fib_trie: Use unsigned long for anything dealing with a shift by bits

This change makes it so that anything that can be shifted by, or compared
to a value shifted by bits is updated to be an unsigned long.  This is
mostly a precaution against an insanely huge address space that somehow
starts coming close to the 2^32 root node size which would require
something like 1.5 billion addresses.

I chose unsigned long instead of unsigned long long since I do not believe
it is possible to allocate a 32 bit tnode on a 32 bit system as the memory
consumed would be 16GB + 28B which exceeds the addressible space for any
one process.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 27 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 9d675486b38c..28a3065470bc 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -146,8 +146,8 @@ struct trie {
 #endif
 };
 
-static void tnode_put_child_reorg(struct tnode *tn, int i, struct tnode *n,
-                                  int wasfull);
+static void tnode_put_child_reorg(struct tnode *tn, unsigned long i,
+                                  struct tnode *n, int wasfull);
 static struct tnode *resize(struct trie *t, struct tnode *tn);
 static struct tnode *inflate(struct trie *t, struct tnode *tn);
 static struct tnode *halve(struct trie *t, struct tnode *tn);
@@ -183,25 +183,23 @@ static inline void node_set_parent(struct tnode *n, struct tnode *tp)
 /* This provides us with the number of children in this node, in the case of a
  * leaf this will return 0 meaning none of the children are accessible.
  */
-static inline int tnode_child_length(const struct tnode *tn)
+static inline unsigned long tnode_child_length(const struct tnode *tn)
 {
         return (1ul << tn->bits) & ~(1ul);
 }
 
-/*
- * caller must hold RTNL
- */
-static inline struct tnode *tnode_get_child(const struct tnode *tn, unsigned int i)
+/* caller must hold RTNL */
+static inline struct tnode *tnode_get_child(const struct tnode *tn,
+                                            unsigned long i)
 {
         BUG_ON(i >= tnode_child_length(tn));
 
         return rtnl_dereference(tn->child[i]);
 }
 
-/*
- * caller must hold RCU read lock or RTNL
- */
-static inline struct tnode *tnode_get_child_rcu(const struct tnode *tn, unsigned int i)
+/* caller must hold RCU read lock or RTNL */
+static inline struct tnode *tnode_get_child_rcu(const struct tnode *tn,
+                                                unsigned long i)
 {
         BUG_ON(i >= tnode_child_length(tn));
 
@@ -400,7 +398,7 @@ static inline int tnode_full(const struct tnode *tn, const struct tnode *n)
         return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
 }
 
-static inline void put_child(struct tnode *tn, int i,
+static inline void put_child(struct tnode *tn, unsigned long i,
                              struct tnode *n)
 {
         tnode_put_child_reorg(tn, i, n, -1);
@@ -411,13 +409,13 @@ static inline void put_child(struct tnode *tn, int i,
   * Update the value of full_children and empty_children.
   */
 
-static void tnode_put_child_reorg(struct tnode *tn, int i, struct tnode *n,
-                                  int wasfull)
+static void tnode_put_child_reorg(struct tnode *tn, unsigned long i,
+                                  struct tnode *n, int wasfull)
 {
         struct tnode *chi = rtnl_dereference(tn->child[i]);
         int isfull;
 
-        BUG_ON(i >= 1<<tn->bits);
+        BUG_ON(i >= tnode_child_length(tn));
 
         /* update emptyChildren */
         if (n == NULL && chi != NULL)
@@ -607,10 +605,10 @@ no_children:
 static void tnode_clean_free(struct tnode *tn)
 {
         struct tnode *tofree;
-        int i;
+        unsigned long i;
 
         for (i = 0; i < tnode_child_length(tn); i++) {
-                tofree = rtnl_dereference(tn->child[i]);
+                tofree = tnode_get_child(tn, i);
                 if (tofree)
                         node_free(tofree);
         }
@@ -619,10 +617,10 @@ static void tnode_clean_free(struct tnode *tn)
 
 static struct tnode *inflate(struct trie *t, struct tnode *oldtnode)
 {
-        int olen = tnode_child_length(oldtnode);
+        unsigned long olen = tnode_child_length(oldtnode);
         struct tnode *tn;
+        unsigned long i;
         t_key m;
-        int i;
 
         pr_debug("In inflate\n");
 
@@ -664,7 +662,7 @@ static struct tnode *inflate(struct trie *t, struct tnode *oldtnode)
         for (i = 0; i < olen; i++) {
                 struct tnode *inode = tnode_get_child(oldtnode, i);
                 struct tnode *left, *right;
-                int size, j;
+                unsigned long size, j;
 
                 /* An empty child */
                 if (inode == NULL)
@@ -737,7 +735,7 @@ nomem:
 
 static struct tnode *halve(struct trie *t, struct tnode *oldtnode)
 {
-        int olen = tnode_child_length(oldtnode);
+        unsigned long olen = tnode_child_length(oldtnode);
         struct tnode *tn, *left, *right;
         int i;
 
@@ -1532,9 +1530,9 @@ static int trie_flush_leaf(struct tnode *l)
 static struct tnode *leaf_walk_rcu(struct tnode *p, struct tnode *c)
 {
         do {
-                t_key idx = c ? idx = get_index(c->key, p) + 1 : 0;
+                unsigned long idx = c ? idx = get_index(c->key, p) + 1 : 0;
 
-                while (idx < 1u << p->bits) {
+                while (idx < tnode_child_length(p)) {
                         c = tnode_get_child_rcu(p, idx++);
                         if (!c)
                                 continue;
@@ -1786,8 +1784,8 @@ struct fib_trie_iter {
 
 static struct tnode *fib_trie_get_next(struct fib_trie_iter *iter)
 {
+        unsigned long cindex = iter->index;
         struct tnode *tn = iter->tnode;
-        unsigned int cindex = iter->index;
         struct tnode *p;
 
         /* A single entry routing table */
@@ -1797,7 +1795,7 @@ static struct tnode *fib_trie_get_next(struct fib_trie_iter *iter)
         pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
                  iter->tnode, iter->index, iter->depth);
 rescan:
-        while (cindex < (1<<tn->bits)) {
+        while (cindex < tnode_child_length(tn)) {
                 struct tnode *n = tnode_get_child_rcu(tn, cindex);
 
                 if (n) {
@@ -1874,15 +1872,16 @@ static void trie_collect_stats(struct trie *t, struct trie_stat *s)
                         hlist_for_each_entry_rcu(li, &n->list, hlist)
                                 ++s->prefixes;
                 } else {
-                        int i;
+                        unsigned long i;
 
                         s->tnodes++;
                         if (n->bits < MAX_STAT_DEPTH)
                                 s->nodesizes[n->bits]++;
 
-                        for (i = 0; i < tnode_child_length(n); i++)
+                        for (i = 0; i < tnode_child_length(n); i++) {
                                 if (!rcu_access_pointer(n->child[i]))
                                         s->nullpointers++;
+                        }
                 }
         }
         rcu_read_unlock();