[PATCH net-next v1 4/4] selftests: net: add leased devmem RX and TX netdev unregister tests

[Mina Almasry <almasrymina@google.com>]

Add devmem_lease_bind_rx_unregister_check and
devmem_lease_bind_tx_unregister_check to nl_netdev.py to verify that
leased RX and TX devmem bindings on a netkit interface backed by a
netdevsim queue detach their dma-buf cleanly while the netlink socket
remains open, both when the virtual device (bind_dev) is unregistered
before the physical device (map_dev) and when the physical device is
unregistered directly (which uninstalls the physical queue memory
provider and cascades unregistration to the leasing netkit).

Signed-off-by: Mina Almasry <almasrymina@google.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()
-- 
2.56.0.385.gac671c819a-goog