[PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb()

[menglong8.dong@gmail.com]

From: Menglong Dong <imagedong@tencent.com>

In order to get the reasons of skb drops, replace sock_queue_rcv_skb()
used in ping_queue_rcv_skb() with sock_queue_rcv_skb_reason().
Meanwhile, use kfree_skb_reason() instead of kfree_skb().

As we can see in ping_rcv(), 'skb' will be freed if '-1' is returned
by ping_queue_rcv_skb(). In order to get the drop reason of 'skb',
make ping_queue_rcv_skb() return the drop reason.

As ping_queue_rcv_skb() is used as 'ping_prot.backlog_rcv()', we can't
change its return type. (Seems ping_prot.backlog_rcv() is not used?)
Therefore, make it return 'drop_reason * -1' to keep the origin logic.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 net/ipv4/ping.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 3ee947557b88..cd4eb211431a 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -936,12 +936,13 @@ EXPORT_SYMBOL_GPL(ping_recvmsg);
 
 int 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;
 }
-- 
2.35.1