[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 eca7c1e10c80..10e87262b6fb 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);
 }