net_sched: act: Dont increment refcnt on replace

 This is a bug fix. The existing code tries to kill many
 birds with one stone: Handling binding of actions to
 filters, new actions and replacing of action
 attributes. A simple test case to illustrate:

XXXX
 moja@fe1:~$ sudo tc actions add action drop index 12
 moja@fe1:~$ actions get action gact index 12
 action order 1: gact action drop
  random type none pass val 0
  index 12 ref 1 bind 0
 moja@fe1:~$ sudo tc actions replace action ok index 12
 moja@fe1:~$ actions get action gact index 12
 action order 1: gact action drop
  random type none pass val 0
  index 12 ref 2 bind 0
XXXX

The above shows the refcounf being wrongly incremented on replace.
There are more complex scenarios with binding of actions to filters
that i am leaving out that didnt work as well...

Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_csum.c

@@ -77,16 +77,16 @@ static int tcf_csum_init(struct net *n, struct nlattr *nla, struct nlattr *est,
 				     &csum_idx_gen, &csum_hash_info);
 		if (IS_ERR(pc))
 			return PTR_ERR(pc);
-		p = to_tcf_csum(pc);
 		ret = ACT_P_CREATED;
 	} else {
-		p = to_tcf_csum(pc);
-		if (!ovr) {
-			tcf_hash_release(pc, bind, &csum_hash_info);
+		if (bind)/* dont override defaults */
+			return 0;
+		tcf_hash_release(pc, bind, &csum_hash_info);
+		if (!ovr)
 			return -EEXIST;
-		}
 	}
 
+	p = to_tcf_csum(pc);
 	spin_lock_bh(&p->tcf_lock);
 	p->tcf_action = parm->action;
 	p->update_flags = parm->update_flags;

net/sched/act_gact.c

@@ -102,10 +102,11 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 			return PTR_ERR(pc);
 		ret = ACT_P_CREATED;
 	} else {
-		if (!ovr) {
-			tcf_hash_release(pc, bind, &gact_hash_info);
+		if (bind)/* dont override defaults */
+			return 0;
+		tcf_hash_release(pc, bind, &gact_hash_info);
+		if (!ovr)
 			return -EEXIST;
-		}
 	}
 
 	gact = to_gact(pc);

net/sched/act_ipt.c

@@ -141,10 +141,12 @@ static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est,
 			return PTR_ERR(pc);
 		ret = ACT_P_CREATED;
 	} else {
-		if (!ovr) {
-			tcf_ipt_release(to_ipt(pc), bind);
+		if (bind)/* dont override defaults */
+			return 0;
+		tcf_ipt_release(to_ipt(pc), bind);
+
+		if (!ovr)
 			return -EEXIST;
-		}
 	}
 	ipt = to_ipt(pc);
 

net/sched/act_nat.c

@@ -70,15 +70,15 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
 				     &nat_idx_gen, &nat_hash_info);
 		if (IS_ERR(pc))
 			return PTR_ERR(pc);
-		p = to_tcf_nat(pc);
 		ret = ACT_P_CREATED;
 	} else {
-		p = to_tcf_nat(pc);
-		if (!ovr) {
-			tcf_hash_release(pc, bind, &nat_hash_info);
+		if (bind)
+			return 0;
+		tcf_hash_release(pc, bind, &nat_hash_info);
+		if (!ovr)
 			return -EEXIST;
-		}
 	}
+	p = to_tcf_nat(pc);
 
 	spin_lock_bh(&p->tcf_lock);
 	p->old_addr = parm->old_addr;

net/sched/act_pedit.c

@@ -84,10 +84,12 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 		ret = ACT_P_CREATED;
 	} else {
 		p = to_pedit(pc);
-		if (!ovr) {
-			tcf_hash_release(pc, bind, &pedit_hash_info);
+		tcf_hash_release(pc, bind, &pedit_hash_info);
+		if (bind)
+			return 0;
+		if (!ovr)
 			return -EEXIST;
-		}
+
 		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
 			keys = kmalloc(ksize, GFP_KERNEL);
 			if (keys == NULL)

net/sched/act_police.c

@@ -177,10 +177,12 @@ static int tcf_act_police_locate(struct net *net, struct nlattr *nla,
 			if (bind) {
 				police->tcf_bindcnt += 1;
 				police->tcf_refcnt += 1;
+				return 0;
 			}
 			if (ovr)
 				goto override;
-			return ret;
+			/* not replacing */
+			return -EEXIST;
 		}
 	}
 

net/sched/act_simple.c

@@ -142,10 +142,13 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
 		ret = ACT_P_CREATED;
 	} else {
 		d = to_defact(pc);
-		if (!ovr) {
-			tcf_simp_release(d, bind);
+
+		if (bind)
+			return 0;
+		tcf_simp_release(d, bind);
+		if (!ovr)
 			return -EEXIST;
-		}
+
 		reset_policy(d, defdata, parm);
 	}
 

net/sched/act_skbedit.c

@@ -120,10 +120,11 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 		ret = ACT_P_CREATED;
 	} else {
 		d = to_skbedit(pc);
-		if (!ovr) {
-			tcf_hash_release(pc, bind, &skbedit_hash_info);
+		if (bind)
+			return 0;
+		tcf_hash_release(pc, bind, &skbedit_hash_info);
+		if (!ovr)
 			return -EEXIST;
-		}
 	}
 
 	spin_lock_bh(&d->tcf_lock);