[PATCH net-next v2 3/7] net: dev: add skb drop reasons to __dev_xmit_skb()

From: menglong8 . dong
Date: Fri Mar 04 2022 - 01:02:20 EST


From: Menglong Dong <imagedong@xxxxxxxxxxx>

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@xxxxxxxxxxx>
---
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 9d219e266dc7..a3d65e749ea3 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -395,6 +395,10 @@ enum skb_drop_reason {
*/
SKB_DROP_REASON_NEIGH_DEAD, /* neigh entry is dead */
SKB_DROP_REASON_TC_EGRESS, /* dropped in TC egress HOOK */
+ 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 53755e8191a1..dbf3e2e3c1b4 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_TC_EGRESS, TC_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 353322e72a61..2ba331b5b775 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