Re: [PATCH net-next v2 4/4] selftests: drv-net: Test that NAPI ID is non-zero

[Joe Damato <jdamato@fastly.com>]

On Thu, Apr 17, 2025 at 06:46:15AM -0700, Jakub Kicinski wrote:
> On Thu, 17 Apr 2025 01:32:42 +0000 Joe Damato wrote:
> > Test that the SO_INCOMING_NAPI_ID of a network file descriptor is
> > non-zero. This ensures that either the core networking stack or, in some
> > cases like netdevsim, the driver correctly sets the NAPI ID.
> > 
> > Signed-off-by: Joe Damato <jdamato@fastly.com>
> > ---
> >  .../testing/selftests/drivers/net/.gitignore  |  1 +
> >  tools/testing/selftests/drivers/net/Makefile  |  6 +-
> >  .../testing/selftests/drivers/net/napi_id.py  | 24 ++++++
> >  .../selftests/drivers/net/napi_id_helper.c    | 83 +++++++++++++++++++
> >  4 files changed, 113 insertions(+), 1 deletion(-)
> >  create mode 100755 tools/testing/selftests/drivers/net/napi_id.py
> >  create mode 100644 tools/testing/selftests/drivers/net/napi_id_helper.c
> > 
> > diff --git a/tools/testing/selftests/drivers/net/.gitignore b/tools/testing/selftests/drivers/net/.gitignore
> > index ec746f374e85..71bd7d651233 100644
> > --- a/tools/testing/selftests/drivers/net/.gitignore
> > +++ b/tools/testing/selftests/drivers/net/.gitignore
> > @@ -1,2 +1,3 @@
> >  # SPDX-License-Identifier: GPL-2.0-only
> >  xdp_helper
> > +napi_id_helper
> 
> sort alphabetically, pls

Thanks, fixed.

> > diff --git a/tools/testing/selftests/drivers/net/napi_id.py b/tools/testing/selftests/drivers/net/napi_id.py
> > new file mode 100755
> > index 000000000000..aee6f90be49b
> > --- /dev/null
> > +++ b/tools/testing/selftests/drivers/net/napi_id.py
> > @@ -0,0 +1,24 @@
> > +#!/usr/bin/env python3
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +from lib.py import ksft_run, ksft_exit
> > +from lib.py import ksft_eq, NetDrvEpEnv
> > +from lib.py import bkg, cmd, rand_port, NetNSEnter
> > +
> > +def test_napi_id(cfg) -> None:
> > +    port = rand_port()
> > +    listen_cmd = f'{cfg.test_dir / "napi_id_helper"} {cfg.addr_v['4']} {port}'
> 
> you need to deploy, in case test is running with a real remote machine
> and the binary has to be copied over:
> 
> 	bin_remote = cfg.remote.deploy(cfg.test_dir / "napi_id_helper")
> 	listen_cmd = f'{bin_remote} {cfg.addr_v['4']} {port}' 

Thanks, fixed.

> > +    with bkg(listen_cmd, ksft_wait=3) as server:
> > +        with NetNSEnter('net', '/proc/self/ns/'):
> > +          cmd(f"echo a | socat - TCP:{cfg.addr_v['4']}:{port}", host=cfg.remote, shell=True)
> 
> Like Xiao Liang said, just host=cfg.remote should work.

You are both correct; sorry about the noise. I thought I tried this
last night and it was failing, but clearly I was wrong/something
else was broken.

I've fixed this locally and dropped patch 3 which is now
unnecessary.

I think the main outstanding thing is Paolo's feedback which maybe
(?) is due to a Python version difference? If you have any guidance
on how to proceed on that, I'd appreciate it [1].

My guess is that I could rewrite that line to concat the strings
instead of interpolate and it would work both on Paolo's system and
mine. Would that be the right way to go?

[1]: https://lore.kernel.org/netdev/aAEtSppgCFNd8vr4@LQ3V64L9R2/