[PATCH net v2 0/2] netdevsim: psp: fix issues with stats collection

[Daniel Zahka <daniel.zahka@gmail.com>]

It has come to my attention via a sashiko review of my net-next series
for aes-gcm in netdevsim [1] that there were preexisting issues with
netdevsim's implementation of psp statistics.

API usage issues:
1. not calling u64_stats_init() on the u64_stats_sync object during
   init
2. not serializing usage of the writer side API during stats update

Logical Bugs:
1. We were incrementing rx stats on the sending devices stats
   counters.

Fix the first set of issues by removing the u64_stats_t api entirely,
and keep track of stats with atomics. Fix the second issue by charging
events to the right netdevsim object.

[1]: https://sashiko.dev/#/patchset/20260508-nsim-psp-crypto-v1-0-4b50ed09b794%40gmail.com

  TAP version 13
  1..28
  ok 1 psp.data_basic_send_v0_ip4
  ok 2 psp.data_basic_send_v0_ip6
  ok 3 psp.data_basic_send_v1_ip4
  ok 4 psp.data_basic_send_v1_ip6
  ok 5 psp.data_basic_send_v2_ip4
  ok 6 psp.data_basic_send_v2_ip6
  ok 7 psp.data_basic_send_v3_ip4
  ok 8 psp.data_basic_send_v3_ip6
  ok 9 psp.data_mss_adjust_ip4
  ok 10 psp.data_mss_adjust_ip6
  ok 11 psp.dev_list_devices
  ok 12 psp.dev_get_device
  ok 13 psp.dev_get_device_bad
  ok 14 psp.dev_rotate
  ok 15 psp.dev_rotate_spi
  ok 16 psp.assoc_basic
  ok 17 psp.assoc_bad_dev
  ok 18 psp.assoc_sk_only_conn
  ok 19 psp.assoc_sk_only_mismatch
  ok 20 psp.assoc_sk_only_mismatch_tx
  ok 21 psp.assoc_sk_only_unconn
  ok 22 psp.assoc_version_mismatch
  ok 23 psp.assoc_twice
  ok 24 psp.data_send_bad_key
  ok 25 psp.data_send_disconnect
  ok 26 psp.data_stale_key
  ok 27 psp.removal_device_rx
  ok 28 psp.removal_device_bi
  # Totals: pass:28 fail:0 xfail:0 xpass:0 skip:0 error:0

Dump stats on both devs tx on one should match rx on other:
local dev:
id=5 ifindex=2 stats={'dev-id': 5, 'key-rotations': 0,
'stale-events': 0, 'rx-packets': 1226, 'rx-bytes': 39244,
'rx-auth-fail': 0, 'rx-error': 0, 'rx-bad': 0, 'tx-packets': 1931,
'tx-bytes': 2478908, 'tx-error': 0}

remote dev:
id=3 ifindex=2 stats={'dev-id': 3, 'key-rotations': 0, 'stale-events':
0, 'rx-packets': 1931, 'rx-bytes': 2478908, 'rx-auth-fail': 0,
'rx-error': 0, 'rx-bad': 0, 'tx-packets': 1226, 'tx-bytes': 39244,
'tx-error': 0}

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
---
Changes in v2:
- get rid of u64_stats_t and use atomics instead
- Link to v1: https://lore.kernel.org/r/20260513-fix-psp-stats-v1-0-cdb3174f252f@gmail.com

---
Daniel Zahka (2):
      netdevsim: psp: update rx stats on the peer netdevsim
      netdevsim: psp: use atomic64 for psp stats counters

 drivers/net/netdevsim/netdevsim.h | 10 ++++------
 drivers/net/netdevsim/psp.c       | 27 +++++++++++----------------
 2 files changed, 15 insertions(+), 22 deletions(-)
---
base-commit: 422b5233b607476ac7176bfa2a101b9a103d7653
change-id: 20260512-fix-psp-stats-e96c6d069d01

Best regards,
-- 
Daniel Zahka <daniel.zahka@gmail.com>