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Subject: [PATCH net-next v3 2/3] net: icmp: introduce __ping_queue_rcv_skb() to report drop reasons
Date:   Wed, 16 Mar 2022 14:31:47 +0800
Message-Id: <20220316063148.700769-3-imagedong@tencent.com>
In-Reply-To: <20220316063148.700769-1-imagedong@tencent.com>
References: <20220316063148.700769-1-imagedong@tencent.com>
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From: Menglong Dong <imagedong@tencent.com>

In order to avoid to change the return value of ping_queue_rcv_skb(),
introduce the function __ping_queue_rcv_skb(), which is able to report
the reasons of skb drop as its return value, as Paolo suggested.

Meanwhile, make ping_queue_rcv_skb() a simple call to
__ping_queue_rcv_skb().

The kfree_skb() and sock_queue_rcv_skb() used in ping_queue_rcv_skb()
are replaced with kfree_skb_reason() and sock_queue_rcv_skb_reason()
now.

Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
v3:
- fix aligenment problem

v2:
- introduce __ping_queue_rcv_skb() instead of change the return value
  of ping_queue_rcv_skb()
---
 net/ipv4/ping.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 3ee947557b88..9a1ea6c263f8 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -934,16 +934,24 @@ int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 }
 EXPORT_SYMBOL_GPL(ping_recvmsg);
 
-int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+static enum skb_drop_reason __ping_queue_rcv_skb(struct sock *sk,
+						 struct sk_buff *skb)
 {
+	enum skb_drop_reason reason;
+
 	pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 		 inet_sk(sk), inet_sk(sk)->inet_num, skb);
-	if (sock_queue_rcv_skb(sk, skb) < 0) {
-		kfree_skb(skb);
+	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
+		kfree_skb_reason(skb, reason);
 		pr_debug("ping_queue_rcv_skb -> failed\n");
-		return -1;
+		return reason;
 	}
-	return 0;
+	return SKB_NOT_DROPPED_YET;
+}
+
+int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+	return __ping_queue_rcv_skb(sk, skb) ?: -1;
 }
 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 
-- 
2.35.1