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Subject: [PATCH v3 net-next 7/7] net: udp: use kfree_skb_reason() in __udp_queue_rcv_skb()
Date:   Fri, 28 Jan 2022 15:33:19 +0800
Message-Id: <20220128073319.1017084-8-imagedong@tencent.com>
In-Reply-To: <20220128073319.1017084-1-imagedong@tencent.com>
References: <20220128073319.1017084-1-imagedong@tencent.com>
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From: Menglong Dong <imagedong@tencent.com>

Replace kfree_skb() with kfree_skb_reason() in __udp_queue_rcv_skb().
Following new drop reasons are introduced:

SKB_DROP_REASON_SOCKET_RCVBUFF
SKB_DROP_REASON_PROTO_MEM

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 include/linux/skbuff.h     |  5 +++++
 include/trace/events/skb.h |  2 ++
 net/ipv4/udp.c             | 10 +++++++---
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4e55321e2fc2..2390f6e230fb 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -341,6 +341,11 @@ enum skb_drop_reason {
 						  */
 	SKB_DROP_REASON_XFRM_POLICY,	/* xfrm policy check failed */
 	SKB_DROP_REASON_IP_NOPROTO,	/* no support for IP protocol */
+	SKB_DROP_REASON_SOCKET_RCVBUFF,	/* socket receive buff is full */
+	SKB_DROP_REASON_PROTO_MEM,	/* proto memory limition, such as
+					 * udp packet drop out of
+					 * udp_memory_allocated.
+					 */
 	SKB_DROP_REASON_MAX,
 };
 
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 985e481c092d..cfcfd26399f7 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -25,6 +25,8 @@
 	   UNICAST_IN_L2_MULTICAST)				\
 	EM(SKB_DROP_REASON_XFRM_POLICY, XFRM_POLICY)		\
 	EM(SKB_DROP_REASON_IP_NOPROTO, IP_NOPROTO)		\
+	EM(SKB_DROP_REASON_SOCKET_RCVBUFF, SOCKET_RCVBUFF)	\
+	EM(SKB_DROP_REASON_PROTO_MEM, PROTO_MEM)		\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index e295f7f38398..1f756bb0bb1f 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2093,16 +2093,20 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	rc = __udp_enqueue_schedule_skb(sk, skb);
 	if (rc < 0) {
 		int is_udplite = IS_UDPLITE(sk);
+		int drop_reason;
 
 		/* Note that an ENOMEM error is charged twice */
-		if (rc == -ENOMEM)
+		if (rc == -ENOMEM) {
 			UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS,
 					is_udplite);
-		else
+			drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
+		} else {
 			UDP_INC_STATS(sock_net(sk), UDP_MIB_MEMERRORS,
 				      is_udplite);
+			drop_reason = SKB_DROP_REASON_PROTO_MEM;
+		}
 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
-		kfree_skb(skb);
+		kfree_skb_reason(skb, drop_reason);
 		trace_udp_fail_queue_rcv_skb(rc, sk);
 		return -1;
 	}
-- 
2.34.1