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From:   xu.xin.sc@gmail.com
To:     davem@davemloft.net
Cc:     dsahern@kernel.org, kuba@kernel.org, pabeni@redhat.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        xu xin <xu.xin16@zte.com.cn>,
        Yang Yang <yang.yang29@zte.com.cn>, Si Hao <si.hao@zte.com.cn>
Subject: [PATCH linux-next v2] net/ipv4: return the real errno instead of -EINVAL
Date:   Mon,  7 Aug 2023 01:54:08 +0000
Message-Id: <20230807015408.248237-1-xu.xin16@zte.com.cn>
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From: xu xin <xu.xin16@zte.com.cn>

For now, No matter what error pointer ip_neigh_for_gw() returns,
ip_finish_output2() always return -EINVAL, which may mislead the upper
users.

For exemple, an application uses sendto to send an UDP packet, but when the
neighbor table overflows, sendto() will get a value of -EINVAL, and it will
cause users to waste a lot of time checking parameters for errors.

Return the real errno instead of -EINVAL.

Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Si Hao <si.hao@zte.com.cn>
---
 net/ipv4/ip_output.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 6ba1a0fafbaa..f28c87533a46 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -236,7 +236,7 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s
 	net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
 			    __func__);
 	kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
-	return -EINVAL;
+	return PTR_ERR(neigh);
 }
 
 static int ip_finish_output_gso(struct net *net, struct sock *sk,
-- 
2.15.2