[PATCH net-next 14/14] selftests: net: shaper: Cover recursive node cleanup

[Mohsin Bashir <mohsin.bashr@gmail.com>]

From: Mohsin Bashir <hmohsin@meta.com>

Exercise cleanup of nested nodes after deleting their last queue leaf. The
test builds a two-level node hierarchy and checks that removing the queue
also removes both now-empty node shapers.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Mohsin Bashir <hmohsin@meta.com>
---
 tools/testing/selftests/drivers/net/shaper.py | 59 +++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/tools/testing/selftests/drivers/net/shaper.py b/tools/testing/selftests/drivers/net/shaper.py
index 9264aeb74a7a..a53316726f69 100755
--- a/tools/testing/selftests/drivers/net/shaper.py
+++ b/tools/testing/selftests/drivers/net/shaper.py
@@ -374,6 +374,64 @@ def mixed_parent_group_requires_parent(cfg, nl_shaper) -> None:
     shapers = nl_shaper.get({'ifindex': cfg.ifindex}, dump=True)
     ksft_eq(len(shapers), 0)
 
+def recursive_empty_node_cleanup(cfg, nl_shaper) -> None:
+    r"""Deleting the last leaf recursively removes the emptied ancestors.
+
+        netdev             netdev
+          |       del Q0
+         N1       ------>   (N1 and N2 removed too)
+          |
+         N2
+          |
+         Q0
+    """
+    _require_queues(cfg, 1)
+    _require_caps(cfg, nl_shaper, 'node',
+                  ['support-bw-max', 'support-metric-bps', 'support-nesting'],
+                  "device does not support nested node scope shapers")
+    _require_caps(cfg, nl_shaper, 'queue',
+                  ['support-nesting', 'support-weight'],
+                  "device does not support nested queue scope shapers with weight")
+
+    n1_handle = nl_shaper.group({
+                   'ifindex': cfg.ifindex,
+                   'leaves':[{'handle': {'scope': 'queue', 'id': 0},
+                              'weight': 1}],
+                   'handle': {'scope':'node'},
+                   'metric': 'bps',
+                   'bw-max': 10000})
+    n1_id = n1_handle['handle']['id']
+    defer(_delete_shaper, cfg, nl_shaper, {'scope': 'queue', 'id': 0})
+
+    n2_handle = nl_shaper.group({
+                   'ifindex': cfg.ifindex,
+                   'leaves':[{'handle': {'scope': 'queue', 'id': 0},
+                              'weight': 1}],
+                   'handle': {'scope':'node'},
+                   'parent': {'scope': 'node', 'id': n1_id},
+                   'metric': 'bps',
+                   'bw-max': 5000})
+    n2_id = n2_handle['handle']['id']
+
+    shaper_q0 = nl_shaper.get({'ifindex': cfg.ifindex,
+                               'handle': {'scope': 'queue', 'id': 0}})
+    ksft_eq(shaper_q0, {'ifindex': cfg.ifindex,
+                        'parent': {'scope': 'node', 'id': n2_id},
+                        'handle': {'scope': 'queue', 'id': 0},
+                        'weight': 1})
+
+    nl_shaper.delete({'ifindex': cfg.ifindex,
+                      'handle': {'scope': 'queue', 'id': 0}})
+
+    for handle in ({'scope': 'queue', 'id': 0},
+                   {'scope': 'node', 'id': n2_id},
+                   {'scope': 'node', 'id': n1_id}):
+        with ksft_raises(NlError):
+            nl_shaper.get({'ifindex': cfg.ifindex, 'handle': handle})
+
+    shapers = nl_shaper.get({'ifindex': cfg.ifindex}, dump=True)
+    ksft_eq(len(shapers), 0)
+
 def _group_under_netdev(cfg, nl_shaper, bw_max=None):
     r"""Group queues under a netdev-scope node; caller owns node teardown.
 
@@ -1293,6 +1351,7 @@ def main() -> None:
                   set_all_supported_attrs,
                   invalid_set_preserves_state,
                   mixed_parent_group_requires_parent,
+                  recursive_empty_node_cleanup,
                   basic_groups,
                   basic_groups_with_rate,
                   qgroups,
-- 
2.53.0-Meta