cls_u32: Reinstate cyclic allocation

Commit e7614370d6f0 ("net_sched: use idr to allocate u32 filter handles)
converted htid allocation to use the IDR.  The ID allocated by this
scheme changes; it used to be cyclic, but now always allocates the
lowest available.  The IDR supports cyclic allocation, so just use
the right function.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 5b256da985b15e492e9f3c30b57674c5bb7287d5..d2805f24ddd37eff0c3bedde5695d52bca4a8bc7 100644 (file)
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -316,19 +316,13 @@ static void *u32_get(struct tcf_proto *tp, u32 handle)
        return u32_lookup_key(ht, handle);
 }
 
+/* Protected by rtnl lock */
 static u32 gen_new_htid(struct tc_u_common *tp_c, struct tc_u_hnode *ptr)
 {
-       unsigned long idr_index;
-       int err;
-
-       /* This is only used inside rtnl lock it is safe to increment
-        * without read _copy_ update semantics
-        */
-       err = idr_alloc_ext(&tp_c->handle_idr, ptr, &idr_index,
-                           1, 0x7FF, GFP_KERNEL);
-       if (err)
+       int id = idr_alloc_cyclic(&tp_c->handle_idr, ptr, 1, 0x7FF, GFP_KERNEL);
+       if (id < 0)
                return 0;
-       return (u32)(idr_index | 0x800) << 20;
+       return (id | 0x800U) << 20;
 }
 
 static struct hlist_head *tc_u_common_hash;