /*
@@ -2535,34 +2564,30 @@ static int ip6mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
        struct mr6_table *mrt;
        struct mfc6_cache *mfc;
        unsigned int t = 0, s_t;
-       unsigned int h = 0, s_h;
        unsigned int e = 0, s_e;
 
        s_t = cb->args[0];
-       s_h = cb->args[1];
-       s_e = cb->args[2];
+       s_e = cb->args[1];
 
-       read_lock(&mrt_lock);
+       rcu_read_lock();
        ip6mr_for_each_table(mrt, net) {
                if (t < s_t)
                        goto next_table;
-               if (t > s_t)
-                       s_h = 0;
-               for (h = s_h; h < MFC6_LINES; h++) {
-                       list_for_each_entry(mfc, &mrt->mfc6_cache_array[h], list) {
-                               if (e < s_e)
-                                       goto next_entry;
-                               if (ip6mr_fill_mroute(mrt, skb,
-                                                     NETLINK_CB(cb->skb).portid,
-                                                     cb->nlh->nlmsg_seq,
-                                                     mfc, RTM_NEWROUTE,
-                                                     NLM_F_MULTI) < 0)
-                                       goto done;
+               list_for_each_entry_rcu(mfc, &mrt->mfc6_cache_list, list) {
+                       if (e < s_e)
+                               goto next_entry;
+                       if (ip6mr_fill_mroute(mrt, skb,
+                                             NETLINK_CB(cb->skb).portid,
+                                             cb->nlh->nlmsg_seq,
+                                             mfc, RTM_NEWROUTE,
+                                             NLM_F_MULTI) < 0)
+                               goto done;
 next_entry:
-                               e++;
-                       }
-                       e = s_e = 0;
+                       e++;
                }
+               e = 0;
+               s_e = 0;
+
                spin_lock_bh(&mfc_unres_lock);
                list_for_each_entry(mfc, &mrt->mfc6_unres_queue, list) {
                        if (e < s_e)
@@ -2580,15 +2605,13 @@ next_entry2:
                }
                spin_unlock_bh(&mfc_unres_lock);
                e = s_e = 0;
-               s_h = 0;
 next_table:
                t++;
        }
 done:
-       read_unlock(&mrt_lock);
+       rcu_read_unlock();
 
-       cb->args[2] = e;
-       cb->args[1] = h;
+       cb->args[1] = e;
        cb->args[0] = t;
 
        return skb->len;