net: sched: take rtnl lock in tc_setup_flow_action()

In order to allow using new flow_action infrastructure from unlocked
classifiers, modify tc_setup_flow_action() to accept new 'rtnl_held'
argument. Take rtnl lock before accessing tc_action data. This is necessary
to protect from concurrent action replace.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 20 insertions, 9 deletions

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 612232492f67..a48824bc1489 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -504,7 +504,7 @@ tcf_match_indev(struct sk_buff *skb, int ifindex)
 }
 
 int tc_setup_flow_action(struct flow_action *flow_action,
-                         const struct tcf_exts *exts);
+                         const struct tcf_exts *exts, bool rtnl_held);
 int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type,
                      void *type_data, bool err_stop, bool rtnl_held);
 int tc_setup_cb_add(struct tcf_block *block, struct tcf_proto *tp,
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 3c103cf9fd0d..8751bb8a682f 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -3266,14 +3266,17 @@ int tc_setup_cb_reoffload(struct tcf_block *block, struct tcf_proto *tp,
 EXPORT_SYMBOL(tc_setup_cb_reoffload);
 
 int tc_setup_flow_action(struct flow_action *flow_action,
-                         const struct tcf_exts *exts)
+                         const struct tcf_exts *exts, bool rtnl_held)
 {
         const struct tc_action *act;
-        int i, j, k;
+        int i, j, k, err = 0;
 
         if (!exts)
                 return 0;
 
+        if (!rtnl_held)
+                rtnl_lock();
+
         j = 0;
         tcf_exts_for_each_action(i, act, exts) {
                 struct flow_action_entry *entry;
@@ -3318,6 +3321,7 @@ int tc_setup_flow_action(struct flow_action *flow_action,
                                 entry->vlan.prio = tcf_vlan_push_prio(act);
                                 break;
                         default:
+                                err = -EOPNOTSUPP;
                                 goto err_out;
                         }
                 } else if (is_tcf_tunnel_set(act)) {
@@ -3335,6 +3339,7 @@ int tc_setup_flow_action(struct flow_action *flow_action,
                                         entry->id = FLOW_ACTION_ADD;
                                         break;
                                 default:
+                                        err = -EOPNOTSUPP;
                                         goto err_out;
                                 }
                                 entry->mangle.htype = tcf_pedit_htype(act, k);
@@ -3393,15 +3398,19 @@ int tc_setup_flow_action(struct flow_action *flow_action,
                         entry->id = FLOW_ACTION_PTYPE;
                         entry->ptype = tcf_skbedit_ptype(act);
                 } else {
+                        err = -EOPNOTSUPP;
                         goto err_out;
                 }
 
                 if (!is_tcf_pedit(act))
                         j++;
         }
-        return 0;
+
 err_out:
-        return -EOPNOTSUPP;
+        if (!rtnl_held)
+                rtnl_unlock();
+
+        return err;
 }
 EXPORT_SYMBOL(tc_setup_flow_action);
 
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 5cb694469b51..fb305bd45d93 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -452,7 +452,8 @@ static int fl_hw_replace_filter(struct tcf_proto *tp,
         cls_flower.rule->match.key = &f->mkey;
         cls_flower.classid = f->res.classid;
 
-        err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts);
+        err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts,
+                                   true);
         if (err) {
                 kfree(cls_flower.rule);
                 if (skip_sw)
@@ -1819,7 +1820,8 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb,
                 cls_flower.rule->match.mask = &f->mask->key;
                 cls_flower.rule->match.key = &f->mkey;
 
-                err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts);
+                err = tc_setup_flow_action(&cls_flower.rule->action, &f->exts,
+                                           true);
                 if (err) {
                         kfree(cls_flower.rule);
                         if (tc_skip_sw(f->flags)) {
diff --git a/net/sched/cls_matchall.c b/net/sched/cls_matchall.c
index 911d1ea28bb2..3266f25011cc 100644
--- a/net/sched/cls_matchall.c
+++ b/net/sched/cls_matchall.c
@@ -97,7 +97,7 @@ static int mall_replace_hw_filter(struct tcf_proto *tp,
         cls_mall.command = TC_CLSMATCHALL_REPLACE;
         cls_mall.cookie = cookie;
 
-        err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts);
+        err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts, true);
         if (err) {
                 kfree(cls_mall.rule);
                 mall_destroy_hw_filter(tp, head, cookie, NULL);
@@ -300,7 +300,7 @@ static int mall_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb,
                 TC_CLSMATCHALL_REPLACE : TC_CLSMATCHALL_DESTROY;
         cls_mall.cookie = (unsigned long)head;
 
-        err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts);
+        err = tc_setup_flow_action(&cls_mall.rule->action, &head->exts, true);
         if (err) {
                 kfree(cls_mall.rule);
                 if (add && tc_skip_sw(head->flags)) {