Re: [RFC net-next 2/2] selftests: drv-net: Test queue xsk attribute

[Jakub Kicinski <kuba@kernel.org>]

On Wed, 29 Jan 2025 17:24:25 +0000 Joe Damato wrote:
> Test that queues which are used for AF_XDP have the xsk attribute set.

> diff --git a/tools/testing/selftests/drivers/.gitignore b/tools/testing/selftests/drivers/.gitignore
> index 09e23b5afa96..3c109144f7ff 100644
> --- a/tools/testing/selftests/drivers/.gitignore
> +++ b/tools/testing/selftests/drivers/.gitignore
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  /dma-buf/udmabuf
>  /s390x/uvdevice/test_uvdevice
> +/net/xdp_helper

Let's create our own gitignore, under drivers/net
we'll get conflicts with random trees if we add to the shared one

>  def sys_get_queues(ifname, qtype='rx') -> int:
>      folders = glob.glob(f'/sys/class/net/{ifname}/queues/{qtype}-*')
> @@ -21,6 +24,31 @@ def nl_get_queues(cfg, nl, qtype='rx'):
>          return len([q for q in queues if q['type'] == qtype])
>      return None
>  
> +def check_xdp(cfg, nl, xdp_queue_id=0) -> None:
> +    test_dir = os.path.dirname(os.path.realpath(__file__))
> +    xdp = subprocess.Popen([f"{test_dir}/xdp_helper", f"{cfg.ifindex}", f"{xdp_queue_id}"],
> +                           stdin=subprocess.PIPE, stdout=subprocess.PIPE, bufsize=1,
> +                           text=True)

add:
	defer(xdp.kill)

here, to make sure test cleanup will always try to kill the process,
then you can remove the xdp.kill() at the end

> +    stdout, stderr = xdp.communicate(timeout=10)
> +    rx = tx = False
> +
> +    queues = nl.queue_get({'ifindex': cfg.ifindex}, dump=True)
> +    if queues:

if not queues:
	raise KsftSkipEx("Netlink reports no queues")

That said only reason I can think of for no queues to be reported would
be that the device is down, which is very weird and we could as well
crash. So maybe the check for queues is not necessary ?

> +        for q in queues:
> +            if q['id'] == 0:
> +                if q['type'] == 'rx':
> +                    rx = True
> +                if q['type'] == 'tx':
> +                    tx = True
> +
> +                ksft_eq(q['xsk'], 1)
> +            else:
> +                ksft_eq(q['xsk'], 0)
> +
> +    ksft_eq(rx, True)
> +    ksft_eq(tx, True)
> +    xdp.kill()