Re: [PATCH net-next v4 9/9] selftests: ncdevmem: Implement devmem TCP TX
From: Stanislav Fomichev
Date: Thu Feb 20 2025 - 15:02:01 EST
On 02/20, Mina Almasry wrote:
> Add support for devmem TX in ncdevmem.
>
> This is a combination of the ncdevmem from the devmem TCP series RFCv1
> which included the TX path, and work by Stan to include the netlink API
> and refactored on top of his generic memory_provider support.
>
> Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxxx>
>
> ---
>
> v4:
> - Add TX test to devmem.py (Paolo).
>
> v3:
> - Update ncdevmem docs to run validation with RX-only and RX-with-TX.
> - Fix build warnings (Stan).
> - Make the validation expect new lines in the pattern so we can have the
> TX path behave like netcat (Stan).
> - Change ret to errno in error() calls (Stan).
> - Handle the case where client_ip is not provided (Stan).
> - Don't assume mid is <= 2000 (Stan).
>
> v2:
> - make errors a static variable so that we catch instances where there
> are less than 20 errors across different buffers.
> - Fix the issue where the seed is reset to 0 instead of its starting
> value 1.
> - Use 1000ULL instead of 1000 to guard against overflow (Willem).
> - Do not set POLLERR (Willem).
> - Update the test to use the new interface where iov_base is the
> dmabuf_offset.
> - Update the test to send 2 iov instead of 1, so we get some test
> coverage over sending multiple iovs at once.
> - Print the ifindex the test is using, useful for debugging issues where
> maybe the test may fail because the ifindex of the socket is different
> from the dmabuf binding.
>
> ---
> .../selftests/drivers/net/hw/devmem.py | 28 +-
> .../selftests/drivers/net/hw/ncdevmem.c | 300 +++++++++++++++++-
> 2 files changed, 312 insertions(+), 16 deletions(-)
>
> diff --git a/tools/testing/selftests/drivers/net/hw/devmem.py b/tools/testing/selftests/drivers/net/hw/devmem.py
> index 1223f0f5c10c..3d4f7fc5e63f 100755
> --- a/tools/testing/selftests/drivers/net/hw/devmem.py
> +++ b/tools/testing/selftests/drivers/net/hw/devmem.py
> @@ -1,6 +1,7 @@
> #!/usr/bin/env python3
> # SPDX-License-Identifier: GPL-2.0
>
> +from os import path
> from lib.py import ksft_run, ksft_exit
> from lib.py import ksft_eq, KsftSkipEx
> from lib.py import NetDrvEpEnv
> @@ -10,8 +11,7 @@ from lib.py import ksft_disruptive
>
> def require_devmem(cfg):
> if not hasattr(cfg, "_devmem_probed"):
> - port = rand_port()
> - probe_command = f"./ncdevmem -f {cfg.ifname}"
> + probe_command = f"{cfg.bin_local} -f {cfg.ifname}"
> cfg._devmem_supported = cmd(probe_command, fail=False, shell=True).ret == 0
> cfg._devmem_probed = True
>
> @@ -25,18 +25,36 @@ def check_rx(cfg) -> None:
> require_devmem(cfg)
>
> port = rand_port()
> - listen_cmd = f"./ncdevmem -l -f {cfg.ifname} -s {cfg.v6} -p {port}"
> + listen_cmd = f"{cfg.bin_local} -l -f {cfg.ifname} -s {cfg.v6} -p {port}"
>
> with bkg(listen_cmd) as socat:
> wait_port_listen(port)
> - cmd(f"echo -e \"hello\\nworld\"| socat -u - TCP6:[{cfg.v6}]:{port}", host=cfg.remote, shell=True)
> + cmd(f"echo -e \"hello\\nworld\"| socat -u - TCP6:{cfg.v6}:{port},bind={cfg.remote_v6}:{port}", host=cfg.remote, shell=True)
IPv6 address need to be wrapped into [], so has to be at least:
socat -u - TCP6:[{cfg.v6}]:{port},bind=[{cfg.remote_v6}]:{port}
But not sure why we care here about bind address here, let the kernel
figure out the routing.
Also, seems like "bkg(listen_cmd)" needs to be "bkg(listen_cmd,
exit_wait=True)", otherwise sometimes I see racy empty result.