net: dev: use kfree_skb_reason() for __netif_receive_skb_core()

Add reason for skb drops to __netif_receive_skb_core() when packet_type
not found to handle the skb. For this purpose, the drop reason
SKB_DROP_REASON_PTYPE_ABSENT is introduced. Take ether packets for
example, this case mainly happens when L3 protocol is not supported.

Signed-off-by: Menglong Dong <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: menglongdong

include/linux/skbuff.h

@@ -407,6 +407,11 @@ enum skb_drop_reason {
 					 */
 	SKB_DROP_REASON_XDP,		/* dropped by XDP in input path */
 	SKB_DROP_REASON_TC_INGRESS,	/* dropped in TC ingress HOOK */
+	SKB_DROP_REASON_PTYPE_ABSENT,	/* not packet_type found to handle
+					 * the skb. For an etner packet,
+					 * this means that L3 protocol is
+					 * not supported
+					 */
 	SKB_DROP_REASON_MAX,
 };
 

include/trace/events/skb.h

@@ -50,6 +50,7 @@
 	EM(SKB_DROP_REASON_CPU_BACKLOG, CPU_BACKLOG)		\
 	EM(SKB_DROP_REASON_XDP, XDP)				\
 	EM(SKB_DROP_REASON_TC_INGRESS, TC_INGRESS)		\
+	EM(SKB_DROP_REASON_PTYPE_ABSENT, PTYPE_ABSENT)		\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM

net/core/dev.c

@@ -5358,11 +5358,13 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
 		*ppt_prev = pt_prev;
 	} else {
 drop:
-		if (!deliver_exact)
+		if (!deliver_exact) {
 			atomic_long_inc(&skb->dev->rx_dropped);
-		else
+			kfree_skb_reason(skb, SKB_DROP_REASON_PTYPE_ABSENT);
+		} else {
 			atomic_long_inc(&skb->dev->rx_nohandler);
-		kfree_skb(skb);
+			kfree_skb(skb);
+		}
 		/* Jamal, now you will not able to escape explaining
 		 * me how you were going to use this. :-)
 		 */