Re: [PATCH net-next v9 5/6] selftests: net: Add busy_poll_test

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

Joe Damato wrote:
> Add an epoll busy poll test using netdevsim.
> 
> This test is comprised of:
>   - busy_poller (via busy_poller.c)
>   - busy_poll_test.sh which loads netdevsim, sets up network namespaces,
>     and runs busy_poller to receive data and socat to send data.
> 
> The selftest tests two different scenarios:
>   - busy poll (the pre-existing version in the kernel)
>   - busy poll with suspend enabled (what this series adds)
> 
> The data transmit is a 1MiB temporary file generated from /dev/urandom
> and the test is considered passing if the md5sum of the input file to
> socat matches the md5sum of the output file from busy_poller.
> 
> netdevsim was chosen instead of veth due to netdevsim's support for
> netdev-genl.
> 
> For now, this test uses the functionality that netdevsim provides. In the
> future, perhaps netdevsim can be extended to emulate device IRQs to more
> thoroughly test all pre-existing kernel options (like defer_hard_irqs)
> and suspend.
> 
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca>
> Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
> Acked-by: Stanislav Fomichev <sdf@fomichev.me>

Reviewed-by: Willem de Bruijn <willemb@google.com>

minor nit that ULONG_MAX can not be true with uint32_t on 64-bit
platforms. Definitely no need to respin just for that.