net_sched: avoid generating same handle for u32 filters

[cascardo/linux.git] / net / sched / cls_u32.c

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index c39b583..70c0be8 100644 (file)
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -38,6 +38,7 @@
 #include <linux/errno.h>
 #include <linux/rtnetlink.h>
 #include <linux/skbuff.h>
+#include <linux/bitmap.h>
 #include <net/netlink.h>
 #include <net/act_api.h>
 #include <net/pkt_cls.h>
@@ -460,17 +461,25 @@ static int u32_delete(struct tcf_proto *tp, unsigned long arg)
        return 0;
 }
 
+#define NR_U32_NODE (1<<12)
 static u32 gen_new_kid(struct tc_u_hnode *ht, u32 handle)
 {
        struct tc_u_knode *n;
-       unsigned int i = 0x7FF;
+       unsigned long i;
+       unsigned long *bitmap = kzalloc(BITS_TO_LONGS(NR_U32_NODE) * sizeof(unsigned long),
+                                       GFP_KERNEL);
+       if (!bitmap)
+               return handle | 0xFFF;
 
        for (n = ht->ht[TC_U32_HASH(handle)]; n; n = n->next)
-               if (i < TC_U32_NODE(n->handle))
-                       i = TC_U32_NODE(n->handle);
-       i++;
+               set_bit(TC_U32_NODE(n->handle), bitmap);
 
-       return handle | (i > 0xFFF ? 0xFFF : i);
+       i = find_next_zero_bit(bitmap, NR_U32_NODE, 0x800);
+       if (i >= NR_U32_NODE)
+               i = find_next_zero_bit(bitmap, NR_U32_NODE, 1);
+
+       kfree(bitmap);
+       return handle | (i >= NR_U32_NODE ? 0xFFF : i);
 }
 
 static const struct nla_policy u32_policy[TCA_U32_MAX + 1] = {