[DECNET]: Increase number of possible routing tables to 2^32

Increase the number of possible routing tables to 2^32 by replacing the
fixed sized array of pointers by a hash table and replacing iterations
over all possible table IDs by hash table walking.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 91 insertions, 34 deletions

diff --git a/net/decnet/dn_table.c b/net/decnet/dn_table.c
index eca7c1e10c8..10e87262b6f 100644
--- a/net/decnet/dn_table.c
+++ b/net/decnet/dn_table.c
@@ -75,9 +75,9 @@ for( ; ((f) = *(fp)) != NULL; (fp) = &(f)->fn_next)
 for( ; ((f) = *(fp)) != NULL && dn_key_eq((f)->fn_key, (key)); (fp) = &(f)->fn_next)
 
 #define RT_TABLE_MIN 1
-
+#define DN_FIB_TABLE_HASHSZ 256
+static struct hlist_head dn_fib_table_hash[DN_FIB_TABLE_HASHSZ];
 static DEFINE_RWLOCK(dn_fib_tables_lock);
-struct dn_fib_table *dn_fib_tables[RT_TABLE_MAX + 1];
 
 static kmem_cache_t *dn_hash_kmem __read_mostly;
 static int dn_fib_hash_zombies;
@@ -361,7 +361,7 @@ static __inline__ int dn_hash_dump_bucket(struct sk_buff *skb,
 {
 	int i, s_i;
 
-	s_i = cb->args[3];
+	s_i = cb->args[4];
 	for(i = 0; f; i++, f = f->fn_next) {
 		if (i < s_i)
 			continue;
@@ -374,11 +374,11 @@ static __inline__ int dn_hash_dump_bucket(struct sk_buff *skb,
 				(f->fn_state & DN_S_ZOMBIE) ? 0 : f->fn_type,
 				f->fn_scope, &f->fn_key, dz->dz_order, 
 				f->fn_info, NLM_F_MULTI) < 0) {
-			cb->args[3] = i;
+			cb->args[4] = i;
 			return -1;
 		}
 	}
-	cb->args[3] = i;
+	cb->args[4] = i;
 	return skb->len;
 }
 
@@ -389,20 +389,20 @@ static __inline__ int dn_hash_dump_zone(struct sk_buff *skb,
 {
 	int h, s_h;
 
-	s_h = cb->args[2];
+	s_h = cb->args[3];
 	for(h = 0; h < dz->dz_divisor; h++) {
 		if (h < s_h)
 			continue;
 		if (h > s_h)
-			memset(&cb->args[3], 0, sizeof(cb->args) - 3*sizeof(cb->args[0]));
+			memset(&cb->args[4], 0, sizeof(cb->args) - 4*sizeof(cb->args[0]));
 		if (dz->dz_hash == NULL || dz->dz_hash[h] == NULL)
 			continue;
 		if (dn_hash_dump_bucket(skb, cb, tb, dz, dz->dz_hash[h]) < 0) {
-			cb->args[2] = h;
+			cb->args[3] = h;
 			return -1;
 		}
 	}
-	cb->args[2] = h;
+	cb->args[3] = h;
 	return skb->len;
 }
 
@@ -413,26 +413,63 @@ static int dn_fib_table_dump(struct dn_fib_table *tb, struct sk_buff *skb,
 	struct dn_zone *dz;
 	struct dn_hash *table = (struct dn_hash *)tb->data;
 
-	s_m = cb->args[1];
+	s_m = cb->args[2];
 	read_lock(&dn_fib_tables_lock);
 	for(dz = table->dh_zone_list, m = 0; dz; dz = dz->dz_next, m++) {
 		if (m < s_m)
 			continue;
 		if (m > s_m)
-			memset(&cb->args[2], 0, sizeof(cb->args) - 2*sizeof(cb->args[0]));
+			memset(&cb->args[3], 0, sizeof(cb->args) - 3*sizeof(cb->args[0]));
 
 		if (dn_hash_dump_zone(skb, cb, tb, dz) < 0) {
-			cb->args[1] = m;
+			cb->args[2] = m;
 			read_unlock(&dn_fib_tables_lock);
 			return -1;
 		}
 	}
 	read_unlock(&dn_fib_tables_lock);
-	cb->args[1] = m;
+	cb->args[2] = m;
 
         return skb->len;
 }
 
+int dn_fib_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	unsigned int h, s_h;
+	unsigned int e = 0, s_e;
+	struct dn_fib_table *tb;
+	struct hlist_node *node;
+	int dumped = 0;
+
+	if (NLMSG_PAYLOAD(cb->nlh, 0) >= sizeof(struct rtmsg) &&
+		((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED)
+			return dn_cache_dump(skb, cb);
+
+	s_h = cb->args[0];
+	s_e = cb->args[1];
+
+	for (h = s_h; h < DN_FIB_TABLE_HASHSZ; h++, s_h = 0) {
+		e = 0;
+		hlist_for_each_entry(tb, node, &dn_fib_table_hash[h], hlist) {
+			if (e < s_e)
+				goto next;
+			if (dumped)
+				memset(&cb->args[2], 0, sizeof(cb->args) -
+				                 2 * sizeof(cb->args[0]));
+			if (tb->dump(tb, skb, cb) < 0)
+				goto out;
+			dumped = 1;
+next:
+			e++;
+		}
+	}
+out:
+	cb->args[1] = e;
+	cb->args[0] = h;
+
+	return skb->len;
+}
+
 static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
 {
 	struct dn_hash *table = (struct dn_hash *)tb->data;
@@ -744,6 +781,8 @@ out:
 struct dn_fib_table *dn_fib_get_table(u32 n, int create)
 {
         struct dn_fib_table *t;
+	struct hlist_node *node;
+	unsigned int h;
 
         if (n < RT_TABLE_MIN)
                 return NULL;
@@ -751,8 +790,15 @@ struct dn_fib_table *dn_fib_get_table(u32 n, int create)
         if (n > RT_TABLE_MAX)
                 return NULL;
 
-        if (dn_fib_tables[n]) 
-                return dn_fib_tables[n];
+	h = n & (DN_FIB_TABLE_HASHSZ - 1);
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(t, node, &dn_fib_table_hash[h], hlist) {
+		if (t->n == n) {
+			rcu_read_unlock();
+			return t;
+		}
+	}
+	rcu_read_unlock();
 
         if (!create)
                 return NULL;
@@ -773,33 +819,37 @@ struct dn_fib_table *dn_fib_get_table(u32 n, int create)
         t->flush  = dn_fib_table_flush;
         t->dump = dn_fib_table_dump;
 	memset(t->data, 0, sizeof(struct dn_hash));
-        dn_fib_tables[n] = t;
+	hlist_add_head_rcu(&t->hlist, &dn_fib_table_hash[h]);
 
         return t;
 }
 
-static void dn_fib_del_tree(u32 n)
-{
-	struct dn_fib_table *t;
-
-	write_lock(&dn_fib_tables_lock);
-	t = dn_fib_tables[n];
-	dn_fib_tables[n] = NULL;
-	write_unlock(&dn_fib_tables_lock);
-
-	kfree(t);
-}
-
 struct dn_fib_table *dn_fib_empty_table(void)
 {
         u32 id;
 
         for(id = RT_TABLE_MIN; id <= RT_TABLE_MAX; id++)
-                if (dn_fib_tables[id] == NULL)
+		if (dn_fib_get_table(id, 0) == NULL)
                         return dn_fib_get_table(id, 1);
         return NULL;
 }
 
+void dn_fib_flush(void)
+{
+        int flushed = 0;
+        struct dn_fib_table *tb;
+	struct hlist_node *node;
+	unsigned int h;
+
+	for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
+		hlist_for_each_entry(tb, node, &dn_fib_table_hash[h], hlist)
+	                flushed += tb->flush(tb);
+        }
+
+        if (flushed)
+                dn_rt_cache_flush(-1);
+}
+
 void __init dn_fib_table_init(void)
 {
 	dn_hash_kmem = kmem_cache_create("dn_fib_info_cache",
@@ -810,10 +860,17 @@ void __init dn_fib_table_init(void)
 
 void __exit dn_fib_table_cleanup(void)
 {
-	int i;
-
-	for (i = RT_TABLE_MIN; i <= RT_TABLE_MAX; ++i)
-		dn_fib_del_tree(i);
+	struct dn_fib_table *t;
+	struct hlist_node *node, *next;
+	unsigned int h;
 
-	return;
+	write_lock(&dn_fib_tables_lock);
+	for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
+		hlist_for_each_entry_safe(t, node, next, &dn_fib_table_hash[h],
+		                          hlist) {
+			hlist_del(&t->hlist);
+			kfree(t);
+		}
+	}
+	write_unlock(&dn_fib_tables_lock);
 }