[PATCH net] Revert "fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied"

[Hangbin Liu <liuhangbin@gmail.com>]

This reverts commit e9919a24d3022f72bcadc407e73a6ef17093a849.

Nathan reported the new behaviour breaks Android, as Android just add
new rules and delete old ones.

If we return 0 without adding dup rules, Android will remove the new
added rules and causing system to soft-reboot.

Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Fixes: e9919a24d302 ("fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 net/core/fib_rules.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 43f0115cce9c..18f8dd8329ed 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -757,9 +757,9 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err)
 		goto errout;
 
-	if (rule_exists(ops, frh, tb, rule)) {
-		if (nlh->nlmsg_flags & NLM_F_EXCL)
-			err = -EEXIST;
+	if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
+	    rule_exists(ops, frh, tb, rule)) {
+		err = -EEXIST;
 		goto errout_free;
 	}
 
-- 
2.19.2