net_sched: use idr to allocate bpf filter handles

Instead of calling cls_bpf_get() in a loop to find
a unused handle, just switch to idr API to allocate
new handles.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Chris Mi <chrism@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index 36671b0..6c6b21f 100644 (file)
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -17,6 +17,7 @@
 #include <linux/skbuff.h>
 #include <linux/filter.h>
 #include <linux/bpf.h>
+#include <linux/idr.h>
 
 #include <net/rtnetlink.h>
 #include <net/pkt_cls.h>
@@ -32,7 +33,7 @@ MODULE_DESCRIPTION("TC BPF based classifier");
 
 struct cls_bpf_head {
        struct list_head plist;
-       u32 hgen;
+       struct idr handle_idr;
        struct rcu_head rcu;
 };
 
@@ -238,6 +239,7 @@ static int cls_bpf_init(struct tcf_proto *tp)
                return -ENOBUFS;
 
        INIT_LIST_HEAD_RCU(&head->plist);
+       idr_init(&head->handle_idr);
        rcu_assign_pointer(tp->root, head);
 
        return 0;
@@ -264,6 +266,9 @@ static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 
 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 {
+       struct cls_bpf_head *head = rtnl_dereference(tp->root);
+
+       idr_remove_ext(&head->handle_idr, prog->handle);
        cls_bpf_stop_offload(tp, prog);
        list_del_rcu(&prog->link);
        tcf_unbind_filter(tp, &prog->res);
@@ -287,6 +292,7 @@ static void cls_bpf_destroy(struct tcf_proto *tp)
        list_for_each_entry_safe(prog, tmp, &head->plist, link)
                __cls_bpf_delete(tp, prog);
 
+       idr_destroy(&head->handle_idr);
        kfree_rcu(head, rcu);
 }
 
@@ -421,27 +427,6 @@ static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
        return 0;
 }
 
-static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
-                                  struct cls_bpf_head *head)
-{
-       unsigned int i = 0x80000000;
-       u32 handle;
-
-       do {
-               if (++head->hgen == 0x7FFFFFFF)
-                       head->hgen = 1;
-       } while (--i > 0 && cls_bpf_get(tp, head->hgen));
-
-       if (unlikely(i == 0)) {
-               pr_err("Insufficient number of handles\n");
-               handle = 0;
-       } else {
-               handle = head->hgen;
-       }
-
-       return handle;
-}
-
 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
                          struct tcf_proto *tp, unsigned long base,
                          u32 handle, struct nlattr **tca,
@@ -451,6 +436,7 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
        struct cls_bpf_prog *oldprog = *arg;
        struct nlattr *tb[TCA_BPF_MAX + 1];
        struct cls_bpf_prog *prog;
+       unsigned long idr_index;
        int ret;
 
        if (tca[TCA_OPTIONS] == NULL)
@@ -476,21 +462,30 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
                }
        }
 
-       if (handle == 0)
-               prog->handle = cls_bpf_grab_new_handle(tp, head);
-       else
+       if (handle == 0) {
+               ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
+                                   1, 0x7FFFFFFF, GFP_KERNEL);
+               if (ret)
+                       goto errout;
+               prog->handle = idr_index;
+       } else {
+               if (!oldprog) {
+                       ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
+                                           handle, handle + 1, GFP_KERNEL);
+                       if (ret)
+                               goto errout;
+               }
                prog->handle = handle;
-       if (prog->handle == 0) {
-               ret = -EINVAL;
-               goto errout;
        }
 
        ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
        if (ret < 0)
-               goto errout;
+               goto errout_idr;
 
        ret = cls_bpf_offload(tp, prog, oldprog);
        if (ret) {
+               if (!oldprog)
+                       idr_remove_ext(&head->handle_idr, prog->handle);
                __cls_bpf_delete_prog(prog);
                return ret;
        }
@@ -499,6 +494,7 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
                prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 
        if (oldprog) {
+               idr_replace_ext(&head->handle_idr, prog, handle);
                list_replace_rcu(&oldprog->link, &prog->link);
                tcf_unbind_filter(tp, &oldprog->res);
                call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
@@ -509,6 +505,9 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
        *arg = prog;
        return 0;
 
+errout_idr:
+       if (!oldprog)
+               idr_remove_ext(&head->handle_idr, prog->handle);
 errout:
        tcf_exts_destroy(&prog->exts);
        kfree(prog);