netns: ip6mr: dynamically allocate mfc6_cache_array

Preliminary work to make IPv6 multicast forwarding netns-aware.

Dynamically allocates IPv6 multicast forwarding cache, mfc6_cache_array,
and moves it to struct netns_ipv6. 

At the moment, mfc6_cache_array is only referenced in init_net.

Replace 'ARRAY_SIZE(mfc6_cache_array)' with mfc6_cache_array size: MFC6_LINES.

Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 32 insertions, 16 deletions

diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 4ab0cb01a7a5..14c1bbe68a85 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -57,6 +57,7 @@ struct netns_ipv6 {
         struct sock             *igmp_sk;
 #ifdef CONFIG_IPV6_MROUTE
         struct sock             *mroute6_sk;
+        struct mfc6_cache       **mfc6_cache_array;
         struct mif_device       *vif6_table;
         int                     maxvif;
 #endif
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index fab5aba28a20..287e526ba036 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -68,8 +68,6 @@ static int mroute_do_pim;
 #define mroute_do_pim 0
 #endif
 
-static struct mfc6_cache *mfc6_cache_array[MFC6_LINES]; /* Forwarding cache     */
-
 static struct mfc6_cache *mfc_unres_queue;              /* Queue of unresolved entries */
 static atomic_t cache_resolve_queue_len;                /* Size of unresolved   */
 
@@ -109,10 +107,11 @@ static struct mfc6_cache *ipmr_mfc_seq_idx(struct ipmr_mfc_iter *it, loff_t pos)
 {
         struct mfc6_cache *mfc;
 
-        it->cache = mfc6_cache_array;
+        it->cache = init_net.ipv6.mfc6_cache_array;
         read_lock(&mrt_lock);
-        for (it->ct = 0; it->ct < ARRAY_SIZE(mfc6_cache_array); it->ct++)
-                for (mfc = mfc6_cache_array[it->ct]; mfc; mfc = mfc->next)
+        for (it->ct = 0; it->ct < MFC6_LINES; it->ct++)
+                for (mfc = init_net.ipv6.mfc6_cache_array[it->ct];
+                     mfc; mfc = mfc->next)
                         if (pos-- == 0)
                                 return mfc;
         read_unlock(&mrt_lock);
@@ -243,10 +242,10 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
         if (it->cache == &mfc_unres_queue)
                 goto end_of_list;
 
-        BUG_ON(it->cache != mfc6_cache_array);
+        BUG_ON(it->cache != init_net.ipv6.mfc6_cache_array);
 
-        while (++it->ct < ARRAY_SIZE(mfc6_cache_array)) {
-                mfc = mfc6_cache_array[it->ct];
+        while (++it->ct < MFC6_LINES) {
+                mfc = init_net.ipv6.mfc6_cache_array[it->ct];
                 if (mfc)
                         return mfc;
         }
@@ -274,7 +273,7 @@ static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
 
         if (it->cache == &mfc_unres_queue)
                 spin_unlock_bh(&mfc_unres_lock);
-        else if (it->cache == mfc6_cache_array)
+        else if (it->cache == init_net.ipv6.mfc6_cache_array)
                 read_unlock(&mrt_lock);
 }
 
@@ -680,7 +679,7 @@ static struct mfc6_cache *ip6mr_cache_find(struct in6_addr *origin, struct in6_a
         int line = MFC6_HASH(mcastgrp, origin);
         struct mfc6_cache *c;
 
-        for (c = mfc6_cache_array[line]; c; c = c->next) {
+        for (c = init_net.ipv6.mfc6_cache_array[line]; c; c = c->next) {
                 if (ipv6_addr_equal(&c->mf6c_origin, origin) &&
                     ipv6_addr_equal(&c->mf6c_mcastgrp, mcastgrp))
                         break;
@@ -925,7 +924,8 @@ static int ip6mr_mfc_delete(struct mf6cctl *mfc)
 
         line = MFC6_HASH(&mfc->mf6cc_mcastgrp.sin6_addr, &mfc->mf6cc_origin.sin6_addr);
 
-        for (cp = &mfc6_cache_array[line]; (c = *cp) != NULL; cp = &c->next) {
+        for (cp = &init_net.ipv6.mfc6_cache_array[line];
+             (c = *cp) != NULL; cp = &c->next) {
                 if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&
                     ipv6_addr_equal(&c->mf6c_mcastgrp, &mfc->mf6cc_mcastgrp.sin6_addr)) {
                         write_lock_bh(&mrt_lock);
@@ -978,12 +978,26 @@ static int __net_init ip6mr_net_init(struct net *net)
                 err = -ENOMEM;
                 goto fail;
         }
+
+        /* Forwarding cache */
+        net->ipv6.mfc6_cache_array = kcalloc(MFC6_LINES,
+                                             sizeof(struct mfc6_cache *),
+                                             GFP_KERNEL);
+        if (!net->ipv6.mfc6_cache_array) {
+                err = -ENOMEM;
+                goto fail_mfc6_cache;
+        }
+        return 0;
+
+fail_mfc6_cache:
+        kfree(net->ipv6.vif6_table);
 fail:
         return err;
 }
 
 static void __net_exit ip6mr_net_exit(struct net *net)
 {
+        kfree(net->ipv6.mfc6_cache_array);
         kfree(net->ipv6.vif6_table);
 }
 
@@ -1062,7 +1076,8 @@ static int ip6mr_mfc_add(struct mf6cctl *mfc, int mrtsock)
 
         line = MFC6_HASH(&mfc->mf6cc_mcastgrp.sin6_addr, &mfc->mf6cc_origin.sin6_addr);
 
-        for (cp = &mfc6_cache_array[line]; (c = *cp) != NULL; cp = &c->next) {
+        for (cp = &init_net.ipv6.mfc6_cache_array[line];
+             (c = *cp) != NULL; cp = &c->next) {
                 if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&
                     ipv6_addr_equal(&c->mf6c_mcastgrp, &mfc->mf6cc_mcastgrp.sin6_addr))
                         break;
@@ -1093,8 +1108,8 @@ static int ip6mr_mfc_add(struct mf6cctl *mfc, int mrtsock)
                 c->mfc_flags |= MFC_STATIC;
 
         write_lock_bh(&mrt_lock);
-        c->next = mfc6_cache_array[line];
-        mfc6_cache_array[line] = c;
+        c->next = init_net.ipv6.mfc6_cache_array[line];
+        init_net.ipv6.mfc6_cache_array[line] = c;
         write_unlock_bh(&mrt_lock);
 
         /*
@@ -1140,10 +1155,10 @@ static void mroute_clean_tables(struct sock *sk)
         /*
          *      Wipe the cache
          */
-        for (i = 0; i < ARRAY_SIZE(mfc6_cache_array); i++) {
+        for (i = 0; i < MFC6_LINES; i++) {
                 struct mfc6_cache *c, **cp;
 
-                cp = &mfc6_cache_array[i];
+                cp = &init_net.ipv6.mfc6_cache_array[i];
                 while ((c = *cp) != NULL) {
                         if (c->mfc_flags & MFC_STATIC) {
                                 cp = &c->next;