[PATCH v2 net-next 0/3] net: skb: introduce kfree_skb_with_reason() and use it for tcp and udp

[menglong8.dong@gmail.com]

From: Menglong Dong <imagedong@tencent.com>

In this series patch, the interface kfree_skb_with_reason() is
introduced(), which is used to collect skb drop reason, and pass
it to 'kfree_skb' tracepoint. Therefor, 'drop_monitor' or eBPF is
able to monitor abnormal skb with detail reason.

In fact, this series patches are out of the intelligence of David
and Steve, I'm just a truck man :/

Previous discussion is here:

https://lore.kernel.org/netdev/20211118105752.1d46e990@gandalf.local.home/
https://lore.kernel.org/netdev/67b36bd8-2477-88ac-83a0-35a1eeaf40c9@gmail.com/

In the first patch, kfree_skb_with_reason() is introduced and
the 'reason' field is added to 'kfree_skb' tracepoint. In the
second patch, 'kfree_skb()' in replaced with 'kfree_skb_with_reason()'
in tcp_v4_rcv(). In the third patch, 'kfree_skb_with_reason()' is
used in __udp4_lib_rcv().

Changes since v1:
- rename some drop reason, as David suggested
- add the third patch


Menglong Dong (3):
  net: skb: introduce kfree_skb_with_reason()
  net: skb: use kfree_skb_with_reason() in tcp_v4_rcv()
  net: skb: use kfree_skb_with_reason() in __udp4_lib_rcv()

 include/linux/skbuff.h     | 18 +++++++++++++++++
 include/trace/events/skb.h | 41 +++++++++++++++++++++++++++++++-------
 net/core/dev.c             |  3 ++-
 net/core/drop_monitor.c    | 10 +++++++---
 net/core/skbuff.c          | 22 +++++++++++++++++++-
 net/ipv4/tcp_ipv4.c        | 14 ++++++++++---
 net/ipv4/udp.c             | 10 ++++++++--
 7 files changed, 101 insertions(+), 17 deletions(-)

-- 
2.27.0