Re: [PATCH v2 net-next 13/14] selftests: drv-net: test AF_XDP zero-copy with an SKB peer

[Jakub Kicinski <kuba@kernel.org>]

On Thu,  8 Oct 2026 13:49:08 +0200 Maciej Fijalkowski wrote:
> +XSK_BIN = (Path(__file__).parent / "../../../net/lib/xskxceiver").resolve()

cfg.test_dir ? Please don't reinvent the wheel

> +XSK_CASES = XSK_BIN.parent / "xsk/test_xsk_case_defs.h"

> +def _hardware_cases():
> +    defs = XSK_CASES.read_text()
> +    entries = re.findall(r"(?m)^XSK_TEST_CASE\((\w+),\s*\w+,\s*([^)]+)\)", defs)
> +    if not entries or len(entries) != defs.count("XSK_TEST_CASE("):
> +        raise KsftFailEx(f"cannot parse {XSK_CASES}")
> +    variants = []
> +    for test_id, (name, hw) in enumerate(entries):
> +        flags = {flag.strip() for flag in hw.split("|")}
> +        if not flags <= {"0", "XSK_HW_RX", "XSK_HW_TX"}:
> +            raise KsftFailEx(f"invalid hardware directions for {name}: {hw}")
> +        variants += [KsftNamedVariant(f"{d}_{name.lower()}", name, d, test_id)
> +                     for d in ("rx", "tx") if f"XSK_HW_{d.upper()}" in flags]
> +    return variants

?? Just list them, don't over optimize for de-duplication
it's obviously all LLM generated now.

> +def _netns_remote(cfg):
> +    return cfg.env.get("REMOTE_TYPE") == "netns"

You shouldn't have to care, please don't break the abstractions

> +def _control_addr(cfg):
> +    """An SSH remote is reached over its management link. A netns remote is
> +    reached only over the tested link, where the XDP programs pass the
> +    control connection to the stack."""
> +    if _netns_remote(cfg):
> +        return cfg.remote_addr_v["4"]
> +    return cfg.remote.name.rpartition("@")[2]

Suspicious? Not sure why you need this. No existing test does
something like this

> +def _root_cmd(command, host=None, sudo=False, **kwargs):
> +    if sudo:
> +        command = "sudo -n " + command
> +    return cmd(command, host=host, **kwargs)

No hacks like this please, all networking tests can assume root

> +def _remote_binary(cfg, local_binary):
> +    binary = cfg.env.get("XSK_REMOTE_BIN")

Why this variable? Just assume the binary in tree is the one we need?

> +    if not binary:
> +        return cfg.remote.deploy(local_binary)
> +    if cfg.env.get("REMOTE_TYPE") != "ssh":
> +        raise KsftSkipEx("XSK_REMOTE_BIN requires the SSH remote backend")
> +    if cfg.env.get("XSK_REMOTE_DEPLOY", "1") == "0":
> +        result = cmd(f"test -x {shlex.quote(binary)}", host=cfg.remote,
> +                     fail=False)
> +        if result.ret:
> +            raise KsftSkipEx(f"remote xskxceiver is not executable: {binary}")
> +        return binary
> +    upload = binary + ".upload"
> +    cmd(["scp", "-q", str(local_binary), f"{cfg.remote.name}:{upload}"],
> +        shell=False)
> +    cmd(f"mv -f {shlex.quote(upload)} {shlex.quote(binary)}",
> +        host=cfg.remote)

Why any of these hacks/complexity? I think you need a better LLM and
point it at the existing tests. Weird stuff going on here :(