[IPV4]: fib_trie stats fix

fib_triestats has been buggy and caused oopses some platforms as
openwrt.  The patch below should cure those problems.
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/fib_trie.c

@@ -50,7 +50,7 @@
  *		Patrick McHardy <kaber@trash.net>
  */
 
-#define VERSION "0.405"
+#define VERSION "0.406"
 
 #include <linux/config.h>
 #include <asm/uaccess.h>
@@ -84,7 +84,7 @@
 #include "fib_lookup.h"
 
 #undef CONFIG_IP_FIB_TRIE_STATS
-#define MAX_CHILDS 16384
+#define MAX_STAT_DEPTH 32
 
 #define KEYLENGTH (8*sizeof(t_key))
 #define MASK_PFX(k, l) (((l)==0)?0:(k >> (KEYLENGTH-l)) << (KEYLENGTH-l))
@@ -154,7 +154,7 @@ struct trie_stat {
 	unsigned int tnodes;
 	unsigned int leaves;
 	unsigned int nullpointers;
-	unsigned int nodesizes[MAX_CHILDS];
+	unsigned int nodesizes[MAX_STAT_DEPTH];
 };
 
 struct trie {
@@ -2080,7 +2080,9 @@ static void trie_collect_stats(struct trie *t, struct trie_stat *s)
 			int i;
 
 			s->tnodes++;
-			s->nodesizes[tn->bits]++;
+			if(tn->bits < MAX_STAT_DEPTH)
+				s->nodesizes[tn->bits]++;
+
 			for (i = 0; i < (1<<tn->bits); i++)
 				if (!tn->child[i])
 					s->nullpointers++;
@@ -2110,8 +2112,8 @@ static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
 	seq_printf(seq, "\tInternal nodes: %d\n\t", stat->tnodes);
 	bytes += sizeof(struct tnode) * stat->tnodes;
 
-	max = MAX_CHILDS-1;
-	while (max >= 0 && stat->nodesizes[max] == 0)
+	max = MAX_STAT_DEPTH;
+	while (max > 0 && stat->nodesizes[max-1] == 0)
 		max--;
 
 	pointers = 0;