1 files changed, 145 insertions, 32 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 9038b914b4b1..4be234c7d8c3 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -43,7 +43,7 @@
  *              2 of the License, or (at your option) any later version.
  */
 
-#define VERSION "0.324"
+#define VERSION "0.325"
 
 #include <linux/config.h>
 #include <asm/uaccess.h>
@@ -136,6 +136,7 @@ struct trie_use_stats {
         unsigned int semantic_match_passed;
         unsigned int semantic_match_miss;
         unsigned int null_node_hit;
+        unsigned int resize_node_skipped;
 };
 #endif
 
@@ -164,8 +165,8 @@ static void put_child(struct trie *t, struct tnode *tn, int i, struct node *n);
 static void tnode_put_child_reorg(struct tnode *tn, int i, struct node *n, int wasfull);
 static int tnode_child_length(struct tnode *tn);
 static struct node *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);
+static struct tnode *inflate(struct trie *t, struct tnode *tn, int *err);
+static struct tnode *halve(struct trie *t, struct tnode *tn, int *err);
 static void tnode_free(struct tnode *tn);
 static void trie_dump_seq(struct seq_file *seq, struct trie *t);
 extern struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio);
@@ -481,6 +482,7 @@ static void tnode_put_child_reorg(struct tnode *tn, int i, struct node *n, int w
 static struct node *resize(struct trie *t, struct tnode *tn) 
 {
         int i;
+        int err = 0;
 
         if (!tn)
                 return NULL;
@@ -577,12 +579,20 @@ static struct node *resize(struct trie *t, struct tnode *tn)
          */
 
         check_tnode(tn);
-
+        
+        err = 0;
         while ((tn->full_children > 0 &&
                50 * (tn->full_children + tnode_child_length(tn) - tn->empty_children) >=
                                 inflate_threshold * tnode_child_length(tn))) {
 
-                tn = inflate(t, tn);
+                tn = inflate(t, tn, &err);
+
+                if(err) {
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+                        t->stats.resize_node_skipped++;
+#endif
+                        break;
+                }
         }
 
         check_tnode(tn);
@@ -591,11 +601,22 @@ static struct node *resize(struct trie *t, struct tnode *tn)
          * Halve as long as the number of empty children in this
          * node is above threshold.
          */
+
+        err = 0;
         while (tn->bits > 1 &&
                100 * (tnode_child_length(tn) - tn->empty_children) <
-               halve_threshold * tnode_child_length(tn))
+               halve_threshold * tnode_child_length(tn)) {
+
+                tn = halve(t, tn, &err);
+
+                if(err) {
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+                        t->stats.resize_node_skipped++;
+#endif
+                        break;
+                }
+        }
 
-                tn = halve(t, tn);
   
         /* Only one child remains */
 
@@ -620,7 +641,7 @@ static struct node *resize(struct trie *t, struct tnode *tn)
         return (struct node *) tn;
 }
 
-static struct tnode *inflate(struct trie *t, struct tnode *tn)
+static struct tnode *inflate(struct trie *t, struct tnode *tn, int *err)
 {
         struct tnode *inode;
         struct tnode *oldtnode = tn;
@@ -632,8 +653,63 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn)
 
         tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits + 1);
 
-        if (!tn)
-                trie_bug("tnode_new failed");
+        if (!tn) {
+                *err = -ENOMEM;
+                return oldtnode;
+        }
+
+        /*
+         * Preallocate and store tnodes before the actual work so we 
+         * don't get into an inconsistent state if memory allocation 
+         * fails. In case of failure we return the oldnode and  inflate 
+         * of tnode is ignored.
+         */
+                        
+        for(i = 0; i < olen; i++) {
+                struct tnode *inode = (struct tnode *) tnode_get_child(oldtnode, i);
+
+                if (inode &&
+                    IS_TNODE(inode) &&
+                    inode->pos == oldtnode->pos + oldtnode->bits &&
+                    inode->bits > 1) {
+                        struct tnode *left, *right;
+
+                        t_key m = TKEY_GET_MASK(inode->pos, 1);
+ 
+                        left = tnode_new(inode->key&(~m), inode->pos + 1,
+                                         inode->bits - 1);
+
+                        if(!left) {
+                                *err = -ENOMEM; 
+                                break;
+                        }
+                        
+                        right = tnode_new(inode->key|m, inode->pos + 1,
+                                          inode->bits - 1);
+
+                        if(!right) {
+                                *err = -ENOMEM; 
+                                break;
+                        }
+
+                        put_child(t, tn, 2*i, (struct node *) left);
+                        put_child(t, tn, 2*i+1, (struct node *) right);
+                }
+        }
+
+        if(*err) {
+                int size = tnode_child_length(tn);
+                int j;
+
+                for(j = 0; j < size; j++) 
+                        if( tn->child[j])
+                                tnode_free((struct tnode *)tn->child[j]);
+
+                tnode_free(tn);
+                
+                *err = -ENOMEM;
+                return oldtnode;
+        }
 
         for(i = 0; i < olen; i++) {
                 struct node *node = tnode_get_child(oldtnode, i);
@@ -646,7 +722,7 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn)
 
                 if(IS_LEAF(node) || ((struct tnode *) node)->pos >
                    tn->pos + tn->bits - 1) {
-                        if(tkey_extract_bits(node->key, tn->pos + tn->bits - 1,
+                        if(tkey_extract_bits(node->key, oldtnode->pos + oldtnode->bits,
                                              1) == 0)
                                 put_child(t, tn, 2*i, node);
                         else
@@ -686,27 +762,22 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn)
                          * the position (inode->pos)
                          */
 
-                        t_key m = TKEY_GET_MASK(inode->pos, 1);
- 
                         /* Use the old key, but set the new significant 
                          *   bit to zero. 
                          */
-                        left = tnode_new(inode->key&(~m), inode->pos + 1,
-                                         inode->bits - 1);
 
-                        if(!left) 
-                                trie_bug("tnode_new failed");
-                        
-                        
-                        /* Use the old key, but set the new significant 
-                         * bit to one. 
-                         */
-                        right = tnode_new(inode->key|m, inode->pos + 1,
-                                          inode->bits - 1);
+                        left = (struct tnode *) tnode_get_child(tn, 2*i);
+                        put_child(t, tn, 2*i, NULL);
+
+                        if(!left)
+                                BUG();
+
+                        right = (struct tnode *) tnode_get_child(tn, 2*i+1);
+                        put_child(t, tn, 2*i+1, NULL);
+
+                        if(!right)
+                                BUG();
 
-                        if(!right) 
-                                trie_bug("tnode_new failed");
-                        
                         size = tnode_child_length(left);
                         for(j = 0; j < size; j++) {
                                 put_child(t, left, j, inode->child[j]);
@@ -722,7 +793,7 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn)
         return tn;
 }
 
-static struct tnode *halve(struct trie *t, struct tnode *tn)
+static struct tnode *halve(struct trie *t, struct tnode *tn, int *err)
 {
         struct tnode *oldtnode = tn;
         struct node *left, *right;
@@ -733,8 +804,48 @@ static struct tnode *halve(struct trie *t, struct tnode *tn)
   
         tn=tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits - 1);
 
-        if(!tn) 
-                trie_bug("tnode_new failed");
+        if (!tn) {
+                *err = -ENOMEM;
+                return oldtnode;
+        }
+
+        /*
+         * Preallocate and store tnodes before the actual work so we 
+         * don't get into an inconsistent state if memory allocation 
+         * fails. In case of failure we return the oldnode and halve 
+         * of tnode is ignored.
+         */
+
+        for(i = 0; i < olen; i += 2) {
+                left = tnode_get_child(oldtnode, i);
+                right = tnode_get_child(oldtnode, i+1);
+    
+                /* Two nonempty children */
+                if( left && right)  {
+                        struct tnode *newBinNode =
+                                tnode_new(left->key, tn->pos + tn->bits, 1);
+
+                        if(!newBinNode) {
+                                *err = -ENOMEM; 
+                                break;
+                        }
+                        put_child(t, tn, i/2, (struct node *)newBinNode);
+                }
+        }
+
+        if(*err) {
+                int size = tnode_child_length(tn);
+                int j;
+
+                for(j = 0; j < size; j++) 
+                        if( tn->child[j])
+                                tnode_free((struct tnode *)tn->child[j]);
+
+                tnode_free(tn);
+                
+                *err = -ENOMEM;
+                return oldtnode;
+        }
 
         for(i = 0; i < olen; i += 2) {
                 left = tnode_get_child(oldtnode, i);
@@ -751,10 +862,11 @@ static struct tnode *halve(struct trie *t, struct tnode *tn)
                 /* Two nonempty children */
                 else {
                         struct tnode *newBinNode =
-                                tnode_new(left->key, tn->pos + tn->bits, 1);
+                                (struct tnode *) tnode_get_child(tn, i/2);
+                        put_child(t, tn, i/2, NULL);
 
                         if(!newBinNode) 
-                                trie_bug("tnode_new failed");
+                                BUG();
 
                         put_child(t, newBinNode, 0, left);
                         put_child(t, newBinNode, 1, right);
@@ -2322,6 +2434,7 @@ static void collect_and_show(struct trie *t, struct seq_file *seq)
         seq_printf(seq,"semantic match passed = %d\n", t->stats.semantic_match_passed);
         seq_printf(seq,"semantic match miss = %d\n", t->stats.semantic_match_miss);
         seq_printf(seq,"null node hit= %d\n", t->stats.null_node_hit);
+        seq_printf(seq,"skipped node resize = %d\n", t->stats.resize_node_skipped);
 #ifdef CLEAR_STATS
         memset(&(t->stats), 0, sizeof(t->stats));
 #endif