[PATCH net-next 3/7] net: dev: add skb drop reasons to __dev_xmit_skb()

[menglong8.dong@gmail.com]

From: Menglong Dong <imagedong@tencent.com>

Add reasons for skb drops to __dev_xmit_skb() by replacing
kfree_skb_list() with kfree_skb_list_reason(). The drop reason of
SKB_DROP_REASON_QDISC_DROP is introduced for qdisc enqueue fails.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 include/linux/skbuff.h     | 4 ++++
 include/trace/events/skb.h | 1 +
 net/core/dev.c             | 5 +++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index e344603aecc4..62f9d15ec6ec 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -398,6 +398,10 @@ enum skb_drop_reason {
 					 * failed (mapbe an eBPF program
 					 * is tricking?)
 					 */
+	SKB_DROP_REASON_QDISC_DROP,	/* dropped by qdisc when packet
+					 * outputting (failed to enqueue to
+					 * current qdisc)
+					 */
 	SKB_DROP_REASON_MAX,
 };
 
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 3cadf13448c6..80fe15d175e3 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -46,6 +46,7 @@
 	EM(SKB_DROP_REASON_NEIGH_QUEUEFULL, NEIGH_QUEUEFULL)	\
 	EM(SKB_DROP_REASON_NEIGH_DEAD, NEIGH_DEAD)		\
 	EM(SKB_DROP_REASON_QDISC_EGRESS, QDISC_EGRESS)		\
+	EM(SKB_DROP_REASON_QDISC_DROP, QDISC_DROP)		\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM
diff --git a/net/core/dev.c b/net/core/dev.c
index 828946d74a19..3280ba2502cd 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3730,7 +3730,8 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 
 no_lock_out:
 		if (unlikely(to_free))
-			kfree_skb_list(to_free);
+			kfree_skb_list_reason(to_free,
+					      SKB_DROP_REASON_QDISC_DROP);
 		return rc;
 	}
 
@@ -3785,7 +3786,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 	}
 	spin_unlock(root_lock);
 	if (unlikely(to_free))
-		kfree_skb_list(to_free);
+		kfree_skb_list_reason(to_free, SKB_DROP_REASON_QDISC_DROP);
 	if (unlikely(contended))
 		spin_unlock(&q->busylock);
 	return rc;
-- 
2.35.1