selftests: drv-net: rss_ctx: add rss ctx busy testcase

It should be invalid to delete an rss context while it is being
referenced from an ntuple filter. ethtool core should prevent this
from happening. This patch adds a testcase to verify this behavior.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/drivers/net/hw/rss_ctx.py

@@ -6,7 +6,7 @@
 from lib.py import ksft_run, ksft_pr, ksft_exit, ksft_eq, ksft_ne, ksft_ge, ksft_lt
 from lib.py import NetDrvEpEnv
 from lib.py import EthtoolFamily, NetdevFamily
-from lib.py import KsftSkipEx
+from lib.py import KsftSkipEx, KsftFailEx
 from lib.py import rand_port
 from lib.py import ethtool, ip, defer, GenerateTraffic, CmdExitFailure
 
@@ -606,6 +606,33 @@ def test_rss_context_overlap2(cfg):
     test_rss_context_overlap(cfg, True)
 
 
+def test_delete_rss_context_busy(cfg):
+    """
+    Test that deletion returns -EBUSY when an rss context is being used
+    by an ntuple filter.
+    """
+
+    require_ntuple(cfg)
+
+    # create additional rss context
+    ctx_id = ethtool_create(cfg, "-X", "context new")
+    ctx_deleter = defer(ethtool, f"-X {cfg.ifname} context {ctx_id} delete")
+
+    # utilize context from ntuple filter
+    port = rand_port()
+    flow = f"flow-type tcp{cfg.addr_ipver} dst-port {port} context {ctx_id}"
+    ntuple_id = ethtool_create(cfg, "-N", flow)
+    defer(ethtool, f"-N {cfg.ifname} delete {ntuple_id}")
+
+    # attempt to delete in-use context
+    try:
+        ctx_deleter.exec_only()
+        ctx_deleter.cancel()
+        raise KsftFailEx(f"deleted context {ctx_id} used by rule {ntuple_id}")
+    except CmdExitFailure:
+        pass
+
+
 def main() -> None:
     with NetDrvEpEnv(__file__, nsim_test=False) as cfg:
         cfg.ethnl = EthtoolFamily()
@@ -616,7 +643,8 @@ def main() -> None:
                   test_rss_context, test_rss_context4, test_rss_context32,
                   test_rss_context_dump, test_rss_context_queue_reconfigure,
                   test_rss_context_overlap, test_rss_context_overlap2,
-                  test_rss_context_out_of_order, test_rss_context4_create_with_cfg],
+                  test_rss_context_out_of_order, test_rss_context4_create_with_cfg,
+                  test_delete_rss_context_busy],
                  args=(cfg, ))
     ksft_exit()