[PATCH net-next v2 6/6] selftests: net: add leased devmem RX and TX netdev unregister tests

[Mina Almasry <almasrymina@google.com>]

Extend nl_netdev.py to cover netdev unregistration while devmem RX and
TX bindings are active on a virtual netkit device leasing an RX queue
from netdevsim:

1. devmem_lease_bind_rx_unregister_check: binds an RX dmabuf to a netkit
   device backed by a leased netdevsim queue and verifies clean teardown
   both when the virtual netkit device is deleted first (unleasing the
   queue while netdevsim remains up) and when the underlying netdevsim
   device is unregistered directly (which uninstalls the physical queue
   memory provider and cascades unregistration to the leasing netkit).
2. devmem_lease_bind_tx_unregister_check: binds a TX dmabuf to a netkit
   device backed by a leased netdevsim queue and verifies clean teardown
   both when the virtual netkit device is deleted first and when the
   underlying netdevsim device is unregistered directly.

Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
---
 tools/testing/selftests/net/nl_netdev.py | 132 ++++++++++++++++++++++-
 1 file changed, 129 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/nl_netdev.py b/tools/testing/selftests/net/nl_netdev.py
index dd0321c0b463a..fa4b5be093257 100755
--- a/tools/testing/selftests/net/nl_netdev.py
+++ b/tools/testing/selftests/net/nl_netdev.py
@@ -12,8 +12,9 @@ import os
 import struct
 from os import system
 from lib.py import ksft_run, ksft_exit, KsftFailEx, KsftSkipEx
-from lib.py import ksft_eq, ksft_ge, ksft_ne, ksft_raises, ksft_busy_wait
-from lib.py import EthtoolFamily, NetdevFamily, NetdevSimDev, NlError, defer, ip
+from lib.py import ksft_eq, ksft_ge, ksft_ne, ksft_not_in, ksft_raises, ksft_busy_wait
+from lib.py import EthtoolFamily, NetdevFamily, NetdevSimDev, Netlink
+from lib.py import NlError, RtnlFamily, cmd, defer, ip
 
 
 def empty_check(nf) -> None:
@@ -483,6 +484,129 @@ def devmem_bind_tx_unregister_check(_nf) -> None:
     nf_priv.close()
 
 
+def _create_netkit_single(rxqueues=2):
+    """Create a single-device netkit interface for queue lease tests."""
+    ifname = f"nk{os.getpid()}"
+    try:
+        with RtnlFamily() as rtnl:
+            rtnl.newlink(
+                {
+                    "ifname": ifname,
+                    "linkinfo": {
+                        "kind": "netkit",
+                        "data": {
+                            "mode": "l2",
+                            "pairing": "single",
+                        },
+                    },
+                    "num-rx-queues": rxqueues,
+                },
+                flags=[Netlink.NLM_F_CREATE, Netlink.NLM_F_EXCL],
+            )
+    except NlError as e:
+        if e.error in (errno.EOPNOTSUPP, errno.ENOENT):
+            raise KsftSkipEx(f"netkit single mode not supported: {e}") from e
+        raise
+    defer(cmd, f"ip link del dev {ifname}", fail=False)
+
+    link = ip(f"-d link show dev {ifname}", json=True)[0]
+    return ifname, link["ifindex"]
+
+
+def devmem_lease_bind_rx_unregister_check(nf) -> None:
+    """Verify leased RX devmem bindings detach cleanly on virt/phys unregister."""
+    for remove_virt_first in (False, True):
+        dmabuf_fd = _create_udmabuf()
+        defer(os.close, dmabuf_fd)
+        nf_priv = NetdevFamily()
+        defer(nf_priv.close)
+        nsimdev = NetdevSimDev(queue_count=2)
+        defer(nsimdev.remove)
+        nsim = nsimdev.nsims[0]
+
+        ip(f"link set dev {nsim.ifname} up")
+        with EthtoolFamily() as ef:
+            ef.rings_set({"header": {"dev-index": nsim.ifindex},
+                          "tcp-data-split": "enabled"})
+
+        nk_ifname, nk_ifindex = _create_netkit_single(rxqueues=2)
+        ip(f"link set dev {nk_ifname} up")
+
+        res = nf.queue_create({
+            "ifindex": nk_ifindex,
+            "type": "rx",
+            "lease": {
+                "ifindex": nsim.ifindex,
+                "queue": {"id": 1, "type": "rx"},
+            },
+        })
+
+        _devmem_bind(nf_priv.bind_rx, {
+            "ifindex": nk_ifindex,
+            "fd": dmabuf_fd,
+            "queues": [{"id": res["id"], "type": "rx"}],
+        })
+        ksft_ge(_dmabuf_attach_count(dmabuf_fd), 1)
+
+        if remove_virt_first:
+            ip(f"link del dev {nk_ifname}")
+            phys_q = nf.queue_get({"ifindex": nsim.ifindex, "id": 1,
+                                   "type": "rx"})
+            ksft_not_in("dmabuf", phys_q)
+            ksft_not_in("lease", phys_q)
+            ksft_ge(_dmabuf_attach_count(dmabuf_fd), 1)
+            nsimdev.remove()
+        else:
+            nsimdev.remove()
+            ksft_ne(cmd(f"ip link show dev {nk_ifname}", fail=False).ret, 0)
+        ksft_eq(_dmabuf_attach_count(dmabuf_fd), 0)
+
+        nf_priv.close()
+
+
+def devmem_lease_bind_tx_unregister_check(nf) -> None:
+    """Verify leased TX devmem bindings detach cleanly on virt/phys unregister."""
+    for remove_virt_first in (False, True):
+        dmabuf_fd = _create_udmabuf()
+        defer(os.close, dmabuf_fd)
+        nf_priv = NetdevFamily()
+        defer(nf_priv.close)
+        nsimdev = NetdevSimDev(queue_count=2)
+        defer(nsimdev.remove)
+        nsim = nsimdev.nsims[0]
+
+        ip(f"link set dev {nsim.ifname} up")
+
+        nk_ifname, nk_ifindex = _create_netkit_single(rxqueues=2)
+        ip(f"link set dev {nk_ifname} up")
+
+        nf.queue_create({
+            "ifindex": nk_ifindex,
+            "type": "rx",
+            "lease": {
+                "ifindex": nsim.ifindex,
+                "queue": {"id": 1, "type": "rx"},
+            },
+        })
+
+        _devmem_bind(nf_priv.bind_tx, {
+            "ifindex": nk_ifindex,
+            "fd": dmabuf_fd,
+        })
+        ksft_ge(_dmabuf_attach_count(dmabuf_fd), 1)
+
+        if remove_virt_first:
+            ip(f"link del dev {nk_ifname}")
+            ksft_ge(_dmabuf_attach_count(dmabuf_fd), 1)
+            nsimdev.remove()
+        else:
+            nsimdev.remove()
+            ksft_ne(cmd(f"ip link show dev {nk_ifname}", fail=False).ret, 0)
+        ksft_eq(_dmabuf_attach_count(dmabuf_fd), 0)
+
+        nf_priv.close()
+
+
 def main() -> None:
     """ Ksft boiler plate main """
     nf = NetdevFamily()
@@ -498,7 +622,9 @@ def main() -> None:
               page_pool_ifindex_leak_check,
               page_pool_stats_ifindex_check,
               devmem_bind_rx_unregister_check,
-              devmem_bind_tx_unregister_check
+              devmem_bind_tx_unregister_check,
+              devmem_lease_bind_rx_unregister_check,
+              devmem_lease_bind_tx_unregister_check
               ],
              args=(nf, ))
     ksft_exit()
-- 
2.56.0.455.g6c5a503b38-goog