netfilter: nat: Do not use ARRAY_SIZE() on spinlocks to fix zero div

If no spinlock debugging options (CONFIG_GENERIC_LOCKBREAK,
CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_LOCK_ALLOC) are enabled on a UP
platform (e.g. m68k defconfig), arch_spinlock_t is an empty struct,
hence using ARRAY_SIZE(nf_nat_locks) causes a division by zero:

    net/netfilter/nf_nat_core.c: In function ‘nf_nat_setup_info’:
    net/netfilter/nf_nat_core.c:432: warning: division by zero
    net/netfilter/nf_nat_core.c: In function ‘__nf_nat_cleanup_conntrack’:
    net/netfilter/nf_nat_core.c:535: warning: division by zero
    net/netfilter/nf_nat_core.c:537: warning: division by zero
    net/netfilter/nf_nat_core.c: In function ‘nf_nat_init’:
    net/netfilter/nf_nat_core.c:810: warning: division by zero
    net/netfilter/nf_nat_core.c:811: warning: division by zero
    net/netfilter/nf_nat_core.c:824: warning: division by zero

Fix this by using the CONNTRACK_LOCKS definition instead.

Suggested-by: Florian Westphal <fw@strlen.de>
Fixes: 8073e960a03bf7b5 ("netfilter: nat: use keyed locks")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index f393a70..af8345f 100644 (file)
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -429,7 +429,7 @@ nf_nat_setup_info(struct nf_conn *ct,
 
                srchash = hash_by_src(net,
                                      &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
-               lock = &nf_nat_locks[srchash % ARRAY_SIZE(nf_nat_locks)];
+               lock = &nf_nat_locks[srchash % CONNTRACK_LOCKS];
                spin_lock_bh(lock);
                hlist_add_head_rcu(&ct->nat_bysource,
                                   &nf_nat_bysource[srchash]);
@@ -532,9 +532,9 @@ static void __nf_nat_cleanup_conntrack(struct nf_conn *ct)
        unsigned int h;
 
        h = hash_by_src(nf_ct_net(ct), &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
-       spin_lock_bh(&nf_nat_locks[h % ARRAY_SIZE(nf_nat_locks)]);
+       spin_lock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
        hlist_del_rcu(&ct->nat_bysource);
-       spin_unlock_bh(&nf_nat_locks[h % ARRAY_SIZE(nf_nat_locks)]);
+       spin_unlock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
 }
 
 static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
@@ -807,8 +807,8 @@ static int __init nf_nat_init(void)
 
        /* Leave them the same for the moment. */
        nf_nat_htable_size = nf_conntrack_htable_size;
-       if (nf_nat_htable_size < ARRAY_SIZE(nf_nat_locks))
-               nf_nat_htable_size = ARRAY_SIZE(nf_nat_locks);
+       if (nf_nat_htable_size < CONNTRACK_LOCKS)
+               nf_nat_htable_size = CONNTRACK_LOCKS;
 
        nf_nat_bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size, 0);
        if (!nf_nat_bysource)
@@ -821,7 +821,7 @@ static int __init nf_nat_init(void)
                return ret;
        }
 
-       for (i = 0; i < ARRAY_SIZE(nf_nat_locks); i++)
+       for (i = 0; i < CONNTRACK_LOCKS; i++)
                spin_lock_init(&nf_nat_locks[i]);
 
        nf_ct_helper_expectfn_register(&follow_master_nat);