Stephen Hemminger writes:
 > Change inflate/halve to use the ERR_PTR return value method to
 > avoid having to pass error code by reference.

 Thanks. A tested and fixed patch is below. I found two bugs


 > -    if (!tn) {
 > -            *err = -ENOMEM;
 > -            return oldtnode;
 > -    }
 > +    if (!tn)
 > +            return ERR_PTR(-ENOMEM);

 We must return/use oldtnode in case of memory failure also he test was 
 left child inverted.

 Dave IMO it can be appiled.

 Cheers.
                                        --ro


 Signed-off-by: Robert Olsson <[EMAIL PROTECTED]>
 Signed-off-by: Stephen Hemminger <[EMAIL PROTECTED]>
  

--- net-2.6.14/net/ipv4/fib_trie.c.1    2005-08-08 13:41:36.000000000 +0200
+++ net-2.6.14/net/ipv4/fib_trie.c      2005-08-08 14:47:27.000000000 +0200
@@ -167,8 +167,8 @@
 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, int *err);
-static struct tnode *halve(struct trie *t, struct tnode *tn, int *err);
+static struct tnode *inflate(struct trie *t, struct tnode *tn);
+static struct tnode *halve(struct trie *t, struct tnode *tn);
 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);
@@ -457,6 +457,7 @@
 {
        int i;
        int err = 0;
+       struct tnode *old_tn;
 
        if (!tn)
                return NULL;
@@ -559,9 +560,10 @@
               50 * (tn->full_children + tnode_child_length(tn) - 
tn->empty_children) >=
                                inflate_threshold * tnode_child_length(tn))) {
 
-               tn = inflate(t, tn, &err);
-
-               if (err) {
+               old_tn = tn;
+               tn = inflate(t, tn);
+               if (IS_ERR(tn)) {
+                       tn = old_tn;
 #ifdef CONFIG_IP_FIB_TRIE_STATS
                        t->stats.resize_node_skipped++;
 #endif
@@ -581,9 +583,10 @@
               100 * (tnode_child_length(tn) - tn->empty_children) <
               halve_threshold * tnode_child_length(tn)) {
 
-               tn = halve(t, tn, &err);
-
-               if (err) {
+               old_tn = tn;
+               tn = halve(t, tn);
+               if (IS_ERR(tn)) {
+                       tn = old_tn;
 #ifdef CONFIG_IP_FIB_TRIE_STATS
                        t->stats.resize_node_skipped++;
 #endif
@@ -618,7 +621,7 @@
        return (struct node *) tn;
 }
 
-static struct tnode *inflate(struct trie *t, struct tnode *tn, int *err)
+static struct tnode *inflate(struct trie *t, struct tnode *tn)
 {
        struct tnode *inode;
        struct tnode *oldtnode = tn;
@@ -629,10 +632,8 @@
 
        tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits + 1);
 
-       if (!tn) {
-               *err = -ENOMEM;
-               return oldtnode;
-       }
+       if (!tn) 
+               return ERR_PTR(-ENOMEM);
 
        /*
         * Preallocate and store tnodes before the actual work so we
@@ -653,39 +654,22 @@
 
                        left = tnode_new(inode->key&(~m), inode->pos + 1,
                                         inode->bits - 1);
-
-                       if (!left) {
-                               *err = -ENOMEM;
-                               break;
-                       }
+                       if (!left)
+                               goto nomem;
 
                        right = tnode_new(inode->key|m, inode->pos + 1,
                                          inode->bits - 1);
 
-                       if (!right) {
-                               *err = -ENOMEM;
-                               break;
-                       }
+                        if (!right) {
+                               tnode_free(left);
+                               goto nomem;
+                        }
 
                        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);
                struct tnode *left, *right;
@@ -763,9 +747,22 @@
        }
        tnode_free(oldtnode);
        return tn;
+nomem:
+       {
+               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);
+       
+               return ERR_PTR(-ENOMEM);
+       }
 }
 
-static struct tnode *halve(struct trie *t, struct tnode *tn, int *err)
+static struct tnode *halve(struct trie *t, struct tnode *tn)
 {
        struct tnode *oldtnode = tn;
        struct node *left, *right;
@@ -776,10 +773,8 @@
 
        tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits - 1);
 
-       if (!tn) {
-               *err = -ENOMEM;
-               return oldtnode;
-       }
+       if (!tn)
+               return ERR_PTR(-ENOMEM);
 
        /*
         * Preallocate and store tnodes before the actual work so we
@@ -794,29 +789,16 @@
 
                /* 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);
+                       struct tnode *newn;
+  
+                       newn = tnode_new(left->key, tn->pos + tn->bits, 1);
+  
+                       if (!newn) 
+                               goto nomem;
+  
+                       put_child(t, tn, i/2, (struct node *)newn);
                }
-       }
 
-       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) {
@@ -850,6 +832,19 @@
        }
        tnode_free(oldtnode);
        return tn;
+nomem:
+       {
+               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);
+       
+               return ERR_PTR(-ENOMEM);
+       }
 }
 
 static void trie_init(struct trie *t)
-
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