xfrm: Revert false event eliding commits.

As reported by Alexey Dobriyan:

--------------------
setkey now takes several seconds to run this simple script
and it spits "recv: Resource temporarily unavailable" messages.

#!/usr/sbin/setkey -f
flush;
spdflush;

add A B ipcomp 44 -m tunnel -C deflate;
add B A ipcomp 45 -m tunnel -C deflate;

spdadd A B any -P in ipsec
        ipcomp/tunnel/192.168.1.2-192.168.1.3/use;
spdadd B A any -P out ipsec
        ipcomp/tunnel/192.168.1.3-192.168.1.2/use;
--------------------

Obviously applications want the events even when the table
is empty.  So we cannot make this behavioral change.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/key/af_key.c

@@ -1751,7 +1751,7 @@ static int pfkey_flush(struct sock *sk, struct sk_buff *skb, struct sadb_msg *hd
 	audit_info.secid = 0;
 	err = xfrm_state_flush(net, proto, &audit_info);
 	if (err)
-		return 0;
+		return err;
 	c.data.proto = proto;
 	c.seq = hdr->sadb_msg_seq;
 	c.pid = hdr->sadb_msg_pid;
@@ -2713,7 +2713,7 @@ static int pfkey_spdflush(struct sock *sk, struct sk_buff *skb, struct sadb_msg
 	audit_info.secid = 0;
 	err = xfrm_policy_flush(net, XFRM_POLICY_TYPE_MAIN, &audit_info);
 	if (err)
-		return 0;
+		return err;
 	c.data.type = XFRM_POLICY_TYPE_MAIN;
 	c.event = XFRM_MSG_FLUSHPOLICY;
 	c.pid = hdr->sadb_msg_pid;

net/xfrm/xfrm_policy.c

@@ -771,8 +771,7 @@ xfrm_policy_flush_secctx_check(struct net *net, u8 type, struct xfrm_audit *audi
 
 int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info)
 {
-	int dir, err = 0, cnt = 0;
-	struct xfrm_policy *dp;
+	int dir, err = 0;
 
 	write_lock_bh(&xfrm_policy_lock);
 
@@ -790,10 +789,8 @@ int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info)
 				     &net->xfrm.policy_inexact[dir], bydst) {
 			if (pol->type != type)
 				continue;
-			dp = __xfrm_policy_unlink(pol, dir);
+			__xfrm_policy_unlink(pol, dir);
 			write_unlock_bh(&xfrm_policy_lock);
-			if (dp)
-				cnt++;
 
 			xfrm_audit_policy_delete(pol, 1, audit_info->loginuid,
 						 audit_info->sessionid,
@@ -812,10 +809,8 @@ int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info)
 					     bydst) {
 				if (pol->type != type)
 					continue;
-				dp = __xfrm_policy_unlink(pol, dir);
+				__xfrm_policy_unlink(pol, dir);
 				write_unlock_bh(&xfrm_policy_lock);
-				if (dp)
-					cnt++;
 
 				xfrm_audit_policy_delete(pol, 1,
 							 audit_info->loginuid,
@@ -829,8 +824,6 @@ int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info)
 		}
 
 	}
-	if (!cnt)
-		err = -ESRCH;
 	atomic_inc(&flow_cache_genid);
 out:
 	write_unlock_bh(&xfrm_policy_lock);

net/xfrm/xfrm_state.c

@@ -603,14 +603,13 @@ xfrm_state_flush_secctx_check(struct net *net, u8 proto, struct xfrm_audit *audi
 
 int xfrm_state_flush(struct net *net, u8 proto, struct xfrm_audit *audit_info)
 {
-	int i, err = 0, cnt = 0;
+	int i, err = 0;
 
 	spin_lock_bh(&xfrm_state_lock);
 	err = xfrm_state_flush_secctx_check(net, proto, audit_info);
 	if (err)
 		goto out;
 
-	err = -ESRCH;
 	for (i = 0; i <= net->xfrm.state_hmask; i++) {
 		struct hlist_node *entry;
 		struct xfrm_state *x;
@@ -627,15 +626,12 @@ int xfrm_state_flush(struct net *net, u8 proto, struct xfrm_audit *audit_info)
 							audit_info->sessionid,
 							audit_info->secid);
 				xfrm_state_put(x);
-				if (!err)
-					cnt++;
 
 				spin_lock_bh(&xfrm_state_lock);
 				goto restart;
 			}
 		}
 	}
-	if (cnt)
 	err = 0;
 
 out:

net/xfrm/xfrm_user.c

@@ -1525,7 +1525,7 @@ static int xfrm_flush_sa(struct sk_buff *skb, struct nlmsghdr *nlh,
 	audit_info.secid = NETLINK_CB(skb).sid;
 	err = xfrm_state_flush(net, p->proto, &audit_info);
 	if (err)
-		return 0;
+		return err;
 	c.data.proto = p->proto;
 	c.event = nlh->nlmsg_type;
 	c.seq = nlh->nlmsg_seq;
@@ -1677,7 +1677,7 @@ static int xfrm_flush_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
 	audit_info.secid = NETLINK_CB(skb).sid;
 	err = xfrm_policy_flush(net, type, &audit_info);
 	if (err)
-		return 0;
+		return err;
 	c.data.type = type;
 	c.event = nlh->nlmsg_type;
 	c.seq = nlh->nlmsg_seq;